Genetic variability and association studies in BC₃F₁ population of sunflower (Helianthus annuus L.)

Variability and association studies for oil yield and its component traits were investigated in BC3F1 population of a cross between IR6 (recurrent parent with low oleic acid content) and HO5-29 (donor parent with high oleic acid content). Among 12 traits studied, volume weight (g/100 ml) , head diameter (cm), oil yield per plant (%), seed yield per plant (g), oleic acid (%), linoleic acid (%), palmitic acid (%), and stearic acid (%) displayed high phenotypic coefficient of variation and genotypic coefficient of variation along with moderate or high heritability and genetic advance as a percent of mean. This suggests that these traits are mainly under the control of additive gene action. Hence, selection based on these characters could significantly improve these traits in this population. The traits such as days to flowering, 100-seed weight (g), and stearic acid (%) have shown a platykurtic distribution which represents that these characters are amenable for selection towards further improvement. Correlation analysis showed that positive correlation between oil yield per plant and all traits, except with days to flowering. Path analysis on seed yield indicated that head diameter alone had a high positive direct effect and other traits had low direct effects. Hence, selection for head diameter can improve the seed yield in sunflower.