1a. Objectives (from AD-416)
Monitor the location-specific variation in scab resistance of potato breeding material and newly released cultivars by field testing (national trials).
1b. Approach (from AD-416)
A total of 20 newly-released potato cultivars and advanced breeding selections plus four popular cultivars as checks (Atlantic, Ranger Russet, Russet Burbank, and Superior) will be tested in common scab nurseries in four locations, embodying a range of environmental conditions and different pathogen populations. Locations are in Aberdeen, ID, Becker, MN, E. Lansing, MI, and University Park, PA. A randomized complete block with three replications of four hills will be planted for each clone. At harvest, each tuber will be rated for percent surface area covered with lesions and type of lesion. Data from cooperating sites will be analyzed by our investigator. The resulting comparison and ranking of susceptibility to predominant Streptomyces isolates will be made available to growers to help them select the most scab-resistant cultivars for their region.
3. Progress Report
The most effective control for potato common scab is the use of potato varieties resistant to the disease, and potato breeders routinely test their newly developed lines in field trials to establish levels of susceptibility or resistance to the disease. In 2010, 22 potato varieties selected by potato breeders from 6 breeding programs in the U.S. were tested for common scab in 4 field locations which differ in soil and environmental conditions and in the bacteria responsible for the disease. Statistical analysis of the data from the tests is ongoing, but quick comparison of the tested potato breeding lines with resistant and susceptible standard check varieties shows that breeders selections are more scab-resistant than the susceptible varieties in all locations. Common scab is one of the most important potato diseases in the upper Midwest and northeastern United States, and the results of field-testing common scab resistance will be used to by potato growers to choose common-scab resistant varieties. Progress by University of Minnesota collaborators was monitored by regular exchange of e-mails and receipt of a preliminary written report containing experimental results.