GENETIC ANALYSIS FOR SOME YIELD AND FIBER QUALITY TRAITS USING F 2 AND F 3 POPULATIONS IN COTTON

The experiment was conducted at Agricultural Research Center Giza, Egypt during 2008 and 2009 seasons to estimate the genetic parameters for F 2 and F 3 generations in the two intra-specific crosses (G. 89 x G. 86) x Suvin and (G.89 x Pima S 6 ) x (G.75 x Sea Island). Observations were recorded on boll weight (g), seed cotton yield/plant (g), lint percentage (%), 2.5% span length (mm), fiber fineness, fiber strength and uniformity index traits. The analysis of variance for all traits studied manifested highly significant differences of F 3 generations in the two crosses, while, the F 2 generation exhibited highly significant for seed cotton yield/plant and uniformity index in the first cross, and boll weight, seed cotton yield/plant and uniformity index in the second cross. The traits, seed cotton yield, boll weight and lint percentage showed high phenotypic and genotypic coefficients of variations estimates for F 2 and F 3 generations in the two crosses. There is enough scope for selection based on these characters, and the diverse genotypes can provide materials for a sound breeding programme. High heritability coupled with high genetic advance and genetic advance as percentage of mean (genetic gain) observed for seed cotton yield/plant, boll weight and lint percentage of F 2 and F 3 generations in the two crosses showed that these traits were controlled by additive gene effects and phenotypic selection for these characters would likely to be effective. These results suggest that rigorous plant selection is required to identify desirable plants from F 2 and F 3 generation. Selection pressure is low in the F 2 and F 3 generations but increases in the F 4 generation for private breeders. fiber lengths in millimeter at 2.5 % span length (2.5 % S.L.), fiber fineness (F.F.), fiber strength (F.S.) and uniformity index (U.I.) in cotton ( G. barabadense , L.) were conducted in the Agricultural Research Center Farm, Giza, Egypt during 2008 and 2009 seasons. This study was set up on F 2 and F 3 generations of two crosses (G. 89 x G. 86) x Suvin and (G.89 x Pima S 6 ) x (G.75 x Sea Island). Selected plants in F 1 generation were self-pollinated for the two crosses. Seeds harvested from those self-pollinated plants constituted the F 2 seed. The F 2 seeds were sown and care was taken to maintain the population size of 100 plants in each cross combination. Self pollination was done in the selected plants of F 2 generation for advancing them to F 3 generation based on their superiority in previous biometrical traits. The F 2 generation consisting of 100 individuals and F 3 generation was raised along with the parents during 2008 and 2009 seasons, respectively. The experimental design used in the two seasons was a randomized complete blocks design (RCBD) with three replications. The parents were grown in two row plots and the F 2 's were raised in 10 rows and F 3 's in 5 row plots. Each row was 4 m long and 0.60 m wide. Hills were spaced at 0.40 cm and thinned at one plant per hill. Selected plants in each single plant progeny were observed and their biometrical and fiber quality traits were recorded. All the