Multivariate analysis of cotton (Gossypium spp) accessions for agro-morphological and fibre quality traits

Abstract

Genetic improvement of important agronomic, fibre yield and quality triats in cotton has been slow due to its narrow genetic base. Hence, the need to study and explore available  germplasm resources to assess the variation among the cotton germplasm and to classify and identify the potential genotypes that can be used in the development of hybrid with the best agronomic, fibre yield and quality traits.. One hundred cotton genotypes were evaluated from diverse sources in a 10 x 10 lattice design, replicated twice across two environments in 2022 wet season. Significant (p ≤ 0.05) genotypic variation was observed for plant height, number of sympodial branches, number of bolls, seed cotton yield and the degree of pest attack. Principal component analysis (PCA) indicated that four components explained over 99.5% of the total variation of the data, with PC1 and PC2 accounting for 86.5% and 10% of the total variability, respectively. PC1 was associated with most of the traits except stand count at emergence, whereas PC2 was related to stand count at emergence. Cluster analysis produced three clusters, cluster1 consisted of genotypes (n = 39) that had low values for most of the traits assessed except fibre fineness. Cluster 2 was composed of genotypes (n = 35) with high values of traits measured while cluster 3 had genotypes (n = 26) with the highest values of measured traits. Using rank summation index, genotypes VIR-7112-HG-69-15, VIR-7072, LA-213-SEA-ISLAND LEAF, BULGARIA-996 and 30858 with rank summation indices of 243, 270, 313, 330, 332 and 368 respectively were the best materials and potential genotypes for the development of hybrid with the best agronomic, fibre yield and quality traits, while LINIA-7010 ranked last with rank summation index of 712. It could be concluded that significant genetic variation exists for important agronomic and fibre quality traits like seed cotton yield, number of bolls, plant height, number of sympodial branches, fibre length and fibre fineness. Consequently, the selection of promising cotton genotypes based on the aforementioned traits will make genetic improvement further feasible.