1. One hundred plants were selected in 1963 from a 2-year-old stand of Sonora alfalfa in which a high percentage of the plants showed severe symptoms of infection by the alfalfa mosaic virus. Selection was based on freedom from stunting and chlorosis. Nine clones highest in general combining ability for forage production were used as parents of Sonora-70.
2. Adapted to the lower desert valley areas of southern Arizona where the variety Sonora is well adapted. It will be used for hay, greenchop or pasture production.
3. Purple flowers and darker green foliage than Mesa-Sirsa. Pubescence and uniformity are similar to Sonora. Very nonwinter dormant and upright in growth habit. Sonora-70 is intermediate between Mesa-Sirsa and Sonora in resistance to four biotypes of the spotted alfalfa aphid.
4. An equal amount of polycross seed from each of the nine parent clones will be blended and classed as breeder seed. Breeder seed will be used to establish fields for the production of foundation seed. Foundation seed will be used to establish fields for the production of certified seed. Breeder and foundation seed will be grown in lower desert valley areas of southern Arizona. There will be no registered class. Only breeder, foundation and certified seed may be called Sonora-70.
5. Fall of 1971.