Cotton (Gossypium hirsutum L.) is a vital cash crop in Pakistan, but climate change scenarios threatened its production by biotic and abiotic stress, especially drought. Nutrient management, specifically potassium (K) fertilization, typically alleviates the effects of drought. To this end, a greenhouse experiment evaluated the genotypes for drought stress tolerance and its management by K fertilization. The experiment consisted of 70 cotton genotypes factorially combined with two water levels (standard irrigation and drought stress) and two potassium levels (control and 102 mg/kg of potassium). Data collection occurred for shoot and root lengths, fresh shoot and root weights, dry shoot and root weights, root shoot ratio, total dry matter production, and K uptake after 45 days of germination. Results depicted that mean squares for genotypes, drought, potassium, and their interaction were significant for shoot and root lengths, fresh shoot and root weights, dry shoot and root weights, total dry weight, and potassium uptake, while some traits showed nonsignificant differences. Based on the principal component analysis, membership function value, and genotypic diversity, five genotypes emerged as tolerant: CIM-496, IR-3701, Cp-15/2, FH-113, and CIM-1100, and three, i.e., 4-F, MNH-129, and FH-1000, as susceptible. Tolerant and susceptible genotypes can further benefit breeding programs to develop cotton genotypes adaptable to drought stress and with better K uptake.
Cotton (G. hirsutum L.), drought, potassium, PCA, cluster, the membership function value
The five upland cotton (Gossypium hirsutum L.) genotypes, CIM-496, IR-3701, Cp-15/2, FH-113, and CIM-1100, performed better for potassium uptake under drought stress conditions. The three susceptible genotypes were the FH-1000, 4-F, and MNH-129.