1. SW 7400 is a 110 plant synthetic variety developed from a cross of two populations, SW 8210 and SW 7204 (WL 457 plant selections). Plants were cross pollinated in a cage using both honey bees and leaf cutter bees. Plants were selected from a seed production field trial at Mendota, California and a mature hay field near Chowchilla, California. Selection criteria included seed yield, plant vigor, fine stems, short internodes, and resistance to Fusarium wilt, spotted aphid and southern root knot nematode. Estimated germ plasm sources are: African (38%), Indian (18%), Turkistan (17%), Chilean (6%), Peruvian (6%), M. varia (4%), Flemish (2%), Ladak (1%), and unknown (8%).
2. SW 7400 alfalfa is adapted to areas in the Sacramento Valley and San Joaquin Valley of California where varieties of dormancy ratings 7 and 8 are grown. Yield tests are currently under way in California. Use is intended in the Sacramento and San Joaquin Valleys California.
3. Fall dormancy of SW 7400 is 7. Flower color is 99% purple and 1% variegated bloom and a trace of white bloom in the syn. 3 generation.
4. SW 7400 is highly resistant to Fusarium wilt, Spotted alfalfa aphid and Southern root knot nematode (M. incognita) and resistant to Phytophthora root rot, anthracnose, blue alfalfa aphid and pea aphid. It has moderately resistance to bacterial wilt, Verticillium wilt and stem nematode. SW 7400 was not tested for Aphanomyces root rot (race 1).
5. Breeders seed was produced in 1994. S & W Seed Company will maintain sufficient Foundation seed for the projected life of this variety. Under certification the classes of seed will be Breeder, Foundation and Certified. Foundation seed will be produced from Breeders seed and/or Foundation seed. Foundation seed will be used to produce Certified seed. Length of stand life allowed for Foundation and Certified seed is four and six years respectively.
6. Certified seed will be available for sale in the Fall of 1998.
7. Application will not be made for P.V.P.
8. This information can be sent to the P.V.P. office.
9. Variety: SW 7400 Date Submitted: November 1, 1997
Experimental designations: SW 7411 and SW 8411