GENE ACTION AND HETEROSIS OF LINE X TESTER IN COTTON

The objective of this experiment was to facilitate the selection in cotton breeding and estimation of heterosis, the gene action and general combining ability (GCA) of the parents and specific combining ability (SCA) of hybrids considered for the development of high yielding in early generation. A field trial was carried out on the Field Crops Research Station of State Broad for Agric. Res. in Abu Ghraib. Line x tester analysis involving five cotton female lines (Makneer, 44200, Marsomi 5, 113,and Dise) and three testers (Lashata, Ashoor 1, and Cocker 310 wilt), were crossed in 2007. The eight parents and theirs 15 hybrids were planted in a randomized complete block design with three replications in 2008. Significant differences were found among genotypes (lines, tester, and crosses) in all traits studied. The hybrid Ashoor x Dise showed significant heterosis over best parent for seed cotton yield (70.8%), no. of total bolls (161.6%), and no. of open bolls (126.2%). The variances due to GCA and SCA were significant for all traits studied. This indicated that both additive and non-additive gene effects were responsible for the investigated characters. It was found that in the population, plant height, no. of total bolls, no. of open bolls, boll weight, and earliness were influenced by additive gene effects while seed cotton yield, no. of sympodia, and no. of monopodia were influenced by non-additive gene effects. Among the parents Ashur 1 for seed cotton yield, boll weight, and no. of sympodia and 44200 for seed cotton yield and plant height were detected with higher general combining ability. SCA was significant for Cocker 310 wilt x Makneer and Lashata x 44200 hybrid combinations for seed cotton yield.