1. Seedway 9558 was a cross of two plant populations: 1 ) Iroquois-type of germplasm sources labeled at Cornell as B x A, crossed onto Oneida VR; this population went through several cycles of phenotypic recurrent selection for multiple disease resistances, followed by one cycle of phenotypic selection for root regeneration capability, and 2) a population from multiple sources mostly related to Oneida VR that also went through several cycles of phenotypic recurrent selection for multiple disease resistances; followed by one cycle of phenotypic selection in the field for plant vigor, freedom of diseases, resistance to lodging, and lower forage neutral detergent fiber and acid detergent fiber concentrations; and one cycle of phenotypic selection for root regeneration capability. The population cross was done by hand, using a mixture of pollen from one population to cross onto each clone of the other population (95 clones per population). Seed of the Syn 1 generation was a bulk of equal weight of seed per clone from each of the two populations. The Syn 2 generation (breeder seed) was produced in 1995.
2. Seedway 9558 is adapted for the East Central region and intended for use in the Northern USA and Southern Canada for hay, haylage, greenchop, and dehydration. It has been tested throughout New York.
3. Seedway 9558 is a dormant variety with fall dormancy similar to the FD 3 check. Flower color of the Syn 2 generation is 80% purple, l % cream, trace yellow, l9% variegated, and trace white. Forage quality (NDF and RFV) is most similar to the high quality check. Values for ADF were of medium quality, in between the high and low quality checks.
4. Seedway 9558 has high resistance to bacterial wilt, Fusarium wilt, Verticillium wilt, and anthracnose (Race 1); resistance to Phytophthora root rot; and is susceptible to spotted alfalfa aphid, and Aphanomyces root rot (Race 1).
5. In 1995, breeder seed (Syn 2) was produced under cage isolation in Caldwell, ID, in sufficient quantity to last the lifetime of the variety. This seed is maintained under controlled environmental conditions by the Department of Plant Breeding at Cornell University. Foundation seed (Syn 3) may be produced from breeder seed in Northern USA on stands no more than 3 years old unless by consent of the breeder. Certified seed (Syn 3 or 4) may be produced from breeder or foundation seed on stands no more than 6 years old.
6. Certified seed was first marketed in 2001.
7. Application for Plant Variety Protection will not be made.
8. This information may be forwarded to the PVP office.
9. Variety Name: Seedway 9558 Date submitted: December 3, 2002
Experimental designations: NY9558