QTL mapping of protein content and seed characteristics under water-stress conditions in sunflower

The purpose of this study was to identify genomic regions controlling seed protein content, kernel and hull weights, and seed density in water-stress conditions in sunflower (Helianthus annuus L.). The experiments consisted of a split-plot design (water treatment and recombinant inbred lines) with three blocks in two environments (greenhouse and field). High significant variation was observed between genotypes for all traits as well as for water treatment x genotype interaction. Several specific and nonspecific QTLs were detected for all traits under well-watered and water-stress conditions. Two SSR markers, ORS671_2 and HA2714, linked to protein content were identified that have no interaction with water treatments in greenhouse conditions. We also detected the E35M60_4 marker associated with kernel weight that had no interaction with water treatments. A specific QTL for protein content was detected with important phenotypic variance (17%) under water-stress conditions. Overlapping QTLs for protein content and seed density were identified in linkage group 15. This region probably has a peliotropic effect on protein content and seed density. QTLs for protein content colocated with grain weight traits were also identified.