Phenotypic and Genotypic Correlation Coefficients for Some Yield and Fiber Quality Traits of Segregating Populations (F2, F3 and F4) in Egyptian Cotton Crosses

The present study was undertaken with a view to determine the extent of relationship between seed cotton yield and other economic traits of F2, F3 and F4 generations in the two Egyptian cotton crosses i.e., the cross I [({Giza 89 x Giza 85} x {Giza 86 x Giza 81}) x ({Giza 83 x Giza 80} x Giza 89)] and the cross II [(Giza 85 x Giza 86) x ({Giza 83 x Giza 80} x Giza 89)]. The F2, F3 and F4 generations in the two crosses were grown at Sakha experimental farm, Cotton Research Institute, Agricultural Research Center, Egypt during 2008, 2009 and 2010 seasons, respectively. The mean squares obtained from analysis of variance showed highly significant (P≤0.01) differences for most studied traits of F2, F3 and F4 generations in the two crosses. For the two crosses, the best mean values for boll weight (3.27 and 3.39 g) and 2.5% span length (33.22 and 32.84 mm) traits in F4 generation, for seed cotton yield/ plant (175.88 and 197.09 g) and uniformity index (87.01 and 86.54%) traits in F3 generation and for fiber fineness (3.75 and 3.63) in F2 generation were found. While, lint percentage (40.68 and 41.39%) and fiber strength (10.32 and 10.44 g / tex) traits exhibited highest mean values of the crosses I and II in F4 and F3 generations, respectively. In general the magnitude of genotypic correlation coefficient was higher than those of phenotypic correlations coefficient of most studied traits for F2, F3 and F4 generations in the two crosses. Seed cotton yield for the two crosses exhibited positive and highly significant association with lint percentage, 2.5% span length, fiber fineness and fiber strength traits in F2 generation and with lint percentage and 2.5% span length traits in F3 and F4 generations, while, the correlation change for fiber fineness and fiber strength in F3 and F4 generations. 2.5% span length, fiber fineness, fiber strength and uniformity index for the two crosses in F2, F3 and F4 generations had a highly significant positive correlation with boll weight. Lint percentage showed positive and highly significant association with fiber fineness for F3 generation in the cross I and with fiber fineness and strength traits for three generations in the cross II. These results indicating that, the two crosses should be used in improving yield and fiber quality in Egyptian cotton.