VS-550
(Experimental Desig.)
1. VS-550 is a synthetic variety which was developed by strain crossing and phenotypic recurrent selection for resistance to Verticillium wilt, Phytophthora root rot, anthracnose, or the blue alfalfa aphid. Parentage traces predominately to Valley +, Baron, Emerald, Crown, CUF 101, WL 315, and DK-135. Estimates of the major germplasm sources that constitute this variety are: M. falcata (3%), Ladak (4%), M. varia (10%), Turkistan (11%), Flemish (43%), Chilean (10%), Peruvian (1%), Indian (4%), African (7%), and unknown (7%).
2. VS-550 is intended for use in the Sacramento Valley and similar high desert valleys of California, Nevada, Idaho, Arizona, and New Mexico for hay, haylage, or dehy production. VS-550 has been tested in California, New Mexico, and Idaho.
3. VS-550 is a moderately winter variety with fall dormancy similar to DuPuits. Flower color is approximately 90% purple, 9% variegated, and 1% cream.
4. VS-550 has high resistance to the spotted alfalfa aphid and Fusarium wilt; resistance to pea aphid, blue alfalfa aphid, Phytophthora root rot, and anthracnose; and moderate resistance to Verticillium wilt. Reactions to bacterial wilt and stem nematode are unknown.
5. Seed increase of VS-550 is on a limited-generation basis with one generation each of breeder and certified seed classes, and up to two generations of foundation seed. Breeder seed (Syn 1), foundation seed (Syn 2 or Syn 3), and certified seed (Syn 3 or Syn 4) classes will be recognized. Breeder seed (Syn 1) was produced under cage isolation near Woodland, CA in 1985. Sufficient foundation seed for the projected life of this variety will be maintained by Vista. Production of Syn 3 foundation seed requires consent of the breeder. Stands of foundation and certified seed fields are limited to 3 and 6 years, respectively.
6. Certified seed of VS-550 will be available in 1989.
7. No decision has been made regarding Plant Variety Protection (PVP).
8. This information can be forwarded to the PVP office.