Utilization of wild species for diversifying the cytoplasmic male sterility source of sunflower (Helianthus annuus L.) hybrids

The present investigation is directed at improving sunflower using hybrids having diverse cytoplasmic male sterile (CMS) sources from Helianthus annuus and H. argophyllus. The aim is to develop and identify promising lines and hybrids with a high combining ability and to obtain highly productive oilseed sunflower hybrids having diverse CMS sources. Five diversified CMS lines and 10 testers were crossed in a line × tester mating design to develop 50 F₁ hybrids for genetic analysis. The pooled analysis of variance revealed significant differences among hybrids for the traits studied. The mean squares of lines and testers from crosses and GCA variance components revealed the prevalence of additive variances and additive gene action. The mean squares of lines × tester interactions were also significant for all the traits considered. The significance of lines × tester interactions and SCA variance components indicated that SCA is also important in the expression of traits and demonstrated the role of dominant and epistatic genes in controlling the various traits. Among the diverse CMS lines, ARG-6-3-1-4was identified as the best general combiner for stem diameter, volume weight, seed yield, hull content and oil content. While, the line ARG-2-1-2 was the best general combiner for days to 50 per cent flowering, head diameter, 100 seed weight and seed filling per cent. The tester M17-R was observed to be the best general combiner for earliness and volume weight, while RHA 93 was the best general combiner for plant height, seed yield and oil content. The crossMUT-2-8-3-2 × GKVK 3 was found to be a good specific combiner for stem diameter, 100 seed weight, seed yield, seed filling percentage and oil content while, ARG-6-3-1-4 × GKVK 3 was a good specific combiner for days to 50% flowering, plant height and 100 seed weight. The highest standard heterosis for seed yield was observed in the hybrid MUT-2-8-3-2 × GKVK 3 followed by ARG-2-1-2 × LTRR 822 while for oil content the highest was seen in the cross ARG-6-3-1-4 × RHA95-C-1 and thus these hybrids can be exploited for sunflower improvement and diversifying the cytoplasmic male sterile sources of this valuable oilseed crop.