1. Arc was developed by eight cycles of recurrent phenotypic selection. The first four cycles of selection were those of the variety TEAM. The fifth cycle was field selection of 120 plants for resistance to alfalfa weevil larval feeding damage. The sixth, seventh and eighth cycles were screened for anthracnose and bacterial wilt resistance. Seed produced from intercrossing plants selected in the final cycle was designated as Syn 1. Subsequent generations of such increase was designated Syn 2, Syn 3 and Syn 4. Breeders seed is the first generation increase from the Syn 1 designation MSHp6F-An4W4 produced at Prosser, Washington.
2. Arc is adapted to a considerable part of North Carolina, Virginia, Maryland and Southeastern Pennsylvania.
3. Flower color is predominantly purple and blue with a low frequency of variegated blossoms,variable in growth habit, similar to Team in fall and winter dormancy and upright growth habit. This variety has high resistance to anthracnose and pea aphid, moderate resistance to bacterial wilt and is slightly more tolerant to alfalfa weevil larval feeding than Team.
4. Seed increase shall be in the limited generation sequence with one generation each of Breeder, Foundation and Certified Classes. Production of Foundation seed will be in the Central alfalfa region and in Idaho, Oregon and Washington.
5. Certified seed class limited quantity probably available Fall 1974.
6. No decision on Plant Variety Protection Act.