Genetic analysis of seed yield, oil content and their components in safflower (Carthamus tinctorius L.).

The genetic architecture of seed yield, oil content and their components was studied in a diallel cross of F1 and F2: eleven parents, representing an adequate diversity for all considered characters in safflower were used. Combining ability analysis revealed the predominance of gca variance for plant height, total capitula, seed weight, seed number and seed yield in F1 and F2 generations and for days to flowering and oil content in F1. The analysis of components of variance indicated that the non-additive factor was the major influence on total capitula and seed yield in F1s, and F2s, and on plant height, seed weight and seed number in the F2 alone. The heterogeneity of the dominance component over generations has been attributed to coupling phase linkage. All four Indian parents, namely S 144, A1, MS 49 and 6 spl, together with G 1157 and US 104 in the exotic group, were the best combiners for seed yield and/or for one of its components while the remainder of the exotic parents were characterized by high gca effects for oil content. VFstp 1 and Frio were the only parents approximating both properties of oil content and seed yield. Breeding methods, such as biparental mating followed by reciprocal recurrent selection, were suggested for the simultaneous improvement of seed yield and oil content.