Identification of retrotransposon-based (IRAP) loci associated with resistance to Sclerotinia stem rot disease (Sclerotinia spp.) in sunflower

Sclerotinia disease is important fungal disease of sunflower in Iran that reduces its growth and yield. In this study, reactions of 100 oily sunflower lines to 6 fungal isolates of Sclerotinia were studied and then 128 retrotransposon-based molecular markers (IRAP) were used to identify genes controlling disease resistance. The results showed that there is high diversity in the studied germplasm for resistance to the Sclerotinia stem rot. Population structure analysis subdivided the studied lines into 3 subpopulations (K=3). Association analysis with general and mixed linear models (GLM and MLM) identified 14 and 11 loci, respectively that are significantly associated (P≤0.01) with Sclerotinia disease resistant genes. Markers LTR 106365, LTR 1064-65 and LTR 1062 were commonly associated with resistant to some fungal isolates. The common markers due to facilitating simultaneous selection for resistance to several fungal isolates can be well used in sunflower breeding programs like marker-assisted selection (MAS).