HETEROSIS, COMBINING ABILITY AND STABILITY ANALYSIS FOR YIELD AND FIBRE QUALITY TRAITS IN UPLAND COTTON (GOSSYPIUM HIRSUTUM L.): A COMPREHENSIVE REVIEW

Abstract

Upland cotton (Gossypium hirsutum L.) is a globally important fibre crop, and improving seed cotton yield and fibre quality remains a primary objective of cotton breeding programs. Over the past decades, extensive research has focused on heterosis, combining ability, and stability analysis to identify superior parental lines and high-performing hybrids. This review critically synthesizes published studies employing classical biometrical approaches such as Line × Tester and diallel mating designs, multi-environment evaluations, and emerging molecular methodologies including transcriptomics, QTL mapping, and multi-omics integration. Previous investigations consistently demonstrate the involvement of both additive and non-additive gene action in controlling yield and fibre traits, while genotype × environment interaction significantly influences hybrid performance and adaptability. Although substantial progress has been achieved through conventional breeding, limitations persist in terms of restricted environmental testing, narrow genetic bases, and limited integration of molecular tools. Recent advances highlight the potential of combining phenotypic selection with genomic-assisted breeding to enhance selection efficiency and hybrid stability. This review further identifies key research gaps and outlines future directions emphasizing integrated breeding strategies, expanded multi-location trials, and utilization of diverse germplasm resources. Collectively, the synthesis provides a comprehensive framework for developing high-yielding, fibre-quality superior, and environmentally stable cotton hybrids to support sustainable cotton production.