Combining Ability and Heterosis Studies in Sunflower (Helianthus annuus L.)

Abstract

Sunflower is an important oilseed crop, and the development of productive hybrids depends on the identification of suitable parental lines and superior cross combinations. The present investigation was carried out to identify the best general combiners among the parental lines and hybrids with good specific combining ability and heterosis for yield and its component traits. The study evaluated four cytoplasmic male-sterile lines, six fertility restorer lines and 24 experimental hybrids during Kharif 2024 at the Regional Agricultural Research Station, Nandyal. The analysis of variance showed a significant line × tester interaction for all traits except plant height. Among the lines, NDCMS 30A was identified as the best general combiner for days to 50% flowering, 100-seed weight and seed yield. Among the testers, NDI 55 was identified as the best general combiner for days to 50% flowering and seed yield. Among the hybrids evaluated, NDCMS 30A × NDI 55 and CMS 234A × NDI 36 recorded significant specific combining ability effects for 100-seed weight and seed yield. Furthermore, the heterosis estimates of 24 hybrids for yield traits revealed that NDCMS 30A × NDI 55 and CMS 148A × NDLR 32 showed significant positive heterobeltosis and standard heterosis for seed yield. The study revealed that NDCMS 30A × NDI 55, CMS 234A × NDI 36 and CMS 148A × NDLR 32 were promising in terms of specific combining ability and heterosis and may be further exploited for the development of inbred lines and the improvement of hybrid vigour in sunflower.