Assessment of genetic variability and correlation analysis of seed and seed cotton yield attributing traits of tetraploid cotton genotypes (G. hirsutum L.)

Abstract

The nature and magnitude of genetic divergence, variability and correlation were estimated in 110 extant varieties of cotton using Mahalanobis D 2 statistics by considering 20 quantitative characters to reveal a considerable amount of diversity in the material. The genotypes were grouped into ten clusters. Cluster I constituted a maximum number of accessions (80). The genotypes falling in cluster VIII (32.329) had the maximum divergence, which was closely followed by cluster IX (28.032), cluster X (23.674) and cluster I (15.717). The inter cluster distance was maximum between cluster VIII and IX (45.242) suggesting that the genotypes representing these clusters may be used as parents for future crop improvement programme. Traits like yield per plant, number of bolls per plant, sympodial length, number of sympodia per plant, dry matter of seedlings and plant height were the major contributors for genetic divergence. ANOVA revealed the presence of considerable amount of variability among the genotypes. High estimates of the genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were observed for yield per plant, number of bolls per plant, sympodial length, number of sympodia per plant, dry matter of seedlings and plant height. High heritability coupled with high genetic advance as per cent of mean was recorded for yield per plant, number of bolls per plant, dry matter of seedlings, sympodial length, number of sympodia per plant, plant height, speed of germination, shoot length, boll weight per plant, vigour index and fibre fineness. In correlation analysis, seed cotton yield was significant and positively correlated with number of bolls per plant followed by boll weight, plant height, seed index and fibre length. Hence, selections based on the above characters will result in genotypes with high seed cotton yield.