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Study on the combining ability and gene action in sunflower through line × tester mating design

This study was conducted to evaluate gene action and combining ability for yield, agronomic traits through line X tester analysis with 36 hybrids, developed from nine testers and four lines. The experiment was conducted in randomized complete block design with three replicates for two years 2015-16 and 2016-17 at AICRP-Sunflower, Nimpith Centre. Gene action and combining ability for seed yield and other yield attributing agronomic traits were studied in the sunflower hybrids. The cytoplasmic male sterile lines were used as female lines while some new male inbreds were introduced as testers in the form of fertility restorers. The inbred lines and their F1hybrids differed significantly in their mean values of the traits under the present study. For each of the traits, highly significant positive and negative GCA values were recorded which was reflected from the hybrid combinations. Highly significant positive effects of the GCA for seed oil content were observed in the Rf-lines R-138-2, R-104 and EC-601978 and in Pet-89-1A. On the basis of analysis, SCA: GCA ratio variances indicated that the most of the total genetic variation for head diameter, oil content (%), seed yield per plant or seed yield in kg per hectare, volume weight (g/100 cc), 100 seed weight(g), 100 seed kernel weight, hull content and oil yield in kg per hectare were governed by the non-additive gene action or non-additive component of genetic variance had a more significant role in the inheritance of the above mentioned traits in the F1 hybrid combinations in sunflower. The study‟s results indicate that the additive as well as non-additive components had a more or less equal role for the inheritance of plant height trait in sunflower. Highly significant positive effects of the GCA for seed yield (kg/ha) were observed in the Rf-lines R-12-96, R-104, EC-601978 and R-630 and in Pet-2-7-1A and CMS-107A. For early maturity and semi-dwarfness, the best general combiners were CMS P-2-7-1A and CMS-10A and EC-601958 (restorer line). Five parents, R-104, R-12-96, EC601978, EC-601958 and P-2-7-1A exhibited positive high gca effect for seed yield and some other yield components like head diameter, 100 seed weight, volume weight (g/100cc) and oil %, therefore, these five parents could be adjudged good general combiners for high seed oil content as well as the high oil yielder sunflower hybrids in near future. It also depicted that the above genotypes appeared to possess high concentration of non-additive genes for seed yield and component traits. The results of this study may be used for the identification of new high yielding sunflower hybrids based on the hybridization between the best combiners.