Performance of scab resistant potato varieties in western Nebraska

Summary

• 1. Three late varieties, Ontario, Menominee and Cayuga, produced fewer scabby potatoes than any other of the commercial varieties tested during two years in a number of dryland and irrigated tests in western Nebraska. Because of grade inferiorities, due to rough and immature tubers, they are of promise for commercial production on only a limited number of irrigated farms where scab is usually very prevalent. On dryland the same defects occurred, but the yields of US#1-A size potatoes averaged higher than with the commonly grown Triumph.

• 2. Scab was more prevalent with Yampa and Russet Sebago than with the previously mentioned varieties. However, both appeared of dubious commercial value for irrigation — Yampa, because of hollow heart, growth cracks and sun-greened tubers and Russet Sebago because of immaturity, one aspect of which was spotted russeting. On dryland Yampa tubers were of reasonably good quality with the average production of U.S. # 1 tubers being greater than with any of the other varieties, but Russet Sebago was least productive.

• 3. Progress appeared to be the most desirable of the varieties in this test for western Nebraska, because the tubers possessed a red skin color with a relatively low incidence of mild types of scab, were free from harvest cracks, and made a pleasing market appearance with good table quality. In fields where scab was very severe Progress, at times, showed less scab than Russet Sebago.

• 4. Triumph produced a higher percentage of scabby tubers with more scab of severe types than any of the varieties in these tests.

• 5. The average specific gravity of tubers was higher with all these varieties than with Triumph.