Estimate of Genotypic Variance and Covariance Components In Some Egyptian Cotton Genotypes

ESTIMATE OF GENOTYPIC VARIANCE AND COVARIANCE COMPONENTS IN SOME EGYPTIAN COTTON GENOTYPES EL-ADLY.H.H AND A.E.M. EISSA Cotton Research Institute, Agricultural Research Center, Giza, Egypt ABSTRACT Twenty genotypes were grown in five locations in 2009 season to study variance components, in addition to heritability, genetic advance under selection, genetic coefficient of variability and genotypic and phenotypic correlations for some agronomic traits. The results indicated that mean squares of the genotypes were highly significant for seed cotton yield (SCY), lint yield (LY) and boll weight (BW). Environments mean squares were highly significant for all studied traits except for lint index (LI). Genotypes-environment interaction mean squares were highly significant for seed cotton yield (SCY), lint yield (LY) and lint percentage (L %) and significant for boll weight (BW). Genotypic variances (?2 g) and (?2 e) are generally of high amount for seed cotton yield (SCY), lint yield (LY) and boll weight (BW) and generally small for lint percentage (L %), seed index (SI) and lint index (LI). Large amount of genotype-environment interaction variances (?2 ge) were found for seed cotton yield (SCY), lint yield (LY) and boll weight (BW). The ratios of ?2 g/?2 ge were low for all studied traits. Low heritability estimates in broad sense (h.b.s %) (Less than 30%) were computed for all traits. The expected genetic advance at 5% (G.S %) intensity of selection ranged from 1.80 for lint index (LI) to 11.01 for lint yield (LY). Positively significant genotypic and phenotypic correlations were found between seed cotton yield (SCY) and both lint yield (LY) and boll weigh (BW), Lint yield (LY) and lint percentage (L %), boll weight (BW) with seed index (SI), lint percentage (L %) with lint index (LI) and seed index (SI) with lint index (LI).