GENETIC BEHAVIOR FOR SOME QUANTITATVE CHARACTERS

Abstract

Three crosses of upland cotton were carried out between SP8886 and each of the varieties, Lachata, Cocker310 and Dunn1047, and F1, F2, B1 and B2 generations of each cross were obtained. The six generations of each cross were tested in an experiment using randomized complete block design with three replications to study the genetic behavior for seed cotton yield per plant and some of its components. Generation mean analysis (least square method) was used with two models to estimate additive, dominance and epistatic effects, the first with three parameters (additive-dominance model) and the second with six parameters (additive-dominance-interaction model), and χ2 – test used to determine the fitness of the first model for characters: seed cotton yield per plant, plant height, number of fruiting branches, number of bolls per plant, boll weight and lint index. The results showed that the first model was adequate for most of the studied characters in the three crosses, therefore epistasis was not important in the inheritance of these characters except plant height in the cross (Lachata x SP8886) and seed cotton yield per plant in the cross (Cocker310 x SP8886). Dominance gene effects were relatively more important than additive effects in the inheritance of the most of studied characters. Narrow sense heritability estimates were varied from 17.441% for seed cotton yield per plant in the cross (Cocker310 x SP8886) to 69.999% for number of fruiting branches in the cross (Lachata x SP8886). The results also revealed the presence of positive heterosis and inbreeding coefficient for the most of the studied characters in the three crosses.المصادر