Genetic analysis for yield and yield contributing variables in upland cotton

Abstract

A diallel analysis of F 1 crosses involving six upland cotton genotypes to evaluate the population’s genetic potential, and genetic effects involved in the inheritance of yield and yield contributing traits was conducted during 2009 and 2010 at the University of Agriculture, Peshawar, Pakistan. The adequacy of the additive-dominance model was fully adequate for plant height and partially suitable for other variables. Larger values of dominance (H 1 , H 2 ) than additive (D) genetic components of variation showed that traits were primarily governed by non-additive gene action. Unequal proportions of positive (U) and negative (V) alleles in loci (H 2 <H 1 ) with asymmetrical distribution of genes was observed in the parents (H 2 / 4H 1 <0.25 and F was different from zero) for all the variables. The ratio of H 2 /4H 1 was below than maximum value (0.25) for all variables, which arises when U=V=0.5 over all loci. Broad sense heritabilities were higher; however, most of the variables manifested desirable medium narrow sense heritabilities with perceptible genetic gain. Negative correlation between Wr + Vr and parental means (y) for plant height, bolls plant -1 , boll weight and lint %, and positive correlation for seed cotton yield, indicated that parents containing dominant and recessive genes, respectively were responsible for their increased mean values. The F 1 hybrids of cultivars CIM-473, CIM-554, CIM-506 viz., CIM-473 × CIM-554, CIM-506 × CIM-554, CIM554 × CIM-707 and their reciprocals showed best performance for seed cotton yield and its contributing variables. These F 1 hybrids could be used for hybrid cotton; however, the desirable narrow sense heritability indicates that selection would be effective in early segregating generations.