Unravelling the Genetic Basis of Fusarium Wilt Resistance and Abiotic Stress Tolerance in Cotton

Abstract

Cotton (Gossypium hirsutum L.), often referred to as ‘white gold’, is a vital global crop, yet its productivity and fibre quality are significantly affected by abiotic stressors like drought and salinity, as well as biotic threats such as Fusarium wilt (Fusarium oxysporum f. sp. vasinfectum). To enhance stress tolerance, disease resistance and fibre quality, this study employs marker-assisted selection (MAS) as a more efficient alternative to conventional breeding. Genomic DNA from eight cotton genotypes, including hybrids and varieties, was analysed using polymerase chain reaction (PCR) with molecular markers (BNL1604, Gh247, BNL3255, JESPR220, SOC1 and CAT) linked to economically significant traits. Results indicated that the BNL1604 marker (102 bp allele) was associated with fibre quality in most samples, while the Gh247 marker (125 bp allele) suggested additional genetic influences on fibre characteristics. The BNL3255 marker (225 bp allele) was consistently linked to Fusarium wilt resistance, whereas the JESPR220 marker showed allele variation. The SOC1 gene, related to early maturation, exhibited polymorphism but failed to amplify in the Kamolot-79 variety. Stress tolerance variability was reflected in fragment size differences of the CAT gene, associated with abiotic stress resilience. These findings highlight the significance of molecular markers in accelerating cotton improvement through MAS, enabling the development of high-yield, disease-resistant and stress-tolerant cultivars. Future research should focus on validating these markers across broader genetic populations to optimise their use in cotton breeding programmes.