Estimating combining ability of yield and its components in upland cotton through line x tester analysis

Combining ability estimates are very important genetic attributes to cotton breeders in predicting improvement that could be envisaged from hybridisation and selection programmes. the crosses were attempted in a line x tester mating design,which involved five female and three testers,hence 15 f1 hybrids were developed. the experiment was carried out in a randomised complete block design with four replications. the mean squares due to general combining ability (gca) of lines and testers and specific combining ability (sca) of lines x testers interactions were significant,for all the characters studied. the significance of gca and sca variances suggests that both additive and non-additive genes were controlling the characters,yet additive genes of female lines were predominant because their variances were generally,higher than gca of testers and sca of lines x testers. among the lines,parents cim-506,cris-134 and sadori and from testers,bt-cotton and sindh-1 exhibited higher gca effects hence proved to be the best general combiners for most of the traits studied. results further suggested that these potential parents can reliably be used in hybridisation and selection programmes for extracting desirable plants from segregating populations. the f1 hybrids like sadori x sindh-1,chandi x bt-cotton and sadori x bh-160 were best specific combiners for earliness (bolls formation and opening at 90 and 120 days after planting),bolls per plant,boll weight,seed cotton yield per plant,lint % and staple length. the performance of f1 hybrids per se was very well reflected in sca effects,conferring the potentiality of f1 hybrids.