Breeding and Quantitative Genetics Advances in Sunflower Sclerotinia Research

Brent Hulke, Zahirul Talukder, Lili Qi and Thomas Gulya Jr.

Abstract: In 2009, we continued the process of backcrossing the head rot QTL from the HA 441 x RHA 439 population into confectionery and elite oilseed backgrounds BC1F1 hybrids were produced and we are in the process of selecting progeny based on their marker profiles at 6 major QTL loci for advancement into another backcross. Our efforts to perform association mapping with the 260 Plant Introductions (PIs) obtained from the North Central Regional Plant Introduction Station of USDA-ARS in Ames, IA, are moving forward. We have added two more locations of data with two replications each to the data set we formed last year with Tom Gulya’s sister project. We have recently completed the analysis of both the 2008 and 2009 data. Based on the distribution of data, which is more broadly and normally distributed than we were expecting, we believe that the phenotypes will be adequate for mapping using the association mapping model. We are currently working on developing the marker set for our resistance candidate genes using in silico techniques and resequencing of ESTs, which will contribute the necessary genotypes with which we can complete our association model. Our traditional breeding program had a successful season in 2009, with breeding lines in the F4 to F7 selfing generations being tested for Sclerotinia head and stalk rots, each at two locations. Our goal here is to continue introgression of new, minor resistance loci from many domesticated sources into elite germplasm.

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