Abstract
North Carolina designs are very effective in breaking undesirable linkage and lead to creating genetic variability in a population. F1 population was obtained by crossing the four varieties were used to produce two crosses (Giza 93 × Menofy) and (G.96× C.B58). The F1 seeds for each cross were planted in order to obtain the seeds of F2 generation through self-pollination. F2 seeds were used as a material for this study. The analysis of variance was highly significant for all studied traits for genotypes for the two crosses. Also, the males were significant for all studied traits except position of ball node (PFN), boll weight (BW) g/plant, micronaire value and fiber strength for cross I, but in cross II males sets were significant for all studied traits, which exhibit difference between them except position of ball node (PFN), aboll weight (BW) g/plant and seed index (SI) which showed difference between them.Mean squares due to females within males were significant for all studied traits except duration of boll maturation, boll weight, micronaire value and fiber strength in cross I and position of ball node (PFN), boll weight (BW) g/plant and seed index in cross II. The contribution of male or female parents was more pronounced in the genetic variation. Additive components of variation were higher than dominance ones for most studied traits reflecting decreased (√D/A) values (less than unity). While the dominance portion of the genetic variation played a role for some traits reflecting higher (√D/A) values. In biparental progenies which confirmed by high mean genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) values. The variation created on account of biparental mating was found to be heritable as seen from increases of discrepancy between (PCV) and (GCV) and reflected less influence of environmental factors
Keywords
Cotton, North Carolina, Biparental mating, PCV, GCV, Genetic variance