Study of Combining Ability and Gene Action for Seed Yield in Sunflower (Helianthus annuus L.) Using Line x Tester Analysis

Abstract

The choice of suitable parental lines is vital in crop improvement programs, as the performance of the resulting hybrids reflects their relative advantages. Therefore, selecting parents with strong combining ability is a key component in the success of any breeding effort. A study was undertaken to assess the extent of heterosis and combining ability in sunflower using six cytoplasmic male sterile (CMS) lines and seven restorer lines, crossed in a line × tester mating design during the Kharif 2024 season. The resulting hybrids were evaluated in the Rabi 2024–25 season at the Oilseeds Research Station, Latur. Observations were recorded for ten agronomic traits, including days to 50% flowering, days to maturity, plant height, head diameter, seed filling percentage, 100-seed weight, volume weight, hull content, oil content and seed yield per plant. Among the female lines, CMS-82A exhibited significant GCA effects for days to 50% flowering, seed filling percentage, volume weight, hull content and oil content, whereas CMS-852A was found to be a strong general combiner for seed yield per plant, oil content and seed filling percentage. Among the male lines, LT-02 showed favorable GCA for days to 50% flowering, head diameter, seed filling percentage, hull content, oil content and seed yield per plant. LT-07 also emerged as a promising general combiner for days to 50% flowering, seed filling percentage, 100-seed weight, volume weight, hull content, oil content and seed yield. LT-01 was specifically identified for its strong GCA for seed yield. Notable hybrids with significant SCA effects for seed yield and other desirable traits included CMS-112A × LT-02 and CMS-10A × LT-05. These crosses exhibited Specific combining ability (SCA) variance that was greater than general combining ability (GCA) variance for all the studied traits, indicating the predominance of non-additive gene action in trait expression. Thus, the study confirms that utilizing parents with high GCA and selecting crosses with favorable specific combining ability (SCA) effects is an effective approach for evolving superior sunflower hybrids.