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A line x tester analysis using 10 lines and five testers were carried out to study the stability of 50 hybrids over environments using three different sowing dates for seed cotton yield and its quantitative traits in cotton. The analysis of variance for stability revealed significant differences among the genotypes for all the characters when tested against the pooled error and pooled deviation. The mean square due to environments (E) was also found significant when tested against the pooled error and pooled deviation for all the characters. G x E interactions were non-significant for all the characters except days to 50% flowering, days to 50% boll bursting, seed index and oil content indicating linear response of different genotypes for various traits under varied environmental conditions. The variance due to environments (linear) was significant for all the traits when tested against pooled error as well as pooled deviation. The stability parameters viz., overall mean (X), regression coefficient (bi) and deviation from regression (S2di) revealed that the hybrids G.Cot 18 x GSHV 173, G.Cot 18 x GTHV 7/70, G.Cot 12 x GTHV 7/70, G.Cot 12 x G.Cot 20 and GJHV 511 x GSHV 173 were the most widely adapted and stable crosses for seed cotton yield per plant and its components. The parents GJG 101, Deviraj, G.Cot 12, G.Cot 10, GJHV 500, GJHV 511, GJHV 517, GJHV 521, GJHV 536, Suraj, G.Cot 20, GSHV 173 and GTHV 7/70 were identified as the stable genotypes for seed cotton yield and its components and hence, they may be utilized in breeding programmes for incorporation of stability in cotton. [ABSTRACT FROM AUTHOR]

A study was conducted in castor (Ricinus communis L.)to assess the extent of heterosis over environments for twelve quantitative traits including seed yield per plant. Four pistillate lines and 13 monoecious lines were crossed in a line x tester fashion to develop 52 F1 hybrids. The pooled analysis of variance over environments showed significant differences among the environments (Sowing dates) for all the characters except number of capsules on primary raceme indicating wide variation in environmental conditions or differential expression of traits under different sowing dates. The mean square due to parents, hybrids and parents vs. hybrids were also found significant for all the characters, indicating the presence of sufficient amount of genetic diversity in the material for the twelve traits studied. Heterosis was worked-out over better parent and standard check, GCH-7. Significant desired heterobeltiosis ranged from -37.14 to 75.95% and standard heterosis ranged from -61.77 to 18.64% for seed yield per plant. However, magnitude of heterosis was found to vary substantially from cross to cross and character to character. The crosses JP-89 x PCS-124, JP-89 x RG-2826, SKP-84 x 48-1, SKP-106 x 48-1 and SKP-106 x PCS-124 were the best heterotic combinations for seed yield per plant, which recorded 75.95, 70.45, 61.11, 60.45 and 58.57 % heterobeltiosis, respectively. The heterosis for seed yield per plant was associated with the heterosis expressed by its component characters. [ABSTRACT FROM AUTHOR]

A line x tester analysis using six lines and eleven testers was carried out to study the combining ability and gene action for grain yield and 14 quantitative traits in pearl millet. Analysis of variance for combining ability revealed that significant differences among the mean squares was observed for lines, testers and lines x testers for all the characters except for mean squares due to lines for number of productive tillers per plant, ear head weight per plant, grain yield per plant, harvest index and threshing index and due to testers for ear head weight per plant, days to maturity, dry fodder yield per plant, grain yield per plant, harvest index and threshing index, which indicated the importance of both additive and non-additive genetic variances in the expression of these characters. The ratio of GCA variance and SCA variance indicated the predominance of non-additive gene action for the characters days to 50% flowering, length of protogyny, number of nodes per plant, plant height, number of productive tillers per plant, ear head weight per plant, days to maturity, 1000-grain weight, dry fodder yield per plant, grain yield per plant, harvest index and threshing index and additive gene action for ear head girth and ear head length. Among the lines, ICMA-04111, ICMA-92777 and ICMA-05333 and the testers J-2534, J-2454 and J-2507 displayed high gca effect for grain yield per plant and for some desirable traits. Significant and positive sca effect for grain yield per plant was displayed by the cross ICMA-05333 x J- 2527 followed by ICMA-05333 x J-2340, JMSA-20064 x 283-SB-11, ICMA-92777 x STPT-115, ICMA-04999 x J-2539 and JMSA-20071 x J-2507. These crosses involved either average x average, good x poor, poor x poor or good x good general combining parents. These crosses have been identified as best hybrids for improving grain yield per plant and could be further evaluated to confirm their stable superior performance. [ABSTRACT FROM AUTHOR]

A line x tester analysis using 12 lines and three testers was carried out to study the combining ability and gene action in sesame for seed yield and 14 quantitative traits. Analysis of variance for combining ability revealed significant differences among the mean squares due to lines, testers and lines x testers for all the characters except oil content, which indicated the existence of genetic diversity among the parents and hybrids. General and specific combining ability variances showed the involvement of both type of gene actions in the inheritance of these characters. Among the lines, IC-81564, NIC-75, Borda-1 and among testers, G.Til-10 were good general combiners for seed yield per plant and some of its contributing traits. The cross combination, IC-81564 x G.Til-10 showed significant and positive sca effect for seed yield per plant and involved good x good combining parents. It was followed by AT-238 x G.Til-10, NIC-75 x G.Til-4, TNAU-12 x G.Til-4, Keriya-2 x G.Til-3 and Keriya-2 x G.Til-10 which involved either good x good, good x poor or poor x poor combining parents. These crosses have been identified as best hybrids for improving seed yield per plant and could be evaluated under different environment to confirm their superiority. [ABSTRACT FROM AUTHOR]