Climate change could be an existential threat to many crops. Drought and heat stress are becoming harder for cultivated crops. Cotton in Pakistan is grown under natural high temperature and low moisture, could be used as a source of heat and drought tolerance. Therefore, the study was conducted to morphological, physiological and molecular characterization of cotton genotypes under field conditions. A total of 25 cotton genotypes were selected from the gene pool of Pakistan based on tolerance to heat and drought stress. In field trail, the stress related traits like boll retention percentage, plant height, number of nodes and inter-nodal distance were recorded. In physiological assessment, traits such as photosynthesis rate, stomatal conductance, transpiration rate, leaf temperature, relative water content and excised leaf water loss were observed. At molecular level, a set of 19 important transcription factors, controlling drought/heat stress tolerance (HSPCB, GHSP26, HSFA2, HSP101, HSP3, DREB1A, DREB2A, TPS, GhNAC2, GbMYB5, GhWRKY41, GhMKK3, GhMPK17, GhMKK1, GhMPK2, APX1, HSC70, ANNAT8, and GhPP2A1) were analyzed from all genotypes. Data analyses depicted that boll retention percentage, photosynthesis, stomatal conductance, relative water content under the stress conditions were associated with the presence of important drought & heat TF/genes which depicts high genetic potential of Pakistani cotton varieties against abiotic stress. The variety MNH-886 appeared in medium plant height, high boll retention percentage, high relative water content, photosynthesis rate, stomatal conductance, transpiration rate and with maximum number transcription factors under study. The variety may be used as source material for heat and drought tolerant cotton breeding. The results of this study may be useful for the cotton breeders to develop genotype adoptable to environmental stresses under climate change scenario.

气候变化可能对许多作物构成生存威胁。对栽培作物而言，干旱和热胁迫变得越来越困难。巴基斯坦的棉花生长在自然高温低湿条件下，可作为热源和耐旱性。因此，本研究对田间条件下棉花基因型的形态、生理和分子特征进行了研究。根据对高温和干旱胁迫的耐受性，从巴基斯坦基因库中选择了总共 25 个棉花基因型。在田间试验中，记录了铃保留率、株高、节数和节间距离等胁迫相关性状。在生理评价中，观察光合速率、气孔导度、蒸腾速率、叶片温度、相对含水量和离体叶片失水量等性状。在分子水平上，一组 19 个重要的转录因子，控制干旱/热胁迫耐受性（HSPCB、GHSP26、HSFA2、HSP101、HSP3、DREB1A、DREB2A、TPS、GhNAC2、GbMYB5、GhWRKY41、GhMKK3、GhMPK17、GhMKK1、GhMPK2、APX1 、HSC70、ANNAT8 和 GhPP2A1) 分析了所有基因型。数据分析表明，胁迫条件下的棉铃保留百分比、光合作用、气孔导度、相对含水量与重要的干旱和高温 TF/基因的存在相关，这描述了巴基斯坦棉花品种对抗非生物胁迫的高遗传潜力。品种MNH-886株高中等，留铃率高，相对含水量高，光合作用速率高，气孔导度高，蒸腾速率高，在研转录因子数量最多。该品种可用作耐热和耐旱棉花育种的原料。这项研究的结果可能有助于棉花育种者开发可在气候变化情景下适应环境压力的基因型。