THE ALFALFA GENOME

Responses to the Questionnaire

D. K. Barnes

USDA and University of Minnesota (Retired)

Minocqua, WI

INTRODUCTION:

It has been enjoyable to consider both what was and what might have been. One thing certain was that we have worked on a great crop during an interesting time. It reminds me of the comment made to me by Mr. J. C. Stevens, USDA, Chillicothe, Texas (developer of male sterility in sorghum, USDA and Texas A and M), when he said that he had been stealing from the government for many years because they had been paying him to do what he would have done for nothing.

BENCH MARKS:

• Introduction of winterhardy germplasm into the northern U.S. and Canada.
• Development of bacterial wilt resistance by scientists at Wisconsin, Minnesota and Canada. This laid the basis for all later pest resistance research.
• Development of resistance to spotted alfalfa aphid, anthracnose, stem nematode and Phytophthora root rot. This produced resistance to primary pests in the West, Midwest, Mid Atlantic areas of the U.S. This research was all carried out by public scientific research teams that simultaneously developed the first resistant variety and also the basic research that described the pest, its life cycle and control. (Note: Later releases of new types of pest resistance primarily were developed by private industry. It was difficult for industry to simultaneously breed new multiple pest-resistant varieties and to do the basic research on the pest and its control. Conversely it was equally as difficult for the public researchers to develop basic pest resistance information and breed new varieties with all of traits necessary to insure acceptance by the seed industry and forage producers.
• Development of publications that described different alfalfa pests and their distributions within the U.S. This was important for the seed Industry and the marketing of varieties with new pest resistances. It was also important for producers because it allowed them to identify their own production problems and to determine if various types of pest were important in their area. (Note: The development and use of varieties with multiple pest resistances greatly reduced stand losses during seeding and during the early production years. During the 1970's and 1980's seed usage in the U.S. was reduced about 50% while maintaining approximately the same 25 million acres of alfalfa. The American farmer won while the seed industry appears to have lost from the advances made in developing multiple pest resistance for alfalfa.
• Nitrogen fixation research on alfalfa has provided the world scientific community with a great deal of basic and practical information. Alfalfa was the first plant species to be bred for increased nodule enzymes.
• Publication in 1988 of the alfalfa monograph (Alfalfa and Alfalfa Improvement) was a major accomplishment. It included a broad range of authors who represented the public and Industry research programs that produced most of the research accomplishments between 1945 and 1985. Only about 25% of the 80 authors are still active in alfalfa research and extension in 1998.
• The alfalfa research community has done an excellent job at collecting, increasing and evaluating world germplasm for traits of current interest. This should provide germplasm for many generations of alfalfa scientists.

WHAT MIGHT WE HAVE DONE DIFFERENTLY:

• Reduced the number of varieties released to the public.
• Paid more attention to the loss of winterhardiness during variety development in the 1980's and early 1990's.
• Generally alfalfa research progressed in a logical progression during the last century based on a spirit of cooperation and respect among the scientists. Essentially everyone contributed to the accomplishments.

WHAT DIRECTIONS SHOULD BE TAKEN IN THE NEXT CENTURY:

• I would emphasize research that could provide new uses for alfalfa, such as energy production and/or bio-remediation. If new uses are not found the acreage of alfalfa in the U.S. is very likely to significantly decline. Many new uses resulting from genetic engineering may increase alfalfa utilization without increasing acreage.
• Pest management practices must continue to include ecological considerations that do not encourage the pest to develop resistant biotypes. This would include developing resistant varieties with no more than 60 to 75% resistant plants.

OTHER THOUGHTS AND PHILOSOPHIES ABOUT ALFALFA IMPROVEMENT:

I am not certain if my ideas add any original information to your conference, but they are what I consider to be some of the high points for the area of applied breeding. It appears from some recent conversations that the alfalfa research industry is going the same direction at the Exxon and Mobile merger. This just illustrates how fleeting history can be. It took 25-30 years to develop the current industry research programs. The number of industry breeding programs may soon be reduced from a high of about 13 programs to two major programs plus two or three smaller programs. Likewise there appears to be a continuing reduction of public programs. Unless there is an alfalfa crises it may be difficult to change the current direction of history.

Pietro Rotili

Instituto Sperimentale Colture Foraggere - Lodi, Italy

Preliminary remarks

Our research activity is aimed at the creation of new populations. Therefore, opinion on this activity is referred to a) the final product (the new variety) and b) the adopted process. For the first point, the main aspects concerning forage production and quality; as to the second point, all those elements totally belonging to the subject called ‘breeding methodology’. The studies in this sector aim at linking the different phases of the new cultivar creation process. The breeding is not, as wrongly supposed, a variety maker but a scientist studying how to create a variety. Obviously, the verification of the validity of such a process must be the final product, i.e. the variety. Therefore, the breeder creates the variety prototype which will be a reference point for the new variety making activity. Breeding as the science of variety constitution is the result of integration of different subjects such as genetics, agronomy, biology, phytosociology, etc. The variety constitution process consists of three elements: the method, the procedure and the techniques. The method is the series of successive steps and acts needed in the construction process of a new variety (analysis of parental populations - phenotypic selection - genotypic selection - synthesis); the procedure is the way to perform the method, i.e. the rules of application. Finally, the techniques are the different ways of operating during the work.

BENCHMARKS IN ALFALFA BREEDING IN THIS CENTURY, AND THINGS WE MIGHT HAVE DONE DIFFERENTLY

1 - Today, we have a good understanding of autotetraploid genetics and its consequences in alfalfa breeding and variety syntheses. This was not true fifty years ago. In other words we have a good understanding of the mechanisms ruling heterosis and inbreeding effects. What has this new autotetraploid knowledge gained us? Certainly not much in the way of improving forage yield in itself (vigour). As alfalfa breeders have had only limited success in increasing vigour, they have turned much of their efforts to breeding for pest resistance, greater persistence, and wider adaptation. These pursuits have been highly successful.

2 - It is true that the genetic advantage in forage yield for alfalfa in this century is very low (about 10%). Why? There are the difficulties connected to the plant characteristics: autotetraploidy and allogamy. One must add other difficulties: the reproductive apparatus with hermaphrodite flowers, plant architecture (herbaceous plant) and the conditions in the meadow. All that is not enough to explain the very moderate success obtained by breeding. Other factors can play a role: for example, the research programme strategy and its effectiveness. In perennial species the groups studying the variety constitution process as a whole are very rare. On the contrary researches on the different phases of such a process are very numerous. Without a conceptual apparatus integrating the different phases in a unique programme, the great majority of these researches are very often repetitive and of no significance. Today there are on one side excellent studies on molecular biology, genetics, physiology, etc.; on the other side the variety constitution process is the same of fifty years ago. This situation of separation does not permit any progress and is very expensive.

3 - Many people make varieties; among them, breeders who improve the varietal process by means of new ideas and discoveries, are rare. In the breeding work, genetics, physiology, agronomy, molecular biology, phytosociology, etc. play a part; however, breeding is not the sum but the integration of these subjects. Can breeding be defined as a science or a technology? In recent years the borderline between these fields has become so slight that it is difficult to identify it. It is necessary to say that in the laboratories of science applied to agriculture the number of pathologists, biochemists, geneticists, cytologists and over all of molecular biologists is increasing. On the contrary, the figure of the breeder has nearly disappeared. In a complex forage species as alfalfa it will be impossible to achieve important advances without breeding science. Important concepts as genetic load, biological density, adaptive reaction, vigour, linkat, level of complementarity and others will be able to show the whole of their operational value only through breeding.

4 - Concerning the problems of method we have to observe that the importance of selfing in the variety constitution process has been understated.

For example, in the USA selfing is not utilized for variety constitution but to produce material for testing hypothesis concerning alfalfa genetics. Extensive research have been carried out for vigor ‘via’ maximum heterozygosity. These researches has provided important information in the field of evolutionary genetics but have not been useful for breeding. The vigour is produced not only by heterozygosity but also by other factors as shown in the following statement: Genome value = Quality of genes + Quality of linkats + Interaction within chromosomes + Interactions between chromosomes (heterozygosity). The most efficient way (in terms of time and means) to improve the quality of genes and linkats lies in the use of selfing. Besides, there is a lack of in depth studies on variety models.

5 - The problems of procedure have been completely overlooked.

For example, the estimation of vigour and of the genetic parameters are not independent from the procedures used. The efficacy of the mother plant choice or the progeny test is a function of the density. This proposition is particularly important when the construction of new varieties concerns an intensive forage system. Must the procedure of spaced plants then be completely discarded? In some conditions it can be efficient. In difficult pedoclimatic environments the forage yield and chiefly the persistence are based on stress resistance. Conversely, in fertile environments forage yield is due to the capability of the plant to transform the naturally and artificially available resources into biomass. Therefore, there are two different types of biological machinery. The procedure of spaced plants can give positive results when hardiness has a predominant role, but it is ineffective in non-stressing conditions, where the resistance factors play a secondary part in comparison with those directly involved in the expression of vigour. In fact, the factors of forage yield are not the same in spaced plants and dense sward. The efficacy of breeding for vigour is closely connected to the procedures. For us vigour is the productive biomass capability. Vigour estimation is expressed by the following formula:

Vigour = DMY t₁ - DMY t₀ /(t₁ - t₀)

DIRECTIONS FOR THE NEXT CENTURY

A new alfalfa variety must have higher vigour and quality of forage and persistency to be successful on the market. But it is not enough; an outstanding seed-yield potential is needed. In other words the new variety must be a well-balanced product from the biological point of view. For this reason there is a very little probability that molecular biology and other biotechnological technics may directly produce a population adapted to agricultural practices. From molecular biology we could get resistance sources to introduce in the variety constitution process. On the contrary the molecular marker seems to be the most promising sector; selection assisted by molecular markers (RFLP type) during the process of variety constitution may concern different fields:

a) the estimate of heterozygosity and genetic diversity levels, in parental clones and in parental single hybrids;

b) the prediction of values of a cross through information on parents;

c) the management of variability at the genetic resources level ‘sensu lato’: grouping of clones or single hybrids based on combining ability.

Once said that, future researches would resume the studies on breeding methodology. In particular:

1) to set up a plant model for vigour, quality (optimal leaves/stems ratio), for the resistence to a high number of cuts per year and for seed production;

2) to resume studies on selfing for breeding;

3) to set up a variety model allowing the production of F1 commercial seeds;

4) to find a technique (RFLP type) allowing to rapidly monitorize heterozygosity level and genetic diversity of a population.

SHORT COMMENTS ON DIRECTIONS FOR THE NEXT CENTURY

1 - In practice, an alfalfa single plant has no interest because the exploitation concerns the stand and not the plant. In the alfalfa stand system the plants represent the constitutive elements, the structure is the morphological expression of the relationships among them. The aim of breeding is to improve the alfalfa stand. A positive result is possible only if both the parts of the system are improved, i.e. the plants and the structure. Indeed, an optimal structure is necessary but not sufficient to secure a high forage yield. The same is true for the plants, a good genotype is indeed necessary but not sufficient. Selfing and selection at agronomical density is a very powerful tool in order to improve the genome and the stand structure.

2 - The vigour of a plant is the result of the quality of the genes and their interactions. If we accept Demarly’s hypothesis on the organisation of the alfalfa genome, the quality concerns the single genes as well as the gene clusters organised in linkats. To simplify, the objective of the different variety constitution process is to cumulate the vigour linked to the heterozygosity with that linked to the quality of genes and linkats. The main obstacle is the difficulty in splitting them apart. An approach started long time ago at Lodi consists of the reduction of heterozygosity effects through selfing and subsequent intercrossing of the most productive partly inbred clones. The use of restriction fragment length polymorphic markers (RFLP) seems to be very useful to monitorize the heterozygosity level of the plants in order to select the best performing ones having, at the same time, a reduced level of heterozygosity. In fact, the major advantages of selfing are the following:

a) It is possible to homogenize plant material for physiological characters. Great genetic variability for characters such as time and quantity of regrowth, growth rate and flowering is a factor against persistence and forage yield stability. Such variability produces different degrees of root reserve recovery at cutting time.

b) Selfing assisted by selection is the most effective way to concentrate the genetic structures (genes and linkats) favourable to vigour. Therefore, it is possible to improve the breeding value of the parents (their general combining ability).

c) Selfing is the most effective way to explore the genetic load.

d) It is possible to identify plants less sensitive to inbreeding.

3 - Today there is not yet an answer to the question about the possibility of selecting plants tolerant to inbreeding but we know that variability in response to selfing is high. We know as well that selection is not effective if the level of heterozygosity has not been reduced. Unmasking is necessary to assess and select the ‘direct’ value of genes and linkats. Is selection associated to selfing always effective? For several qualitative characters the answer is positive, for vigour it is negative. Selection for vigour within the selfed families is ineffective at spaced plants; therefore, to obtain a positive result the use of two factors should be combined: selfing and stand density. The second phase of the variety constitution process (hybridization phase) will permit restoration of the part of vigour linked to heterozygosity.

4 - Why is selection in an autotetraploid plant such as alfalfa so successful for a character as complex as yield? Demarly (1968) coined the word "linkat" to represent the chromosome segment that remains intact for more than one generation. This hypothesis, simplifying the general structure of the genome, allows to understand the rapidity of concentration of favorable genetic factors present in the mother plant. In this case the unit of segregation is not the gene but the linkat.

5 - Interpreting the coefficients of inbreeding at face value and considering inbreeding to be deleterious, the synthetic varieties would always be superior to the free hybrid (Busbice). However, this is not true. First, the computed coefficients of inbreeding assume random mating and equal survival of all offspring. We know that this does not occur. Inbreeding causes the death of many individuals. There is competition for survival among gametes, developing zygotes and plants. The result is that the computed coefficients of inbreeding are greater than the actual, and the larger the coefficient of inbreeding, the greater is the difference between computed and actual values. Rotili & Guy (1991) have chosen another way to compare synthetics at 4 and at 8 components to the corresponding free-hybrid varieties. The examined parameter is the number of alleles per locus and per plant. In the free-hybrids the calculation is based on the hypothesis of 100% of crossing between the parental populations. Such hypothesis is not realistic. But even in the case of 50% selfing, the total number of selfed seeds would drop below 10% because of the negative effect of inbreeding on seed setting and on pod fertility. This percentage is easily overcome by the competition effect at alfalfa stand level.

So, the value of the different methods of variety creation cannot be determined from theoretical considerations alone, but the methods should rather be evaluated experimentally.

R. P. Murphy

Cornell University - Ithaca, New York

BENCHMARKS OF THE CORNELL PROGRAM

1. Use of backcrossing and utilization of "Du Puits et al" germplasm and Narragansett germplasm. Both were unique and utilized in the face of criticism of our contemporaries. The USDA and northern states were adamant against the "French" germplasm (they equated the sorts we had identified as useful with Provence sorts - the only French seed in commerce). Prof. Graber suggested that not be included in the Narrgansett National Seed Project because it was susceptible to bacterial wilt. He failed because of our strong support and the fact it was superior to Vernal where wilt was not a factor. Of course the French germplasm gave rise to Saranac, Saranac AR, Honeoye and several of Viand’s varieties (individual releases to seed companies) and Narragansett gave rise to Iroquois, Oneida, Mohawk and several of Viand’s varieties (individual releases). The only merger of these two germplasms was Oneida VR [Oneida and Vertus - Du Puits origin)] by Viands and Lowe - this is still a good variety but is not marketed because it is not an exclusive variety.
2. I have no information except casual comments that these germplasms plus Vernal were the "backbone" of the initial private breeding programs for the northern and northeastern regions.
3. Demonstation that the variation in OP seed setting in autotetraploid alfalfa is not associated with aneuploidy as many had hypothesized. Also the character with greatest association with OP set is pollen production (Sayers and Murphy 1996 Crop Sci. 6:365-368) We have been successful in improving seed set with Iroquios, Mark II and subsequent varieties by selection for pollen production.
4. THINGS WE MIGHT HAVE DONE DIFFERENTLY
1. Greater emphasis on more uses: pasture, short rotations, nitrogen soil building, etc.
2. Greater introgression of "wild" germplasm in efforts to affect above ideas.
3. Too much emphasis on resistance to minor diseases and pests at the expense of other traits.
4. DIRECTIONS FOR THE NEXT CENTURY
1. Follow through on above ideas.
2. Determine value of marker-assisted selection and genomics. (Can we afford them?)
3. Continue search for characteristics for transgenics.

THOUGHTS AND PHILOSOPHY ON ALFALFA BREEDING

Old timers should never philosophize. But I think any reduction in heterozygosity is somewhat contrary to overall vegetative yield. It has been my experience that recurrent selection for anthracnose resistance (highly heritable character) has led to a slight reduction in total mass yield.

Honeoye AR (never released) less than Honeoye

Mohawk less than Iroquois

I should quickly point out I have not seen these yield reductions with breeding for BW, FW, PR. The potato leaf hopper resistant types often are less vigorous but I equate this to linkage etc. Oh yes, all ML types I have selected have some reduced total mass yield - linkage and reduced heterozygosity and pliotropic effects may be hypothesized.

Sincerely,

"Murph"

Dwayne A. Rohweder

26425 S. Ribbonwood Drive

Sun Lakes, AZ 85248

As I see it, the following are benchmarks in alfalfa breeding and management during this past century.

1. Growing the crop — Alfalfa introduced into the Georgia colony failed. But, it persisted up the west coast of South America into California. We had to learn how to grow alfalfa as we brought it across the mountains, the great Plains, and into the Midwest and East. This was a major step in Wisconsin; we still are trying to refine the components of that management program in order to have the alfalfa persist, obtain top yields, and still maintain the environment. The latest change is to lower fertility levels in order to preserve the environment; I wonder if the long term effects on crop production have been determined.

2. Winterhardiness — Through selection and breeding we have greatly improved the winterhardiness in alfalfa. We now need to know more of the cellular characteristics supporting winterhardiness to permit breeding for better persistence.

3. Multiple Pest Resistance — Along with winterhardiness, we have improved the disease resistance of alfalfa. In early days, if we lost a seeding, it was due to damping off disease etc. Today, we know of at least six seedling diseases that influence stand establishment, emergence and survival. Subsequent to establishment, if we lost a stand it was due to winter injury. Ranger and Vernal were the first varieties to have improved winterhardiness and Bacterial Wilt resistance. Today, there are at least seven diseases causing stand decline and that are included in variety characteristics.

Adding the first three factors together, we have provided for improved persistence in the crop.

4. Yield — In a gross way we increased yield when we introduced the Flemish lines from Europe. They did not persist, but with crossing with winterhardy varieties, persistence was improved and the larger stems of the Flemish lines increased yield. We now need to determine the genetic relationships that influence yield in order to make the next step. From all I read, yield is still a major factor considered by producers.

5. Carbohydrate Production and Use — Early management involved taking one cut and harvesting "Patriotic Hay" around the fourth of July because they thought that alfalfa would not persist with more frequent cutting. The determination of the carbohydrate production and use pattern for alfalfa as well as for several other legumes and grasses permitted designing cutting schedules to increase yields and improve quality. If you will remember, the dairy farmers in Wisconsin told us in Extension that we had to make changes so they could more profitably produce milk. Now distinct pathways of production and use as well as components of this fraction must be refined.

6. Quality — Dairy farmers again told us that we needed to go back to the drawing board if milk production was to be profitable. You will remember that we started with only five or seven varieties to determine if they did differ in quality. When we found how much difference there was, commercial plant breeders selected two paths to improve quality — the multifoliate route and the HQ or high quality route. Over the years top dairy farmers have told us that multifoliate alfalfas per se do not improve quality when the increased number of leaflets are on large stems. The HQ route, when genetic materials were available, significantly improved quality, but the first releases tended to be lower in yield. This has been corrected in later releases and now HQ genetics has been introduced in a broader range of winterhardiness.

The problem is to determine how to further improve yield and quality at the same time. I visited with a consultant today from Texas; dairy producers there will not accept any alfalfa having a Relative Feed value less than 165.

7. Improved Harvest Schedules — Combining the first six factors have permitted the development of improved cutting schedules to increase yield and improve forage quality. Dale’s three cutting schedule is used widely. The four cutting and higher that Mike Collins and I designed has pointed the way to further increases in quality and retain persistence with proper management. I find that this is a request from dairy producers around the world.

8. Insect Resistance — Management of insects in alfalfa and other forages has been obtained by-and-large through the use of insecticides. With the greater concern for the environment, producers are asking for a better method of insect management. Commercial plant breeders have resurrected a characteristic found a few decades back — glandular hairs - to manage potato leafhoppers. In moderate infestations the characteristic has some value, but in heavy infestations, using high yielding varieties having proper characteristics with proper pesticide usage gives greatest production. Additional work is needed.

9. Forage Drying — We know how to speed the drying process through use of mechanical means. However, can we genetically manipulate the plant to do the same?

10. Improved Water Use — Some work that I did with Champ Tanner at Hancock affirmed that alfalfa is a drougth tolerant plant and pointed out several steps to improve water use per unit of dry matter produced in alfalfa and why alfalfa is superior to cool season grasses.

11. New Fibre Fractions — The isolation of the new fibre fractions; how they influenced animal behavior, and the development of Near Infrared Reflectance NIRS as a rapid, accurate evaluation tool has permitted animal scientists to better utilize varying crop qualities in more efficient animal rations.

The new hay standards developed by Rohweder, Barnes, and Jorgenson utilizing this technology was the first major step since the development of the Proximate analysis technique in Germany in 1850. Prior to this step, alfalfa generally was evaluated on Crude Protein concentration and there was little or no difference among varieties. These tools have permitted livestock producers to design efficient Total Mixed Rations TMR utilizing feed stuffs available

to them locally. Those feedstuffs might be cottonseed, cotton hulls, corn silage, grass forage, corn silage, citrus pulp, roasted soybeans, etc.

12. Leaf Protein and other new ideas — The production of leaf protein from alfalfa has signified that alfalfa can produce food components for humans in protein deficient parts of the world. The product also can be used for livestock feed. Improving the carotene concentration has improved the product for poultry production.

Some work is still being done to reduce the chances of bloat.

Work is now being done on improving phytase in alfalfa to assist swine and poultry especially to improve utilization of phosphorus and not place so much into waste

We have found that the lignin in the upper part of the alfalfa plant is different from the lignin in the lower part of the plant. If something can be done to improve the lignin in the lower part of the plant it will improve Digestibility and Intake.

Breeders are working on increasing the fibre production in some alfalfa varieties for energy production.

Dale Smith

P.O. Box 1400

Sun City, AZ 85372-1400

Cultivars are needed that have different maturity dates, such as an early-flowering, medium, and late-flowering cultivar. A large grower using one maturity class will have all his acreage come to early flower and harvest at the same time. With two or three different maturity classes, he can harvest in sequence as they come to the right stage to harvest.

Maturity comes into play in a second manner when alfalfa is grown in mixture with grasses, such as orchardgrass, bromegrass, or timothy. Using a cultivar of the maturity-class of Vernal, cutting the first crop at first flower catches brome and timothy at a stage of growth that they are virtually wiped out in short order. However, the Vernal maturity-class fits well with orchardgrass, and orchard survives the spring, first-flower cutting. Brome and timothy have survived well in northern Wisconsin where the first flower of Vernal occurs late and the brome and timothy grow and develop rapidly with the cooler spring temperatures.

The Falcata strains of alfalfa seem to have some possibilities of germplasm for developing grazing types. This work seems to have more or less come to a halt in recent years. Have the Falcatas lost their appeal or has breeding for grazing lost its interest?

Root-type still seems to me to be an important aspect, but receives little attention. One would think that an alfalfa with much root branching in the soil surface area would have an advantage over the tap-root type. It has been shown that alfalfa absorbs most of its minerals from the surface few inches of soil. This is exactly where fertilizers are placed and minerals like K and P move very little in the soil. It has been a puzzle to me why the nonhardy cultivars of the arid southwest need to be tap-rooted. They are almost exclusively irrigated (and a tap root is not needed to get moisture at deep depths) and again minerals are surface applied. Remember also that minerals become more difficult to absorb from the soil at deep depths because of lower temperatures and lower oxygen levels.

A crown-type with many rhizomes would seem to have its value, and one of the several reasons for the persistence of Vernal. When winter-damaged, rodent-damaged, or disease damaged, the plant has much more of a chance to survive when there are an abundance of rhizomes. Their recovery would be even more enhanced if the rhizomes were able to produce roots, no matter how vigorously.

It is well-known that carbohydrates are synthesized in the leaves of alfalfa during the daylight hours and accumulated largely as starch, and are translocated as sugars to growing regions of the plant or to the root for storage during the nighttime hours. What is needed to make good silage from alfalfa herbage is high levels of nonstructural carbohydrates in the vegetation when ensiled. This would occur during later hours of the afternoon, but especially if the temperatures are cool. Starch can accumulate to high levels (as high as 40% starch by dry weight) in the leaflets during 2 or 3 days of cool weather as compared with 2 or 3 days of hot weather. Is it possible that enzymes involved in carbohydrate synthesis can be controlled (as they have been in sweetcorn) to slow down the conversion of starch to sugars or the translocation of sugars to the roots so that high levels of nonstructural carbohydrates are maintained in the leaflets to aid in ensilage? This may seem far-fetched, but little along this line has been attempted in the legumes.

Deborah A. Samac

USDA-ARS Research Plant Pathologist

St. Paul, MN 55108

Benchmarks in alfalfa breeding in this century

As a relative newcomer to the field of alfalfa science and pathology I am impressed by a number of the achievements made during the 20^th century. In particular, the durability and level of resistance to a number of alfalfa diseases, especially root rot and vascular diseases, is striking. This type of achievement is rarely found in other crop species. Also impressive is the centralized organization of alfalfa scientists with the North American Alfalfa Improvement Conference. The standardized assays for disease and insect resistance, the availability of check varieties, and the network of scientists who are willing to provide microbial cultures and expertise are highly valuable resources. The level of cooperation between scientists in industry, government labs, and university labs and the willingness of established scientists to assist the newer scientist is very encouraging. For my research, the development of germplasm with high levels of regeneration from tissue culture and the development of methods to regenerate alfalfa was exceedingly important.

What might we have done differently in this century?

The genetics of alfalfa, the lack of a centralized customer base, and generally low value of alfalfa hay has hampered the full utilization of molecular biological techniques and biotechnology in alfalfa. Although we have obtained high levels of resistance to a wide variety of diseases, we know virtually nothing about the genes and genetic mechanisms conditioning resistance. Alfalfa was one of the first forages and first legumes to be genetically transformed, yet the first transgenic alfalfa variety is still some years in the future. However, the economic and agronomic potential of transgenic alfalfa varieties is high. The perennial nature, high yield capacity, and adaptability of alfalfa make it an ideal crop for a number of new uses including: production of high value industrial raw materials, as a biofuel, and in phytoremediation of contaminated soil and ground water. Introducing genes for novel traits such as for heavy metal accumulation or herbicide detoxification would only enhance the value of alfalfa for these nontraditional uses. New uses for alfalfa and means to increase the value of alfalfa hay need to be pursued to ensure that alfalfa is retained in crop rotations with changing farming practices. As transgenic alfalfa varieties become available, we need to ensure that we retain the genetic heterogeneity for disease and pest resistance traditionally found in alfalfa varieties, or else face the inevitable selection of pathogens and insects able to overcome the resistance genes deployed.

What directions should we take in the next century?

There will be tremendous advances in the next 10 years in our understanding of the genome of alfalfa through genome projects conducted with its annual relative, Medicago truncatula, the barrel medic. Recently funded by a grant from NSF, the M. truncatula genome project is bringing together scientists from Texas A&M University, the University of Minnesota, The Noble Foundation, and the University of Georgia to investigate both structural and functional genomics. Initially, the goal in functional genomics is to isolate and identify a quarter to a half of the genes expressed in M. truncatula, particularly those genes involved in interactions with Sinorhizobium meliloti, several pathogens, and mycorrhizal fungi. These genes or sequences from the genes will eventually be arrayed on DNA "chips" that can be probed to determine the expression of all genes on the chip simultaneously. Probes will be derived from the total mRNA of specific cells, organs or whole plants, converted to labeled cDNAs. In a single experiment, we can examine the expression of thousands of genes in response to an environmental stimulus. Because the genes of M. truncatula and M. sativa are estimated to be >95% identical, we can utilize the DNA chips from M. truncatula to survey gene expression in alfalfa. The structural genomics goal is to map the M. truncatula genome, concentrating first on a linkage group dense with interesting potential resistance gene analogs and genes involved in the plant’s response to microbes. The M. truncatula map will serve as the hub to unite legume maps (ie; pea, bean, soybean, alfalfa) and the Arabidopsis genome map. With these tools, we will be poised to isolate resistance genes in alfalfa and understand their function, as well as genes involved in other important agronomic traits.

Jerry Nelson

Agronomy Department

Columbia, MO 65211

Benchmarks in breeding:

• Recognition of superior seed planted in west, and need for guidelines to reduce genetic drift during certified seed production.
• Involvement of private industry in scaling up the programs to make rapid progress.
• Capturing the rapid regrowth characters of low-dormancy types and incorporating them in higher dormancy types. This really helped industry establish itself.
• Leaf disease resistence to help production (retain leaves) and quality.
• Recognition of grazing tolerance as a character.
• Biocontrol (predators and cutting management) to help control the alfalfa weevil.

What to do differently:

• Improve persistence, especially winterhardiness and heaving resistence.
• Decrease potential for bloat.
• Improve adaptation, especially to low pH and poorly drained soils.

Directions to go:

• Reduce bloat potential.
• Enhance value as a fuel crop.
• Increase grazing tolerance (hoof traffic, dung spots), uneven grazing.
• Increase N₂ fixation.
• Develop bioherbicide properties (allelo chemicals) of alfalfa.
• Develop varieties that dry faster and are less damaged by weather.
• Improve seedling vigor, stand establishment is still a problem. May need engineers to improve implements, especially for low tillage into grass sods.

Other thoughts and philosophy:

• Need to get engineers to improve harvest, handling, and storage. Goal is to retain a quality product at low cost.
• Use of alfalfa in bioremediation. It is perennial, deep-rooted, and is "functioning" nearly all year.
• Improve water-use efficiency for dryland production in west, and with less irrigation where irrigation is acceptable.
• Will need to reevaluate the seed production requirements (restrictions) for genetically engineered cultivars. Being an outcrossing autotetraploid may cause problems in frequency of expression of traits in certified seed and in control of genetic drift between generations. Your ideas on inbreeding and maximizing heterozygosity may be relevant here.
• Genetic engineers and molecular biologists are going to need agronomists, physiologists, chemists, and anatomists to determine the desirability of traits and to verify their expression in the field. Public research has been doing this, but the pipeline of technology generation will not keep up with the use of technology by an aggressive private industry. New partnerships will need to develop.
• Alfalfa needs to be brought into the realm of the environment with fundamental studies on its role in soil erosion, water quality, manure applications, contributions to soil organic matter, relationships with air quality, and relationships with wildlife and soil biota. This may be the major avenue for funding on the public side.
• I was a bit critical above in point 2, mainly because the major players are private industry and are dependent on seed sales. The advent of grazing tolerance and the strong interest in grazing has led several companies to offer grazing types, even though the market is small. Developing heaving resistance and tolerance of low pH or poor soil drainage is currently thought to be low market, yet it has great potential. Public research will likely have to prove it is feasible before industry steps in.

Donald L. Smith

NuCrops, Inc.

Woodland, California

BENCHMARKS IN THIS CENTURY

1. The two most important benchmarks in alfalfa breeding in the 20^th century were (1) the identification and description of bacterial wilt resistance and (2) the development of cultivars using a breeding system first proposed for corn and later adapted to alfalfa which had been given the term synthetic variety (cultivar) breeding system. The foremost example of these two benchmarks is the variety "Ranger". This variety proved that pest resistance and increased forage production could be combined in a variety by using the synthetic variety breeding system.
2. A benchmark characteristic of the applied breeding program that I directed was the improved efficiencies that were put in practice in clonal selection and evaluation, experimental synthetic variety production, and field evaluation. The reason for concentrating on breeding and testing systems was the conviction that it was necessary that a larger amount of experimental materials be produced and evaluated thoroughly with a high level of precision in order to meet the objectives of this applied program.

   THINGS TO DO DIFFERENTLY

3. In the latter half of this century, much of the alfalfa breeding and evaluation was conducted under optimum or near optimum environmental conditions. In the process it is quite probable that considerable valuable variation for a wide range of stresses was left behind. Much of the on farm production included stress conditions and thus it can be argued that there were some additional yield gains that might have been realized, were not, due to the failure to breed and test under a wide range of stress conditions.
4. DIRECTIONS FOR THE NEXT CENTURY
5. Even though considerable research has been directed toward gaining more knowledge and understanding of the basic biology of alfalfa, much still needs to be known about the species before it will be possible to select and breed it with the expectations of developing "superior" adapted cultivars. In addition, heterosis has not been exploited to any great degree during this century and thus this area of research ought to be pursued vigorously. Research on classical plant breeding systems is also warranted if the effects of heterosis is to be fully realized. Classical plant breeding should not be forsaken in the quest for "value added" alfalfa cultivars.
6. Water use efficiency of alfalfa in the West has come under attack from various scientific and non-scientific origins. This is an area of research that should be receiving more attention relative to irrigated alfalfa production.

   PHILOSOPHY ON ALFALFA IMPROVEMENT

7. Research investments in biotechnology systems using alfalfa have become commonplace in recent years. Today, it is common knowledge that most of these systems are very costly and certainly in the private sector there are high expectations that such investments in these systems will bring substantial rewards to the investors. Any analysis of the consumer, namely the farmer, of these new alfalfas would clearly establish that this consumer is not particularly well off financially. Thus, the logical question that should be debated is "Is production agriculture in its present and foreseeable future financial condition in the United State going to be able to pay for products derived from such high cost research systems? As alfalfa scientists, we should take the time, sooner rather than later, to debate this issue of economics and alfalfa research activities as this new era is emerging.

Donald R. Viands

Department of Plant Breeding

Cornell University, Ithaca, NY

BENCHMARKS IN THIS CENTURY

• Flemish germplasm. The introduction of Flemish germplasm has enabled breeders to develop cultivars that can persist under more frequent harvest management systems. Although I don’t have data to prove it, I believe that mixing Flemish germplasm with more winterhardy germplasm in some situations has created some heterosis for forage yield.
• Multiple pest resistance. Much of the emphasis in breeding for several decades has been in protecting the crop from diseases and insects. Because alfalfa is a perennial, this emphasis has been necessary to keep the crop highly productive for three or more production years. Because alfalfa is an autotetraploid and most of the resistances to diseases and insects are multigenic, I think the development of cultivars with so many types of resistances is a great achievement attributed to the cumulative efforts of at least two generations of alfalfa scientists.
• Winterhardiness. Development of winterhardy alfalfa has expanded the use of this crop farther north.
• Forage Quality. Breeding research with alfalfa quality has been continuing for at least 25 years, and more intensively in the last decade. Significant achievements have been made in improving quality in our modern cultivars.
• Grazing tolerance. Improving tolerance to grazing conditions has improved the productivity of alfalfa under these conditions and has corresponded with the renewed interest in grazing forages.

WHAT MIGHT WE HAVE DONE DIFFERENTLY THIS CENTURY?

• Forage yield. Distractions by breeding for traits that have minimal or no significant economic impact have prevented breeders from focusing on perhaps the most important trait - forage yield.
• Winterhardiness. More emphasis in developing winterhardy cultivars could have resulted in more economic impact on the crop grown in northern climates. Some of the cultivars developed during this decade seemed to lack sufficient winterhardiness.

WHAT DIRECTIONS SHOULD WE TAKE IN THE NEXT CENTURY?

• Forage yield and winterhardiness. More emphasis is needed in determining or developing breeding methods for improving forage yield potential. For cultivars grown in the North, more winterhardiness is needed.
• Trangenics. Opportunities for introducing new traits from wild species into cultivated alfalfa will enhance progress in developing improved cultivars.
• New uses. Opportunities should continue to be explored for developing non-traditional uses (e.g., fuels, medicinal properties) for alfalfa.
• Quality. Forage quality is the most complex trait that alfalfa breeders have worked on in this century. Alterations in one quality component can affect a multitude of other traits in the plant. Because animal nutritionists are still determining what constitutes optimum quality, I believe there will continue to be opportunities to breed for improved quality by various approaches.

Other thoughts and philosophies on alfalfa improvement.

• The shift in breeding alfalfa from the public sector to nearly all private breeding has caused a paradox in my thinking. On the one hand, this shift probably has caused an increased rate of improvement in alfalfa. On the other hand, I am concerned that there are not many public breeders available to train graduate students in cultivar development.
• Another paradox is in patenting. Again, patenting probably causes more interest in private companies to fund research. On the other hand, it seems that it will lead to many cultivars with new traits, but inhibit the development of cultivars with the combination of all these new traits.

Lack of Alfalfa Yield Progress in the Midwest

D. W. Wiersma*, University of Wisconsin-Madison

Alfalfa development and improvement has been an ongoing work for most of this century. Both public and private researchers have worked to advance this crop through better performing varieties and improved management techniques. Because of the extensive efforts to improve alfalfa through breeding one would expect that genetic gain would be evident over time for this crop like it is for corn and soybeans. An extensive study conducted from 1982 to 1991 reports genetics gains of about 1% for alfalfa yield (Loiselle, 1992). In addition to genetic improvement, progress should be evident due to improved crop management practices. However, recent analysis of data from four Midwest states demonstrates that the yield of alfalfa in university tests has failed to increase over a seventeen-year period.

A larger database of alfalfa variety performance was developed at the University of Wisconsin containing forage yield data for trials conducted in Wisconsin (WI), Minnesota (MN), Iowa (IA), and Michigan (MI). The alfalfa database includes yield information from 1978 to 1996 (1966 to 1996 for Wisconsin) and contains approximately 25,000 data points. This database is designed to provide a public record of variety information for historic reference and to provide data for trend analysis.

Our initial study was an analysis of forage yield trends over time in the Midwest data set. Using linear regression analysis, we compared the yield of Vernal, trial means, and the top five performing varieties within each state by harvest year. On average, the yield of Vernal declined by an average of 0.75 tons per acre during the time period 1978 to 1996 for WI, MN and MI and by 2.0 tons per acre in IA. Trial means and top five performers either declined slightly or showed no significant change for yield over time. There is no evidence to conclude that alfalfa yields have increased in these trials during the last two decades.

A second study of this data set focused on comparing the ability to predict top ranking alfalfa varieties from one or more trials within a state. There is a 19.6% probability of a variety being ranked in the top 10% if it had been ranked in the top 10% of the same trial in the previous year. However, the probability of selecting a top ranking variety in a new trial drops to just 12.2% if it had been in the top 10% of other trials in previous years (2.2% greater chance than of selecting a top yielding variety than if selected at random). Based on data from this database there appears to be little ability to predict top performing varieties from previous trial performance.

While these data regarding yield performance trends is discouraging, it should be noted that alfalfa has benefitted from a dramatic increase in disease tolerance over this time period. The ability to tolerate various diseases has increased the adapted area for this crop, and in disease-prone environments this leads to greater yield potential. Likewise an emphasis on forage quality has led to an increased value for the harvested crop. But the challenge remains to increase yield of this crop.

Four major factors may account for the lack of alfalfa yield progress including crop management, alfalfa rotation effects, climatic changes, and genetics. Crop management may have changed during this time period to create a more difficult growing environment for the crop in recent years. However, in WI and MN trials, no correlation was found between cutting management and year of trial harvest. Likewise, examination of climatological data for these states revealed no evidence of a climatic shift that explain yield trends in these studies. One possible factor that could explain a lack of progress is an "alfalfa rotation effect". Frequent use of fields for alfalfa trials without rotation out of this crop could result in a buildup of disease pressure in these areas. Finally, a lack of yield progress could result from a widespread use of similar germplasm in the development of new alfalfa varieties. New studies are needed in the areas of crop management, alfalfa rotation effects, and breeding for genetic yield gain to help discover yield improvement barriers of alfalfa.

Reference

Loisell, F. 1992. Alfalfa breeding in the USA - present and future. Alfalfa Colloquium, March 12-13, 1992. Martin Luther University, Halle Wittenberg.

____________________

* Corresponding author, Daniel W. Wiersma, Marshfield Agricultural Research Station, 8396 Yellowstone Dr., Marshfield, WI 54449 (dwiersma@facstaff.wisc.edu).

Scott Hendrickson

Manitowoc County Extension

Manitowoc, WI 54221-1150

Regarding question 4, the farmer response would be that yield, winter hardiness, and longevity are critical to alfalfa improvement. This probably isn’t a new issue but there are some new factors in the mix. Corn silage, given high dry matter yields per acre, is the forage of choice on farms where cow numbers are increasing. Alfalfa has to yield more to compete. We still need to maintain a balance between these two forages. Winter hardiness remains critical. As cow numbers expand, feed inventories are stretched. Rarely, with the exception of 1998, do we have excess forage inventory to use in the event of severe winter kill. Stand longevity is important as well. Growers need and expect to recover the cost of increasing seed prices.

Fond du Lac County Extension

Fond du Lac, WI 54935

1. Century Benchmarks in alfalfa breeding
2. 1901 - First field trials with Grimm alfalfa in Minnesota

   1953 - Release of Vernal alfalfa - winter hardiness and BW resistance

   1963 - Release of Saranac alfalfa

   1972 - Release of Agate alfalfa with Phytophthora resistance

   1981 - Release of several varieties with Verticillium wilt resistance

   1990's - Release of varieties with aphanomyces root rot resistance

3. What might have been done differently in this century?
4. It’s always easy to look back and find mistakes. There seemed to be a period of time in the mid- to late 1980's when the major driving force behind alfalfa variety releases were company seed marketing divisions rather than research and development departments. Hence, "gee whiz"traits and the highest disease resistance index possible were given precedence over persistence/winter hardiness. Alfalfa growers suffered severe stand losses in the early 1990's. This, in part, resulted in competing forage sources permanently replacing some alfalfa acres.
5. What directions should be taken in the next century?
6. Breeders must continue to strive for increased yield potential to the extent possible in a perennial crop. Yield enhancements need to come from more than just a pest resistance trait. Rather, the increased production of dry matter must be a trait in and of itself. In Wisconsin, alfalfa acres are fast being lost to corn silage where producers are routinely harvesting 7 to 10 tons of dry matter per acre. As cow numbers expand faster than land base, yield becomes a critical factor in terms of both feed production and enterprise profitability.

   Continued efforts must also be made to enhance persistence, improve forage quality and/or delay maturity BASED ON MEASURED QUALITY PARAMETERS RATHER THAN MORPHOLOGICAL STAGE.

7. Other thoughts
8. Producers are tired of empty promises. Although the alfalfa marketing industry is not alone, it has had its fair share in the past 10 years --- persistence, improved quality with multi-leaflets, first generation potato leafhopper resistant varieties, etc. Alfalfa marketers are hurting both future sales and producer confidence by releasing varieties without adequate performance testing.

   A broader source of variety performance information that will supplement formal university testing trials needs to be made available to producers and crop advisors.

   "As long as the earth endures, seedtime and harvest..shall not cease." Genesis 8:22.

   Jeffrey J. Volenec

   Department of Agronomy

   Purdue University

   West Lafayette, IN 47907-11

1. Benchmarks this century

• Early use of Plant Introductions (Ladak, Turkistan, Cossack) in alfalfa improvement.
• Creation of certain paramount germplasms/cultivars like Vernal.
• Understanding the relationship between soil fertility, especially potassium and liming, and alfalfa growth and persistence.
• Cutting management research aimed at improving yield and persistence.
• Understanding the impact of heterosis on alfalfa performance.
• From my program I would highlight two discoveries that have had impact.

1. 1. the discovery of vegetative storage proteins in roots and our improved understanding of the role of root organic reserves in alfalfa regrowth after cutting.
   2. The discovery of certain genes that are highly expressed in roots and buds of winter hardy alfalfa plants that are not expressed in tissues of non-hardy plants.

1. Things we might have done differently

• • de-emphasize efforts to genetically improve forage quality. This species has very high quality to begin with. Small improvements we might acquire genetically can be easily lost during haymaking.
  • a better understanding of the relationship between pathogen resistance and persistence is needed. Markers and the extension education community implies that R and HR ratings for every disease are necessary for stand longevity and high yield at most locations. This "if some is good, more is better" mentality diverted resources from other efforts like selection for high yield and improved winter hardiness.
  • Create fewer cultivars, and make them genuinely different. Stop reselecting within "Vernal" types.
  • Make better use of genetic resources and plant introductions. The glandular hair trait is an example of how these resources can impact alfalfa improvement.
  • Initiate basic research on the biology of this species sooner. Alfalfa improvement in the future will be slowed by our lack of understanding of WHAT to change rather than HOW to change it.

• • Understanding the physiological, biological, and molecular bases for genetic difference in agronomic performance. Several traits to focus on initially include:
  • winter hardiness
  • Sitona (clover root curculio) - plant pathogen interactions
  • bloat
  • autotoxicity
  • fall dormancy
  • crown bud biology (bud dormancy; defoliation-induced breaker of bud dormancy)
  • forage protein quality
  • Develop a molecular map of the alfalfa genome in order to enhance selection efficiency when introgressing new traits
  • Use more P.I.s and exotic germplasms.
  • Bioinformatics focusing on alfalfa so we have a detailed database of what we know, and can actively pursue what we don’t.
  • Reduce our reliance on use of model systems (Arabidopsis, Medicago truncatula). Expand efforts on clearly relevant systems even though rate progress may be slowed. What we learn will be useful without wondering about species-specific responses.
  • Strengthen alliances among all members of the alfalfa research and development community.
  • Build a stronger, systematic way in which to fund alfalfa research. Public institutions are very reluctant to hire (or keep) scientists who cannot fund their research extramurally. The number of scientists in the public sector will continue to shrink unless significant resources for alfalfa improvement can be identified. Since no commodity group (ie., corn or soybean check off) exists for alfalfa research and market development, other approaches need to be creatively explored.

John Caddel

Department of Plant and Soil Sciences

Oklahoma State University

Stillwater, OK 74078

Major Benchmarks in Alfalfa Breeding:

1. The release of Buffalo and Ranger with bacterial wilt resistance.
2. The release of Vernal for its tenuous "tough" traits.
3. The release of spotted alfalfa resistant material for the central and southern plains then the incorporations of spotted alfalfa aphid resistance into "all" new cultivars to improve seed production in the west.
4. The release of CUF 101, a tough-to-beat nondormant with resistance to blue aphids.
5. The release of Alfagraze, the first variety selected for persistence with intensive grazing.
6. Minor Benchmarks in Alfalfa Breeding:
1. Identification of cold hardiness in Grimm and its use to improve cold resistance.
2. Identification of bacterial wilt and methods of selection to incorporate resistance into new cultivars.
3. Identification of aphid resistance (spotted alfalfa aphid and pea aphid) and methods of selection to incorporate the resistance into new cultivars.
4. Identification of phytophthora root rot and methods of selection to incorporate resistance into new cultivars.
5. Identification of other pest resistance (other fungal diseases, insect, and nematodes, as a group) and methods of screening/selection to incorporate resistance to them into new cultivars.
6. Perhaps a major benchmark or perhaps not worthy of mention is the recent development of resistance to potato leafhopper. Only time will tell if this will really contribute to alfalfa production or simply occupy time and be used as a marketing gimmick.
7. What Might We Have Done Differently This Century?
1. Paid more attention to selection for yield improvement under "ideal" as well as stress environmental conditions.
2. Paid more attention to selection for improved persistence under "ideal" as well as stress environmental conditions.
3. We should have never evolved into this situation of needing to release a hundred new cultivars each year. Releasing all these "new, but not-necessarily-improved" cultivars dilutes the efforts needed to breed for important new traits.
4. University variety testers should have continued testing varieties for the producers in their region rather than shifting to testing material for industry. We should not bend over backwards to help industry get "new, but not-necessarily-improved" varieties on the market each year with a minimum of testing. This change began in the mid 1980's and is now a major role for several University testing programs.
5. What Directions Should We Take in the Next Century?

   1. Breed for improved yield and persistence without much attention to individual traits that influence the improvement. The environmental and management conditions should be set and then selection for these two traits over a long period of time (at least 20 years).

2. Breed for improved yield stability without constraints of high quality. Most alfalfa is consumed by animals other than high producing dairy cows and stable yield is more important than the extremely high quality required by dairy cows.
3. Breed for improved alfalfa yield and persistence in mixtures with grasses -- both cool-season and warm-season grasses. Persistence, in this case, may come from improved ability to regenerate new productive plants from seed. Adequate quantities of seed can be produced in the central and eastern part of the US to perpetuate alfalfa stands, but the combination of autotoxicity, competition, and pest build-up inhibits the development of new plants.
4. Set up stringent criteria for the release of new varieties than include well-documented improvements for yield and/or persistence. Incorporation of herbicide resistance into mediocre alfalfa germplasm will happen, but it should not be released until real improvements in yield or persistence can be documented. We could learn a lot from the Canadians and Europeans that require "improvements" prior to release.
5. Reward breeding programs that avoid premature release of new traits in mediocre germplasm.
6. Other Thoughts and Philosophy:
1. Effectively alfalfa breeding is in the hands of about five programs (and decreasing by the month) that are competing for the same markets. Each program is run with extremely short term objectives - the release of as many "new, but probably-not-improved" varieties as possible. Only a minuscule effort (and research dollars) goes into long-term goals of improving yield and persistence. Too much energy is devoted to gimmicks that may improve market share by a fraction of a point.
2. Some of the other countries have "strange" criteria for releasing new varieties, and perhaps the US companies should pay attention to real improvements that are required by some countries.
3. Truth in advertising should be enforced in the alfalfa business. Every farm publication has claims of superiority that are not real.

Arcioni S., Damiani F., Mariani A., Pupilli F.

Istituto di Ricerche Sul Miglioramento Genetico Delle Piante

Foraggere del CNR. Perugia-Italy

Benchmarks in alfalfa breeding in this century:

2. The breeding for resistance to pest and disease has been enough successful and new varieties more tolerant than the previous ones have been produced.
3. The exploitation of most biotechnological acquirements (plant regeneration, genetic transformation, somatic hybridization, in vitro selection etc) have been applied to alfalfa and now this species is no longer considered recalcitrant but a model one.
4. In this century we might have done:
1. The exploitation of new approaches and methodologies for selecting and studying the cluster of genes affecting yield and their real impact on this trait in addition to heterozygosity.
2. Efforts could be carried out to verify the possibility to utilize alfalfa for reducing the level of environmental pollution by absorbing and/or metabolizing some of the chemical released by industries, cars etc.
3. Plant breeding has been very successful in autogamous species and in allogamous ones for which it has been possible to produce inbred lines and to exploit hybrid vigour (maize). In such cases the varieties are based on single or few genotypes. In alfalfa the possibility to create a similar situation (hybrid seeds and self-fertile genotypes) has not been deeply investigated.
4. In the field of biotechnology little emphasis has been put in the understanding the mechanisms at physiological and genetic level responsible for embryogenic ability and few efforts have been made for producing embryogenetic populations through cross hybridization.
5. Some of the directions that could be taken in alfalfa breeding are the following:
1. At least in the first decade of the next century some biotechnological efforts are necessary to reach some important goals in alfalfa breeding. One of the most interesting traits to be introduced into alfalfa is apomixis that can bypass gene and genotype interactions and makes of practical utilization the approaches of gene transfer such as genetic transformation, somatic hybridization, embryo rescue etc.
2. The utilization of molecular markers can no longer be delayed and they can give advantages in the assisted selection to identify the most useful parents and to evaluate the level of heterozygosity, specially when inbreeding is used to split apart the effect of heterozygosity from gene cluster on plant vigour. Moreover molecular markers can give and help to understand the molecular bases of yield starting with QTL analysis.
3. Set up of more appropriate conditions for genetic transformation in order to increase the yield of transgenic plants. Moreover since bacterial transformation and protoplast electrofusion involve regeneration from callus, two alternatives are possible: 1) to select for regeneration capacity during the process of variety constitution, 2) to use systems for genetic transformation which are genotype independent and do not require regeneration from callus.
4. Efforts could be made by using gene transfer for improving forage quality (amino-acids composition), tannin synthesis etc.) and for using alfalfa for the production of compounds utilized by industries and for reducing environmental pollution (bioremediation).
5. Breeding approaches should be focused to the development of varieties adapted to the dramatic environmental changes that will likely occur in the near future. These include i) drought and heavy metal resistant cultivars and ii) cultivars adapted to poor pollination conditions.

General Comment:

The research on apomixisis can imply a revolution on plant breeding and the role of private seed companies could decrease in favour of public research institutions and producer associations. Besides its universally recognized importance as one of the most valuable feed crops grown for livestock through the world, alfalfa seems to have potential not only for the production of many industrial compounds such as enzymes, cellulose, etc., but also for reducing environmental pollution by absorbing or metabolizing a lot of chemicals.

Bill Melton

Las Cruces, New Mexico

1. BENCHMARKS IN ALFALFA BREEDING IN THE 1900'S

1. Cultivar Development

1. Must start with introduction in the 1850's of the Spanish, Chilean, Peruvian types into the western U.S. and in the 1880's of the introduction of winder hardy types into the upper Midwest and Canada.
2. 1900-1925: Identification and selection of winter hardy types

Grimm - Around 1900

Ladak - 1910

Cossack - 1910

1925-Identification of bacterial wilt as a major production problem.

Ranger - 1941

Buffalo - 1942-1943

Vernal - 1953

1954-Discovery of spotted alfalfa aphid in New Mexico.

1955-Du Puit introduced and merchandised by a private company - first Flemmish.

-Kanza with high levels of resistance to both the pea aphid and the spotted alfalfa aphid.

-Discovery of biotypes of spotted alfalfa aphid.

1972-Release of Agate (MN) with resistance to Phytophthora root rot.

1973-Release of Arc (USDA) with resistance to Anthracnose.

1976-Release of CUF 101 for resistance to the blue alfalfa aphid.

1986-Nitro (MN) released for N₂ fixation.

Must also include as benchmarks the first multi-foliate varieties and the first glandular hair varieties.

1940's-Studies on efficiency in pollination.

1943-Importance of Lygus bugs as principle insect problem in seed production.

The largest and most important benchmark of this era was the development of the private seed companies due to (1) the development of the seed industry (2) the need for research to further variety improvement.

1. What might we have done differently?

2. The public agencies have decreased their efforts in actual plant breeding programs to the minimum! Assuming that this work would be carried on by the private companies. No one realized, or accepts the blame for the fact that plant breeders must be educated in all facets of research. They must be geneticists, stat and computer technicians, pathologists, entomologists, nematologists, chemists, physiologists, field people and alfalfa psychologists. In other words - you cannot teach a plant breeder in a lab or from a textbook. You must have a comprehensive program that goes from genetics and breeding mechanisms, to techniques, to testing and seed increase. This is not now available! Where is the next generation of alfalfa breeders going to come from?

1. What directions should we take in the next century?

1. We must back up a little bit and re-create our public programs as a training ground for plant breeders and to serve as an avenue to utilize and test the results of our biotech programs. The administration of our universities must take the bull by the horns and merge these units into one for either to be most effective, practically or from a training standpoint.
2. We, as plant breeders, have limited future progress. However, there is a way to correct our mistakes and surpass our past levels of performance. By using present DNA technology, we can unravel the equilibrium situation we have created. We can (1) separate modern, multi-pest resistant germplasms into distinct diversity groups (without losing the multiple pest resistance); (2) breed within diversity groups to improve specific traits and general combining ability; (3) determine combining ability between diversity groups and (4) determine the best way of varietal synthesis and seed production - THIS CAN BE DONE!
3. My guess is we must continue work in multiple pest resistance, and document evaluations and definitions. However, I think the direction of research will be to further reduce economic inputs into agriculture. We must increase fertilizer and water use efficiency and make our plants more resistant to environmental factors. If we can maintain or increase yield levels ever so slightly, with less input of money (fertilizer, water, pesticides, etc.) we will have a positive effect.

1. Packaging and quality of our product will be a big factor in future alfalfa improvement.
2. Gary R. Bauchan

   USDA-ARS, PSI

   Soybean & Alfalfa Research Lab.

   Bldg. 006, Room 14, BARC-West

   Beltsville, MD 20705-2350

1. What do you consider benchmarks in alfalfa in this century? (Benchmarks in general, in your program or both)?
2. General: 1) Utilization of recurrent phenotype selection especially for increased resistance to diseases and insects, 2) Manipulation of ploidy levels to produce cultivated alfalfa at the diploid level, and 3) Regeneration of alfalfa from tissue culture for use in transformation.

   My Program: 1) Identification of the mechanisms for self-incompatibility, 2) identification of individual alfalfa chromosomes using chromosome banding techniques.

3. What might we have done differently this century? Focused more on cytogenetics especially the mapping of morphological traits on chromosomes and the mechanism for chromosome pairing during meiosis. We have paid very little attention to the alfalfa genome cytogenetically especially compared to other crop species such as wheat, barley, corn, tomato, etc. Other crops have made tremendous strides forward based on cytogenetic research, why hasn’t alfalfa. Sure alfalfa cytogenetics is difficult but present trends demonstrate that it is achievable compared to other crops.
4. What directions should we take in the next century? 1) We need to focus on the mapping of the alfalfa genome. Not only the molecular mapping of alfalfa but the study of the whole genome including chromosomes (including chromosome morphology, heterochromatin location, chromosome abnormalities, etc.), gene interactions at the diploid and tetraploid level, genome relationships among and between the species in the M. sativa complex (9 germplasm sources) but also related species including the annual medics. 2) Another significant and important area of cytogenetic research is the study of chromosome pairing in an autotetraploid. There must be a genetic system like the 5BL gene system in wheat which causes the chromosomes in alfalfa to pair normally other than the development of multivalents. If the gene(s) for chromosome pairing in alfalfa can be discovered and manipulated then the possibilities for the incorporation of genes from related species for the improvement of alfalfa can be accomplished.
5. Other thoughts: I still believe that we have overlooked the potential of manipulating hybrid vigor using male-female sterility and/or self-incompatibility mechanisms.
6. Melvin D. Runmbach

   RR 3 Box 125

   Humboldt, Nebraska 68376

1. Benchmarks in alfalfa breeding in this century:

1. Application of the concept of "synthetic variety" breeding to alfalfa, culminating in the release of ‘Ranger’, ‘Atlantic’, and ‘Narragansett".
2. Realization by the seed industry that the breeding of alfalfa could become a viable economic enterprise and the employment of Dr. David Beard by Waterman-Loomis.
3. Acquisition and preservation of a large and highly diversified genetic base of Medicago species by the USDA Plant Introduction system and collectors such as N.E. Hansen and his successors.
4. Recognition of the economic impact of diseases and insects on alfalfa production and quality and the development of cultivars with multiple pest resistance.
5. Conception and breeding of an alfalfa cultivar specifically for grazing by Dr. David Heinrichs.

1. What might we have done differently this century?

1. We did not direct sufficient research resources to the development of methods to capitalize on heterosis and the breeding of hybrid alfalfa cultivars.
2. We did not develop efficient methodology for the incorporation of the Medicago species germplasm collection into alfalfa breeding programs.
3. We failed to develop a truly "bloat safe" alfalfa cultivar for grazing.

1. What directions should we take in the next century?

1. Correct the above-cited problems.

Thoughts About Medicago falcata

Dale Smith

P.O. Box 1400

Sun City, AZ 85372-1400

March 30, 1999

The notes and reprint about N.E. Hansen in the SDSU Farm & Home Research (Jan. 1999) stirred up lots of thoughts regarding alfalfa. I was privy to listening to L.F. Graber tell about N.E. Hansen and how he brought alfalfas back from his exploratory trips to Asia. As a horticulturist, I do not think Hansen was ever a part of the alfalfa discussions and alfalfa conference meetings that included people like Graber, Brink, Jones, Grandfield, Kieselbach, Willard, and others, but they all knew of his work with falcatas and Cossack.

I usually told my forage class something about the exploits of Hansen, especially at the point that I discussed Cossack that came out of SDSU in 1907. Cossack eventually became an important variety in Wisconsin when Grimm and the Commons failed to last because of the bacterial wilt disease. A 50-50 mixture of Cossack and Ladak became the recommended alfalfa to plant before Ranger became available with its wilt resistance. Both Cossack and Ladak had a weak resistance to wilt and they lasted a year or 2 longer than Grimm or Common. The mixture also lasted longer than when either Ladak or Cossack was sown separately. I do not know why that was, but it was a fact. And then, Cossack became one of the main parents of the variety Vernal developed by Brink.

One of the stories that is not mentioned in the N.E. Hansen article is the connection between Wayne Adams and Hansen. Wayne Adams got his Ph.D. in plant breeding with D.C. Smith at Wisconsin in 1947. Wayne then went to South Dakota State University. N.E. Hanson was still living (he died in 1950) and Wayne Adams struck up an acquaintance and had several conversations with him. Wayne found that one of Hansen’s nurseries, largely Turkistans and falcatas, still existed in what then was a golf course where they had been cut short and frequently for some time. Adams found the nursery and made selections from it. Some of these became material that went into Teton that was released in 1958. Adams left SDSU in 1958 to go to Michigan State University as the bean breeder.

The falcatas have always intrigued me, as they have to many people. They have deep set crowns that get protection from the soil against temperature, have very branching root systems good to prevent heaving and help to search for soil nutrients, and that they should have some importance in grazing. I was even more intrigued when working with root pieces in the greenhouse in CHO studies, I found root pieces of falcatas and Ladak producing adventitious buds on the pieces. Looking in the literature, I found that Oakley and Garver had observed this in 1913, and later Garver described plowing up a field and finding shoots arising from the roots below the level of where they had been severed. This seemed an interesting phenomenon to me (see Agron. J. 42: 398, 1950).

I was amused at the comments in the N.E. Hansen story where they found they were helping the pheasants in their nesting habits by the fact that the falcatas could be delayed in cutting until after pheasant nesting. I suppose this made the wildlife people very happy in South Dakota, but when we moved from 2 to 3 harvests annually in Wisconsin in the early 1950s, the wildlife people were very unhappy, and were on my back immediately. The 3 cuts put the first cut (near June 1^st) right when the hens were laying their eggs and nesting in early June. I do not know whether I was responsible for a decreasing population of pheasants in southern WI or not, but the wildlife people said I was. We had several conferences, but 3 harvests improved the forage so much that it was a done deal with the farmers.

Wayne Adams

Michigan State University-retired

5607 Colby Road

Crystal, MI 48818

I met Professor Hansen soon after taking up my position as alfalfa breeder at S.D.S.C. in 1947. Though retired at that time, he came to his office nearly every day, and sitting amidst his large untidy office surrounded by the accumulation of years - magazines, letters, books, pamphlets, etc. - he spoke to me not only of his alfalfa work, but of his introduction of bromegrass, crested wheatgrass, and the many fruits and vegetables he had brought back from his journeys in eastern Europe, Russia and Siberia.

The most memorable thing he said was that he had formed the habit early in life of arriving at his office in early morning to compose a few lines of poetry, which he claimed opened up the creative channels in his mind, stimulated his thinking process for the day ahead. I took him at this word, but he did not offer to show me examples of his poetry.

He had served as secretary of the S.D. State Horticultural Society for many years, and in that capacity had formed the practice of sending out to each society member renewal of membership or each new member, a teaspoon of seed of his Semipalatinsk alfalfa. Some of this seed ended up in the hands of homesteaders in Western South Dakota. (In the early teens of this century, by virtue of land speculators and popular advertising, nearly every quarter section of land was homesteaded, to a great extent by mid-western folk who believed the claims of the speculators that northwest South Dakota claims could become another Illinois or Iowa as a farmers paradise).

Hansen was convinced that the yellow-flowered alfalfa, particularly his Semipalatinsk strain, originating in the low rainfall region of what is now far eastern Kazakhstan, at about the same latitude as northern South Dakota, would find a home in the native grasslands of the Dakotas.

I was encouraged by his beliefs and optimism about the potential of the Russian and Turkestan alfalfa germplasm for introduction into the native pastures of South Dakota that I adopted his viewpoint and made it the basis of my program at S.D.S.U.

He turned over to me some of his notebooks and other records that provided names and addresses of homesteaders to whom he had sent seed. I then made exploratory trips in 1948 and ‘49 to northwestern S.D. and was, in fact, able to locate several sites where the yellow-flowered alfalfa still persisted in and around homesteads long since abandoned by those who had once settled there thinking to farm the land as though it were Illinois prairie.

In a roadside ditch near Lemmon, S.D., I found a single spreading yellow-flowered plant covering an area of some 18 feet in diameter. This was the first true root proliferous type I had ever seen. Sam Garver had described this characteristic in a publication as early as 1912 or ‘13. I introduced this clone into my breeding populations as a source of the root - proliferating trait, and out of the resulting populations, aided by subsequently acquired clones, came the root-proliferous range type variety Travois.

Hansen produced a M. sativa x M. falcata hybrid population by interplanting alternate rows of his Turkistan blue-flowered strain with his yellow-flowered Semipalatinsk. This population was produced, if memory serves me correctly, in 1914, and was planted on land near the S.D.S.C. campus which subsequently became a portion of the College golf course. Under close mowing and the encroachment of grasses, the original plants or their descendants persisted for the next 35 or so years.

I more or less stumbled on this site in 1948 and discovered numerous wide-crowned plants of a rhizomatous nature and ultimately extracted from the area the clones that became the parents of Teton alfalfa, developed as a pasture type.

To Professor Hansen must go the credit for not only recognizing the agronomic potential of the Turkistan and Semipalatinsk alfalfas, but having the vision of placing them in the South Dakota grasslands for grazing purposes.

One final item of some small interest, at least to me: Someone had placed in the S.D.S.C. Agronomy herbarium, a couple of plants of alfalfa of the Don strain, introduced by Hansen from the area of the Don River of European Russia. Don was a M. falcata type with very fine stems and small sickle-shaped pods.

Noticing that one of the pods still contained bright yellow seeds, I removed three such seeds, scarified them, germinated them and got two seedling plants. From root tips I determined that they were diploid. Thus, although unknown to Hansen at the time of his collecting this strain, he was responsible for introducing probably the first diploid stocks to the genetic resources of M. falcata in the U.S.

Personally, I still believe Hansen’s vision of the potential of the Russian and Siberian alfalfas for the grasslands of the U.S. northern great plains was an inspired one, and I am pleased that you and your alfalfa breeder colleagues have thought it appropriate to memorialize him with the paper(s) being prepared in his name.

Sincerely yours,

M. Wayne Adams

Milo B. Tesar

Professor Emeritus

Department of Crop and Soil Sciences

Michigan State University

East Lansing, Michigan 48823

1. BENCHMARKS IN ALFALFA BREEDING THIS CENTURY

1935 - F.R. Jones described bacterial wilt.

1942 - Ranger was released by Tysdal and Peltier in Nebraska as the first bacterial wilt-resistant alfalfa.

1949 - National Foundation Seed Project was established to provide adequate certified seed of public cultivars (mostly in California with high seed yields) with no more than one generation of increase grown outside the region of adaptation. This, together with wilt-resistance Ranger and Vernal in 1953 and other cultivars provided for adequate seed of alfalfas for consuming areas. US acreage increased from 19 to 28 million acres in the 1950-60 decade.

1953 - Vernal was released by Wisconsin as a hardy, wilt-resistant cultivar with satisfactory forage quality. It was the leading cultivar for 25 years and today is still a satisfactory widely used hardy cultivar of 3-cut non-intensive management.

1962 - The National Alfalfa Variety Review Board (NAVRB) standardized the description and review of new approved cultivars.

1963 - Saranac released by Murphy and Lowe in New York was the first moderately hardy, bacterial wilt-resistant Flemish cultivar.

1972 - Agate was released by Barnes and Frosheiser in Minnesota as the first cultivar resistant to Phytophthora root rot (PRR).

1974-1986 - Sorenson and others in Kansas laid the foundation for germ plasm resistant to the potato leafhopper.

1974 - Arc, the first alfalfa resistant to Anthracnose, was released in 1974 by MD, NC, PA and VA.

1976 - Norris developed near-infrared reflectance spectroscopy (NIRS) for determining forage quality.

1976 - CUF-101, resistant to the blue alfalfa aphid, was released by California.

1976-80 - Verticillium wilt was identified in Washington in 1976 and in Wisconsin and adjacent states in 1980.

Late 1980s - Grau in Wisconsin described the importance of Aphanomyces in stand establishment on wet soils.

The following two variety yield trials in Michigan utilized the most intensive management inputs available based on Michigan State University management research starting in 1955.

1970-1979 - Five cultivars (520, WL305, Iroquois, Weevlchek, and Atra 55) yielded an average of 7.59 tons 12% moisture/acre in the 10-year 1970-79 Central Alfalfa Improvement Conference (CAIC) variety trial in Michigan. The soil, pH 7.0, was a tiled, well drained Brookston loam, very wet in spring before tiles operated well. It was fertilized before seeding with 100 lbs. P and 200 lbs. K/acre and seeded at 12 lbs. Inoculated scarified seed per acre in mid August 1969. Starting in 1970 four cuttings (average dates of June 1, July 10, August 25 and October 20) were made to maximize yield and longevity based on earlier MSU research, Table 1. Based on these data, recommendations in Michigan for maximum yield include cultivars with resistance (R) to five of the most important diseases (BW, PRR, Anth, Fus, and Vert). Other recommendations are similar to treatments in 1970 except that 16 lbs. seed/acre, 100 lbs P₂O₅ and 400 lbs/acre of K₂O topdressing were used.

1982-1983 - in Michigan, Big 10 developed specifically by Don Smith of Cal West for maximum yields under intensive management, yielded 10.0 tons 12% moisture/acre annually without irrigation and 32 inches annual precipitation for the 2-year period 1981-1982. The same 4-cut system of June 1 to mid October was used as in the 1970-1979 10-year variety trial. Annual topdressing on the tiled, well-drained Brookston loam pH 6.9 was increased to 590 lbs. K₂O/acre to replace the 60 lbs. K₂O used for each ton alfalfa produced.

Narragansett and Webfoot were two cultivars developed based on characteristics other than the usual disease or insect resistance or high yield or persistence or quality.

1953 - Narragansett was developed in Rhode Island primarily from the hardy diploid DON. Even with little wilt resistance, it performed well in New York and Michigan, possibly attributable to one selection which survived the salt and water of the September 25, 1938 hurricane which killed other selections in the nursery. After crossing that selection with the cultivar DON, it was released as Narragansett. It became one of the parents of hardy wilt-resistant Iroquois developed by Murphy in New York. Iroquois had the third highest 10-year yield in the 1970-1979 36-variety in Michigan.

1987 - Webfoot was developed in Michigan from 20 Iroquois plants selected for their branching root habit and vigor from approximately 400 surviving plants in a 10-year old replicated yield trial on tiled, well-drained, fine-textured soil often very wet in spring. The progeny were subjected to recurrent phenotypic selection for resistance to Phytophthora root rot. Webfoot yielded well in North Central states and Ontario. Its branching roots and hardiness may explain its good yield and persistence on imperfectly drained soils and its good heaving resistance in Canada. In Minnesota on well drained soil in a 1987-1990 4-year variety trial with a December temperature of -30^oF with no snow in the third winter, Webfoot yielded 13% more than Vernal or the next best variety in year 4 and 11% more than Vernal or the next best variety in the 4-year trial. Webfoot has been used by a large seed firm as a parent in at least three of its hardy released cultivars on imperfectly drained soil, possibly because of its branching roots.

The high DRI of 25 for five diseases was possibly over emphasized at the expense of high yield and good persistence noted in the early ‘90s in some years with harsh winters in some northern North Central states. "Recent Forage Variety Updates" from the University of Wisconsin indicate a resistance level of R is adequate for alfalfa in that state as it is in Michigan.

Exploratory teams to be sent for higher yielding germ plasm than available.

Develop cultivars resistant to potato leafhopper.

Develop higher yielding, disease-and insect-resistant cultivars with good winterhardiness and quality for intensive 4-cut management with recommended or even higher rates of P and, especially, K fertilizer as shown in the Michigan 1970-79 10-year trials yielding over 7.5 tons 12% moisture/acre and the 10.0-ton 12% moisture/acre 1981-82 2-year average in Michigan.

Develop cultivars for specialty purposes, e.g., 5-cuts for dehydration with irrigation for the central states of KS, NB and OK and winter hardy grazing cultivars with disease and insect resistance and good quality.

Three and four cuttings and winter injury

The effect of cutting Saranac alfalfa three times (check) - June 1, July 15 and Sept. 1 or four times - cut 4 on Sept. 15, Oct. 1, or Oct. 15 with cut 1 on June 1, cut 2 on July 8 and cut 3 on Aug. 10 was determined at East Lansing in southern Michigan in 1968 and 1969. The residual effect of the four treatments was determined with two cuts in 1970 shown in Table 1.

Table 1

The data show that four cuttings (June 1-Oct. 15) yielded an average of 13% more in 1968-1969 (6.91 vs. 6.12 tons) than three cuttings for the 2-year of 1968-1969 cuttings.

The residual effect of two cuts in 1970 after two years of 3- or 4-cut treatments was similar (4.94 after the 4-cut treatment ending October 15 vs. 5.06 after 3-cuts ending Sept. 1). But if cut 4 was on Sept. 15, the 4.48-ton yield was 11% lower than the 5.06 tons of the 3-cut system.

These 1968-1970 data provided the information to take 4 cuttings (average June 1, July 10, August 25 and October 20) in the 1970-1979 10-year 36-variety CAIC trial in southern Michigan where the top five varieties yielded an average of 7.59 tons 12% moisture per acre. This same 4-cut system has been used in all 4-cut CAIC variety trials and in all extension recommendations for the southern half of Michigan since 1980.

This author is reluctant to suggest that the 4-cut system of June 1 to mid October now recommended in Michigan would be satisfactory for northern states such as Wisconsin. Our winters in southern Michigan (where the 4-cut system is recommended) are milder than in Wisconsin. Our lowest temperature in our area at East Lansing in the last 50 years has been about -15^oF compared to about -25^oF or below in alfalfa growing areas in Minnesota, North Dakota and Wisconsin.

How well our 4-cut system with cut 4 in mid October in Michigan would work in Wisconsin and North Dakota can only be determined by experimentation over a period of several years. Meyer in North Dakota has been experimenting with 3 cuts and the 4-cut system with cut 4 in late October with considerable success since 1994 as reported in his CAIC annual variety trials.

Please note: Additional Responses to the questionnaire are being summarized and will appear

here in the near future.

Selfing in Alfalfa Seed Production

D. E. Brown

Selfing in alfalfa during seed production has implications on both commercial and experimental populations. Without emasculation, cross pollination results in an unknown mixture of self and cross seeds unless the seed parent is male sterile or self-sterile thereby controlling pollination. Self and crossed seed have been reported within the same pod (1, 10). Some cross-pollination studies (5, 9) have used white, cream or yellow flower color as markers. All clones or lines had had varying degrees of self-fertility, and thus may have influenced seed composition. Bee species fixation, pollen or nectar attractiveness, self-fertility and flower color preferences may have flawed the random pollination assumption. Recent studies using normal flower colors (2, 8) found approximately 25% selfing under more normal seed production conditions. Selfing and resulting selfed seed in cultivars and experimental populations can have a big effect on research results. Variable estimates of inbreeding depression (3) may be due to the fact that most starting materials were not all S_o plants. Certain studies indicate that selective establishment pressure on mixed plant populations minimizes the survival of S₁ plants in competition with hybrid progeny (6, 11) and leads to stable performance of cultivars (4, 7).

1. Bradner, N. R., and R. V. Frakes. 1964. Crossed and selfed seeds within alfalfa pods produced by endemic pollinators. Crop Sci. 4:111.
2. 2. Brown, D. E., and E. T. Bingham. 1994. Selfing in an alfalfa seed production field. Crop Sci. 34:1110-1112.
3. Jones, J. S. and E. T. Bingham. 1995. Inbreeding depression in alfalfa and cross-pollinated crops. In Plant Breeding Reviews. Vol. 13. p. 209-233.
4. Kalton, R. R., D. E. Brown, P. Richardson, and J. Shields. 1984. Advanced generation performance of narrow-based alfalfa varieties. P. 67 In Rep. of 29^th alfalfa Improvement Conf., Lethbridge, Alberta, Canada.
5. Kehr, W. R. 1976. Cross-fertilization of alfalfa as effected by genetic markers, planting methods, locations and pollinator species. Crop Sci. 13:296-298.
6. Kehr, W. R. 1976. Cross-fertilization in seed production in relation to forage yield of alfalfa. Crop Sci. 16:81-86.
7. Kehr, W. R., and G. R. Manglitz. 1976. Performance of certified seed lots of Dawson alfalfa. Nebraska Agric. Exp. Stn. Res. Bull. 277.
8. Knapp, Eric E., and L. R. Teuber. 1993. Outcrossing rates of alfalfa populations differing in ease of tripping. Crop Sci. 33:1181-1185.
9. Pedersen, M. W. 1967. Cross-pollination studies involving three purple-flowered alfalfas, one white florered line, and two pollinator species. Crop Sci. 7:59-62.
10. Pedersen, M. W. 1968. Seed number and position in the pod in reaction to crossing in alfalfa. Crop Sci. 8:263-264.
11. Veronesi, F., and F. Lorenzetti. 1983. Productivity and survival of alfalfa hybrid and inbred plants and competitive conditions. Crop Sci. 23:577-580.

The Origin of ‘Cossack’ Alfalfa

Melvin D. Rumbaugh

Humboldt, NE

The origin of Cossack alfalfa as described by Rumbaugh (1979) is correct. Professor V. R. Williams of the Imperial Agricultural College in Moscow collected the wild germplasm from which the cultivar was developed. There can be no doubt that N. E. Hansen obtained the seedstock from Professor Williams in 1906 (Hansen 1912). Excellent descriptions of the ‘Cossack’ and ‘Cherno’ accessions were included by Hansen on pages 78 to 82 of his 1913 Bulletin entitled "Cooperative Tests of Alfalfa From Siberia and European Russia". In this section he discussed naturally occurring hybridization between Medicago falcata L. and M. sativa L. and then stated the following:

"In 1910 I named two of these three Russian hybrid alfalfas, the Cossack and Cherno, both of them descended from single plants found wild by Prof. V. R. Williams, Imperial Agricultural college at Moscow, in the steppes of Voronesh province of southern Russia, the land of the Don Cossacks. As near as can be judged, they combine the good qualities of both parents.

The original plant of Cossack, S. P. I. 20714, as found wild in the dry steppes, had blue flowers on one branch, yellow on another, and sometimes both colors on the same branch.

The original plant of Cherno., S. P. I. 20716, as found growing wild, was described as a beautiful plant, very hardy, very productive and with black green flowers."

Hansen included similar descriptions in a number of his other publications. The best of these was printed in 1912.

HANSEN’S CHERNO ALFALFA

This is my No. 196 of the 1906 trip (S. P. I. 20716). A Sand Lucern or hybrid alfalfa (Medicago media) descended originally from a single plant found wild on the steppes of the Voronesh province, southeastern Russia, land of the Don Cossacks. The flowers are called black-green, but are really a very dark purple changing to a rich green with dark purple veins; plant of strong, very upright growth, a heavy seeder here the past three years. In my opinion this hybrid condition of the plant should be continued and the colors not isolated by selection as it appears to add extra vigor.

Cherno refers to the dark-colored flowers, being the Russian word for "black". Of course, as a matter of experiment, I am isolating single plants of both Cherno and Cossack.

HANSEN’S COSSACK ALFALFA

This is my No. 194 of my trip (S. P. I. No. 20714). A sand Lucern (Medicago media), a hybrid alfalfa from the Voronesh or Voronezh province of the Don river region of southeastern Russia. This spontaneous or natural hybrid of M. falcata and M. sativa will sometimes have blue flowers on one branch, yellow on another, sometimes both colors on the same branch; a heavy seeder the past three years. This stock descended originally from a single plant growing wild and in my

opinion this hybrid condition should be continued and the colors not isolated by selection as it appears to add extra vigor.

Rumbaugh (1979) wrote that Cherno and Cossack were merged and that the result retained the name, ‘Cossack’. Hansen documented this, although in a publication that probably was not widely distributed in states other than South Dakota. The following description of ‘Cossack’ was included on the third and fourth pages of an untitled circular authored by N. E. Hansen in his capacity as "Secretary South Dakota State Horticulture Society" and published by the Department of Horticulture, South Dakota State College of Agriculture and Mechanic Arts, Brookings, South Dakota, on February 26, 1918.

Cossack Alfalfa

----------

1916 CROP, 1,000 BUSHELS SEED

The Strongest and best one of these hybrid alfalfas is the one I have named Cossack, noted in bulletins 159 and 167. The Cherno Alfalfa, sister plant of the Cossack, has been consolidated with the Cossack as it is not possible to distinguish between them. The small spoonful of seed which I brought from Russia in 1906 and named Cossack has been developed in the hands of many farmers so that the 1916 crop in the western part of South Dakota was fully One Thousand bushels. In 1917 the crop of seed was reduced by crickets and grasshoppers. Buyers for the leading seedsmen have been busy in these fields and the seed is now being offered. Many farmers have found by their own experience that Cossack is the heaviest and best seeder of any alfalfa they have ever tested. Seedsmen are ready to handle many car loads more as soon as available. The dry seasons of 1911, 1912, 1913, demonstrated the value of Cossack. Very favorable reports of the Cossack come from many sections, including the far north west prairie region of Saskatchewan, Canada. We have only a few pounds of Cossack seed available for the special experimenters who wish to get their start from the original stock. Price, $2.00 per pound.

Our Cossack plants are only half size this year because the seed got planted too thick, hence they are priced accordingly. Plants, one pound, (Containing about 100 plants,) 30 cents; 10 pounds for $2.00.

Therefore, when first distributed to growers, Cossack was descended from a single M. falcata x M. sativa hybrid plant as stated by Barnes, et al. In 1977. In later years, Cossack, was the result of the merger of Cherno with the original Cossack. Seeds of both versions of the Cossack cultivar were not distinguished from each other in commerce and various small seed lots probably were composited prior to retail sale. Since Cherno and Cossack were nearly identical in origin and performance, growers and scientists apparently accepted the merger without comment.

References

Barnes, D. K., E. T. Bingham, R. P. Murphy, O. J. Hunt, D. F. Beard, W. H. Skrdla, and L. R. Teuber. 1977. Alfalfa Germplasm in the United States: Genetic Vulnerability, Use, Improvement, and Maintenance. USDA Agricultural Research Service Tech. Bul. 1571.

Hansen, N. E. 1912. Some New Fruits Originated by N. E. Hansen in the Fruit Breeding Laboratory of the South Dakota Agricultural Experiment Station and some new alfalfas found in Northern Eurasia by N. E. Hansen. South Dakota State College of Agriculture and Mechanic Arts.

Hansen, N. E. 1913. Co-operative Tests of Alfalfa from Siberia and European Russia. South Dakota State College of Agriculture and Mechanic Arts Bul. 141. Pp. 1-157.

_______. 1916. Untitled publication. South Dakota State Horticultural Society. Brookings, South Dakota.

Rumbaugh, M. D. 1979. N. E. Hansen’s contributions to Alfalfa Breeding in North America. South Dakota A. E. S. Bulletin B 665. Pp. 1-11.

My Observations about a Century of Breeding and Selection in the Alfalfa Genome

Donald K. Barnes

USDA, ARS-Retired

8307 Miner Road

Minocqua, WI 53548

The development of alfalfas adapted to the Midwest and Northern Great Plains began with the introduction of winterhardy germplasm into South Dakota, Minnesota, and Ontario Canada. The Minnesota source had the greatest impact because the farmer (Wendelin Grimm) conducted recurrent selection for winterhardiness during about 40 years. The superiority of the Grimm strain was documented in 1900 by Dr. Hays at the University of Minnesota. Authentic seed lots of Grimm still perform very well in the upper Midwest when pests, especially bacterial wilt, are not a problem.

Between 1900 and about 1950 most recognized Midwest cultivars were improved selections from one of seven introductions. The three most notable exceptions were "Atlantic", "Ranger" and "Narragansett", which were developed by combining germplasms from three or more sources. These varieties served as prototypes for variety development in the 1950's and 1960's. Narragansett had outstanding winterhardineess, but lacked bacterial wilt resistance and high seed yield potential. Atlantic, a synthetic variety with six germplasm sources, was a variety ahead of its time. Unfortunately Atlantic was hampered by lack of consistent seed production. Ranger had moderate bacterial wilt resistance and it was the first alfalfa variety with high seed yield and an organized seed distribution system. The success of Ranger’s bacterial wilt resistance and its seed production program paved the way for tht release of "Vernal," which was a synthetic variety with four germplasm components. Ranger and Vernal became the industry standards for many years.

During the 1950's and 1960's Medicago falcata germplasm from N.E. Hanson’s early 1900's explorations were being studied at South Dakota State University. Likewise Ladak germplasm was being evaluated at the Universities of Minnesota and Montana State. Chilean germplasm was being evaluated at Kansas State University and Turkistan germplasm was the basis for much of the Nebraska breeding program. The Cornell breeding program studied a broad range of germplasms and the crosses between germplasm sources. Northrup King & Co. introduced the first Flemish cultivar, "Du Puits", into the U.S. in 1947. Other Flemish introductions followed. The Flemish cultivars had excellent vigor and recovery after cutting and foliar disease resistance, but they lacked winterhardiness and resistance to many root diseases. The Cornell program released the cultivar "Saranac" which combined the bacterial wilt resistance from "Ranger" with the Flemish growth habit. By 1970 most new Midwest adapted cultivars had some Flemish germplasm in their parentage.

All nine-alfalfa germplasms sources (Medicago falcata, Ladak, M.varia, Turkistan, Flemish, Chilean, Peruvian, Indian, and African) introduced into the U.S. had both good and detrimental traits. Each time a new combination of germplasms was developed it usually meant that some undesirable traits needed to be bred out of the population. An example of linkage problems associated with breeding for multiple traits was demonstrated when David Beard at WL Research screened about 15,000 plants of Saranac for resistance to the spotted alfalfa aphid. Only six resitant plants were recovered and all of those plants had phenotypes similar to Saranac’s non-recurrent parent line from Ranger. Similar problems occured when Flemish sources of resistance to Verticillum wilt were integrated with adapted U.S. alfalfa populations. It was necessary to conduct several cycles of selection for Verticillium resistance. It was also necessary to select for resistance to bacterial wilt, Fusarium wilt, anthracnose and Phytophthora root rot. The Flemish germplasms were generally susceptible to those important U.S. diseases.

The Southern Corn Leaf Blight epiphytotic caused plant breeders to review the germplasm vulnerability of all major crops. It was determined in 1977 that alfalfa was less vulnerable to genetic disaster than it had been 50 years earlier. However the extensive use of the nine recognized germplasm resources suggested that new germplasm sources would be necessary for future improvements in alfalfa. This stimulated efforts to collect new germplasms from most alfalfa growing areas of the world.

The national Medicago germplasm collection is presently maintained at the U.S. Plant Introduction station, Pullman, WA. During the last 20 years the perennial collection has increased in size, seeds of all accessions were increased under cage isolation , and essentially all accessions were evaluated for resistance to pests and growth habit traits. The annual medic collection was also increased and made available for scientific research.

Establishment of the present U.S. Medicago germplasm collection represents the combined efforts of many people. Many of those who were most instrumental in organizing the collection have retired. It is now the responsibility of a new cadre of scientists to insure that the collection is maintained in a viable condition for future U.S. and world scientists to use. During the 25-year development of the present collection there were many heated discussions. There were suggestions that included throwing away the annual medics, combining all accessions into a small number of germplasm pools, and increasing seed of each accession by open pollination. These suggestions and others like them were discussed and dismissed. The guiding philosophy was that no one could know what germplasm would be useful in the future. It was therefore necessary to retain all introductions as individual accessions. Many suggestions were considered for establishing some type of pre-breeding program to increase the usefulness of the collection. (Note: Sorghum breeders are backcrossing day neutral and dwarfness genes into the world sorghum collection.) Unfortunately no viable plan could be agreed upon.

During the last 50 years I have observed that many alfalfa-breeding studies were conducted with less than the most appropriate germplasm. It is important that sufficient effort be given to the selection of germplasm with appropriate pest resistance, adaptation, and germplasm origin. Public germplasm populations may not always contain the best combimation of traits. Therefore it may often require establishing cooperative studies with industry breeders.

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