Screening for drought tolerance using physiological traits in upland cotton (Gossypium hirsutum L.)

Climate change patterns indicate a serious threat to freshwater availability for crops. A selection of drought-tolerant genotypes is essential for breeders. Three key physiological parameters of abiotic stress: relative water content, excised leaf water content, and cell membrane stability were assessed with 68 upland cotton genotypes in Pakistan. The most tolerant and susceptible genotypes were evaluated in a greenhouse under controlled conditions. From the selected genotypes, heat and drought stress-related transcription factors were screened and included the following: GhNAC2, DREB2A, GhABF2, HSC70, HSFA2, GbMPK3, GbMpK17, GhMKK1, APX1, GHSP26, TPS, ANNAT8, GhMPK2, GhMKK3, GhWRKY41, HSPCB, HSP101, HSP3, GhPP2A1, and GbMYB5. Cell membrane stability may be a screening criterion for drought tolerance in cotton under field and greenhouse conditions. Under these conditions, the physiological and molecular analyses revealed that the genotypes CRIS-134, BH-184, and FH-114 were the most tolerant, and the genotypes CIM-240, CIM-446, and FH-900 were susceptible. The selected tolerant varieties can be recommended for cultivation in drought-prone areas. They can be used in future breeding programs for drought tolerance in cotton.