Abstract
Searching crop cultivars resilient to environmental stresses is crucial for mitigating the adverse effects on global agricultural production. Our study aimed to identify semiarid-adapted cotton cultivars exhibiting high performance under water restrictive conditions. The trials were conducted in a greenhouse employing a completely randomized design, in a 6 × 4 factorial scheme, consisting of six cotton cultivars (FM 911 GLTP, FM 912 GLTP RM, FM 970 GLTP RM, FM 974 GL, FM 978 GLTP RM, FM 985 GLTP) subjected to four water levels (100, 80, 60 and 40% field capacity - FC). At 20 days post-drought imposition, cotton plants exhibited reduced growth and gas exchanges under 60 and 40% FC compared to plants from 100 and 80% FC treatments. All cultivars displayed poor physiological and growth performance at 40% FC. Under 60% FC, FM 970 and FM 985 showed superior dry biomass, leaf area, and growth, indicating the highest drought tolerance. Conversely, although FM 911, FM 912, and FM 978 displayed higher rates of net photosynthesis, transpiration, stomatal conductance, and photosynthetic pigment content under 60% and 40% FC, they exhibited increased lipid peroxidation. Additionally, FM 911, FM 970, and FM 974 had the lowest osmotic potential values. In conclusion, water levels at 60% and 40% FC represent moderate and severe drought conditions for cotton crops, respectively. The superior performance of FM 970, FM 978, and FM 985 is attributed to pigment accumulation and photosynthetic efficiency, making them promising cotton cultivars for cultivation in water-scarce regions.