Abstract
Eight varieties of cotton (Iranean, Gord 26, Lachata, CA22, Line106, Pima, Chirpam 539 and Coker 310) and their non reciprocal diallel crosses were planted through 2nd half of April, 2007 at field crops dept. farm, Tikrit University using randomized complete block design with three replications. Heterosis (deviation of F1 from mid parents), variances and effects of general and specific combining abilities were estimated for characters: plant height, number ho fruiting branches, number of nodes to first fruiting branch, number of opened bolls, boll weight and seed cotton yield per plant. The results showed that the hybrids (Iranean x Gord 26), (Iranean x Pima), (Gord 26 x Pima), (CA22 x Coker 310) and (Line106 x Pima) had significantly desirable midparent heterosis for a larger number of characters. Mean square due to genotypes, parents, hybrids, general and specific combining abilities was highly significant for all studied characters. Additive genetic variance was preponderant in the inheritance of all characters. The genotypes Lachata, Coker 310 and line106 and crosses (Iranean x Gord 26), (CA22 x Coker 310) and (Line106 x Pima) exhibited significant desirable gca and sca effects respectively for a larger number of characters, and were found to be the best general and specific combiners, and could be used for future breeding programmes.
Main Subjects