ESTIMATION OF GENETIC COMPONENTS BY USING NORTH CAROLINA MATING DESIGN SYSTEM FOR DETECTION DESIRABLE GENE ACTION IN COTTON.

North Carolina design system is very effective in breaking undesirable linkage and lead to creating genetic variability in a population. One population was obtained by crossing two cultivars Giza 88 (G.88) and TNB1 followed by intermitting between each F₂ plants with original parents G.88 and TNB1. The results of the analysis of variance indicated that significant and highly significant mean squares for all the studied traits and these results indicating there were differences between them. The contribution of male or female parent was more pronounced in the genetic variation of the cross. The additive genetic variance was higher than dominance variance for most of the studied traits and potence ratio were less than one for these traits .On the other hand, the dominance portion of the genetic variation played the major role for inheritance of the other traits. Heritability in broad sense was larger than heritability in narrow sense for all the studied traits and the correlation coefficient was positive and significant between some of pair traits. These results recommended by recurrent selection for improvement of most the studied traits. While, many cycles of intermitting would dissipate the negative correlation.