Genetic analysis of seed yield and oil content in safflower using F1 and F2 progenies of diallel crosses

Improvement of seed yield and oil content in safflower (Carthamus tinctorius L.) as an oilseed crop is the main objective of its breeding programs. However, little genetic information is available for these traits. The main objective of this study was to estimate genetic parameters for seed yield and oil content. Six safflower lines each derived from different Iranian local populations and Saffire as a foreign cultivar were crossed in all combination as a diallel set without their reciprocals. Crosses were selfed to obtain seeds of F2 progenies. F1 and F2 progenies along with their parents were evaluated in two separate experiments to do F1 and F2 diallel analysis. The GCA mean squares were significant for all traits including seed yield per plant, heads per plant, seeds per head, 100-seed weight, days to flowering, plant height and oil content. In both analyses, positive GCA effects for seed yield were found for parental lines IUTE1449 and IUTH13, indicates that progeny with those genotypes as parents showed seed yields that were greater than the average of all crosses. The parental line IUTKH211 was the best combiner for developing genotypes with high oil content. For achieving genotypes with short time to flowering and plant height, Saffire was the best parent. GCA/SCA ratio indicated there were large additive effects for all the traits, except for seed yield per plant. Narrowsense heritability for seed yield per plant and oil content was 9.3 and 23.5%, receptively. However, seeds per head, 100-seed weight, days to flowering and plant height had moderate to high narrowsense heritability (79.8, 55.4, 65.6 and 89.4%, respectively). There was reasonable consistency for estimating genetic parameters from analysis of F1 and F2 progenies.