Evaluation of Morphometric and Physiological Divergence Present in Cultivated Cotton Germplasm

Abstract

Cotton (Gossypium hirsutum L.) is a major fiber crop of Pakistan; however, its productivity has declined in recent years due to climatic stress, pest pressure, and limited genetic improvement. The present study was conducted to assess genetic diversity and identify superior cotton genotypes using multivariate statistical approaches. Eleven cotton genotypes were evaluated at the Cotton Research Station, Bahawalpur, under a randomized complete block design with three replications. Data were recorded for key agronomic, physiological, yield, and fiber quality traits, including plant height, number of nodes, monopodial and sympodial branches, green bolls, open bolls, net photosynthetic rate, ginning out turn, fiber length, and seed cotton yield. Analysis of variance revealed significant genetic variability among genotypes for most traits, particularly plant height, monopodial branches, net photosynthetic rate, fiber length, ginning out turn, and yield. Correlation analysis showed that seed cotton yield was strongly and positively associated with net photosynthetic rate (r = 0.95^**), open bolls (r = 0.80^**), number of nodes (r = 0.78^**), and plant height (r = 0.75^**), while a strong negative correlation was observed between yield and fiber length (r = –0.96^**), indicating a trade-off between yield and fiber quality. Cluster analysis grouped the genotypes into three distinct clusters, with Cluster-2 exhibiting superior performance for yield and yield-related traits. Principal component analysis explained 85.31% of total variation through the first three principal components, highlighting net photosynthetic rate, yield, and nodal traits as major contributors to genetic divergence. Overall, the study identified promising genotypes (VH-373 and BH-224) with high yield potential and provided useful selection criteria for cotton improvement programs.