Inheritance of Sclerotinia Midstalk Rot Resistance in Elite Sunflower Breeding Germplasm NonCommercial-NoDerivatives 3.0 License. (CC BY-NC-ND 3.0) Publication History

Abstract Sclerotinia sclerotiorum (Lib.) de Bary is a yield-limiting factor and the major disease of sunflower (Helianthus annuus L.) in the temperate regions of the world. In this study, we characterized resistance to S. sclerotiorum midstalk rot and morphological traits in a population derived from a cross between two Sclerotinia resistant lines. Phenotypic data for 114 F3:4 lines and the two parents, NDBLOSsel and K04, were obtained under artificial infection in field experiments which yielded moderate to high heritabilities. Our results suggest that S. sclerotiorum resistance is highly quantitative and that different genomic regions may mediate the resistance in different tissues of the plant. We found transgressive segregation for all three resistance traits suggesting that both resistant parents carried complementary QTL. In addition, we investigated the segregation of two known QTL for midstalk resistance and found that one of them also acts as a major QTL in this cross between two resistant lines. Collectively, our results suggest that a QTL stacking approach is a promising way to increase resistance to S. sclerotiorum in elite sunflower germplasm