581

1.   581 is a synthetic of 10 clones. Four clones trace to Lahontan type germplasm, 2 to Washoe, 3 to Caliverde 65, and 1 to N78 Brand. The clones were selected during a period of years from 1962 to 1971 based on agronomic characteristics and resistance to different insects and diseases. The clones were tested extensively before synthesis of the variety.

2.   581 has been tested for forage yielding ability in the San Joaquin and Sacramento Valleys of California and at Lowden, Washington. It is expected to be adapted where other semi-dormant, and slightly less dormant, alfalfas are grown. Primary purpose is for hay with additional usage for haylage, green chop, grazing, and de-hy.

3.   Flower color is purple. It is semi-dormant. It has high resistance to biotypes of the spotted alfalfa aphid found in the lower San Joaquin Valley and Las Cruces, New Mexico areas; moderate resistance to Phytophthora root rot, bacterial wilt and downy mildew. 581 has a low level of resistance to pea aphid. It is susceptible to anthracnose and its reaction to stem nematode is unknown.

4.   Seed classes of 581 will be breeder, foundation, and certified. Breeder seed is the bulk harvested polycross seed of the 10 parental clones produced under isolation. Certified seed may be produced on fields established with either breeder or foundation seed. No other class or generation is recognized as 581.

5.   Certified seed will be available in the fall of 1978.

6.   No application for Plant Variety Protection is being considered.