Insights from gene effects on agronomic, oleic acid and oil content using generation mean analysis in sunflower (Helianthus annuus L.)

Plant hybridization produces hybrids with desirable traits such as high oil content, oleic acid and yield, enhancing the significance of crops. Understanding genetic dominance is essential for studying gene action in breeding programs. Using four parental lines, this study assessed gene action, genetic advance with heritability and heterosis for oleic acid, oil content, agronomic and yield traits in sunflowers. The IR6 × HO-5-29 (P1 × P2) cross I population demonstrated superior performance, while the CMSB825B × COSF6B (P3 × P4) cross II population also performed well based on mean performance. Generation mean analysis revealed that additive and dominance gene actions influenced trait inheritance, with dominance effects being more pronounced. Additive × additive interactions played a key role in traits like days to flowering and maturity, palmitic acid content and oleic acid content in cross I and head diameter in cross II. Additive × dominance interactions significantly influenced head diameter, 100-seed weight and oleic acid content in cross I and plant height in cross II. Dominance × dominance interactions strongly influenced seed and oil yield per plant, oil content and linoleic acid content in cross I and seed and oil yield per plant and volume weight in cross II. Duplicate gene action was observed for head diameter and 100-seed weight, whereas complementary gene action was observed for seed and oil yield per plant in both crosses. These findings offer valuable insights for plant breeders and farmers, supporting the development of sunflower varieties and hybrids with enhanced oleic content, oil content and yield.