Genetic Variability and QTL Mapping for Seed Germination Characters under Water Stress in Sunflower

The objective of this research was to study the genetic control of germination variables under normal and water deficit conditions in sunflower. A population of 100 recombinant inbred lines obtained from a cross between PAC2 and RHA266 was used in the present study. The experiment was performed as a randomized complete block design with three replications. Germination variables were time to starting germination (TSG), time to maximum germination (TMG), time to 50% germination (T50%G) and percentage of seed germination (PSG). The putative causes of variation in germination, oil content (OC) and 1000 grain weight (1000GW) were also measured. Positive correlations were obtained between different times to germination for normal and stress conditions. Positive correlations were observed between PSG and OC, as well as between 1000 GW and the different times to germination. Several non-specific QTLs to water deficit were detected for germination parameters. “HA1837”, “SSL27“and “ORS671_1” were the SSR markers associated with QTLs detected for germination characters independent of germination environments. The most important specific QTL was associated with “ORS677” SSR marker in the water stress condition, explaining 24% of the phenotypic variance for PSG.