Abstract:
The present study was conducted to improve the genetic potential of sunflower related to oil and yield related traits in limited water supply. For breaking the present yield barrier and evolving varieties with high yield potential in low water availability, it is desirable to combine the genes from genetically diverse parents. Due to high heterosis occurring generally in hybrids between genetically unrelated inbred lines, all crop breeders that use heterosis have the challenge to find good combiners. The success in identifying such parents mainly depends on the gene action that controls the trait under improvement, combining ability and genetic makeup. The breeding material first screened for the water stress and then the ten tolerant line and five susceptible testers were selected. These selected parents were tested for genetic diversity by SSR primers and found two parents (A-10.8, G-60) showing 46.7% maximum genetic dissimilarity. This cross also showed positive desired heterosis over the mid for leaf area, number of achenes per head and achene yield per plant. Therefore, the lines A-10.8 and tester G-60 are best for further breeding program in the future, because these lines are more diverse. Most of the characters in the present study showed over dominance type of gene action and inbred lines are showing desirable negative and positive heterosis. Lines A-10.8, A-11 and tester G-60 followed by A-35 are showing positive heterosis for number of achene per head, 100-achene weight. A-11 and A-35 could be the potential parents for early maturity and short duration cultivar development. RL-51 and C-10 are good general combiners for oil content. While A-10.8 is consistent as good general combiner for achene yield per plant in both non-stress and stress conditions. Hybrid B-2.8 × B-3 showing desirable negative heterosis for early maturing and short duration for hybrid development. While hybrid A-10.8 × G-60 could be used as potential parents for short stature and high yielding hybrid seed development which are also proved to be genetically most dissimilar. These potential parents and outperforming crosses could be used in further breeding programs and will definitely cause a major cut to the import bill of edible oil in Pakistan. Moreover, results in non-stress and stress regime was not consistent for most of the characters which showed that breeding for drought is more reliable in the target environment. Valuable information regarding gene action, combining ability, heterosis were generated.
