Identification of superior parents and hybrids from diallel crosses of bread wheat (Triticum aestivum L.)

Five parents of bread wheat (triticum aestivum l.) viz. td-1,skd-1,marvi,moomal and mehran were crossed in a half diallel design; hence 10 f,hybrids were developed. parents alongwith hybrids were evaluated for combining ability and heterosis for tillers/plant,spike length,spike density,grains/spike,grain yield/plant and seed index. the experiment was conducted in a randomized complete block design with four replications at botanical garden,department of plant breeding & genetics,sindh agriculture university,tandojam,during 2010. the analysis of variance due to genotypes,parents,hybrids and parents vs. hybrids was significant for all the characters which revealed presence of significant amount of genetic variability in the material. the results also indicated significant differences among the parents for their general combining ability (gca) and hybrids for specific combining ability (sca) suggesting the importance of both additive and non-additive genes in the expression of traits studied. the greater magnitude of sca variances over gca were recorded for tillers/plant,grains/spike and grain yield/plant which indicated the importance of additive gene action while the involvement of non-additive genes was evident in the inheritance of spike length,spike density and seed index. among the parents,generally td-1,mehran,moomal and marvi were the best general combiners for tillers/plant,spike length,spike density,grains/spike,grain yield/plant and seed index. whereas,the hybrids like skd-1 × mehran,marvi × mehran,marvix moomal and td-1 × skd-1 were the best specific combiners for majority of yield traits. positive heterosis was expressed by the hybrid skd-1 × moomal for tillers per plant; td-1 × moomal for spike length; td-1 × skd-1 for grains per spike; marvi × mehran for spike density and marvi × moomal for seed index. the best parents and hybrids could be effectively utilized in hybridization and selection programmes and also for hybrid crop development,respectively.