Eight sesame (Sesamum indicum L.) genotypes were crossed in a half diallel mating fashion. The analysis of variance for combining ability revealed that the mean sum of squares are due to the general combining ability were highly significant for all the traits. The t 2 test specified the fulfillment of assumptions required under diallel analysis for all the traits studied except the number of effective branches per plant, capsule length (cm) and harvest index (%). The component D measures the additive effects of genes. It was significant for all the traits except seed yield per plant and harvest index. The components H 1 and H 2 were significant for all the traits except days to maturity revealing the importance of fixable and non-fixable component. Greater values of H 1 than H 2 and the ratio of H 2 /4H 1 (< 0.25) confirmed the unbalanced distribution of gene at the loci in the parents' implying dominance for all the traits. It was also confirmed by greater than one value of KD/KR components for all the traits which suggested the higher frequency of dominant genes than recessive genes in the parents. The component F was significant for days to flowering, days to maturity, capsule length, oil content and leaf area per plant. The graphical analysis showed the regression line intercepted Wr axis below the origin indicating over dominance for plant height, the number of seed per capsule, oil content and leaf area per plant. The regression line intercepted the positive side of Wr axis for days to maturity which implies the presence of partial dominance.

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The phenomenon of heterosis has provided the most important genetic tools in improving yield of crop plants. Identification of specific parental combination capable of producing the highest level of heterotic effects in F1 has immense value for commercial exploitation of heterosis. The experimental material consisted of eight parents (including check G.TIL 4) and their 28 half-diallel crosses. The analysis of variance revealed highly significant differences due to genotypes for all the traits. On the basis of mean values, the parents G.TIL 10, G.TIL 4 and SKT 1607 recorded maximum seed yield per plant. G.TIL 10 was top ranking for number of effective branches per plant. This parental genotype also expressed good performance for various yield components, viz., number of seed per capsule, harvest index (%) and oil content (%).The parent SKT 1608 found better for earliness, dwarfness and 1000 seed weight (g). While in case of hybrids, SKT 1608 × SKT 12-2, SKT 1608 × G.TIL 2 and SKT 1607 × G.TIL 2 were the best for seed yield per plant. Among the 28 F1 hybrids, SKT 1608 × SKT 12-2 and SKT 1608 × G.TIL 2 manifested significant positive heterosis for seed yield per plant over better parent and standard check (G.TIL 4) These two crosses also exhibited either of the significant positive heterosis for various component traits viz., plant height (cm), capsule length (cm), number of seed per capsule, harvest index (%), 1000 seed weight (g), oil content (%) and leaf area per plant (cm2).