Location: Sunflower Research
Project Number: 5442-21220-028-19
Start Date: Jul 01, 2011
End Date: Jun 30, 2014
Sunflower hybrids and advanced experimental lines with expected resistance or tolerance to Sclerotinia head rot will be solicited from sunflower seed companies and breeding programs. Two sets of screening nurseries will be developed, one to screen new hybrid lines that have not been publicly evaluated and another set of hybrids to confirm the resistance that was previously defined. The new hybrid lines will be compiled into the “initial screening” which will include about 75 entries and be planted at Carrington, ND, and Morden, Manitoba. The most promising hybrids identified in initial screenings conducted in 2010 will be compiled into the “repeat screening” which will include about 25 entries. The “repeat” test will be planted at Carrington, Langdon, and Oakes, ND; Morden, Manitoba; and Crookston, MN. In all screenings, each hybrid will be established in plots one-row (30-inch) wide by 25 ft long and arranged in a randomized complete block with four replications. Sunflower heads will be inoculated with ascospores at the R5 growth stage (flowering). To accommodate differential development within and among hybrids, inoculations will be made on multiple days. Misting systems will be constructed, and misting will be initiated at flowering and continued as necessary to promote disease. Sunflower head rot incidence and severity will be scored at a minimum of two timings, and approximately 15 heads will be assessed per plot.