This study evaluated the physiological and yield-related responses of 18 advanced upland cotton (Gossypium hirsutum L.) lines and the cultivar Namangan-77 under different water conditions. Significant differences were evident in total water content, transpiration rate, and yield traits across genotypes under optimal and water deficit environments. Lines L-1, L-29, and L-24 demonstrated lower sensitivity to drought stress for physiological and agronomic traits, suggesting their potential in breeding for drought tolerance. Correlation analysis indicated a weak relationship between leaf water content and transpiration rate under optimal water conditions, whereas under water deficit, a positive association appeared between leaf hydration and cotton weight per boll. Furthermore, under prolonged drought, a strong positive correlation between leaf water content and transpiration rate occurred, highlighting the importance of efficient water use. Lines L-2, L-24, and L-11 produced heavier seeds under optimal water supply, although drought significantly reduced seed weight and fiber yield in most genotypes. These findings contribute valuable insights for future cotton breeding programs targeting improved drought resilience and stable productivity.
Upland cotton (Gossypium hirsutum L.), water regimes, drought conditions, physiological traits, chlorophyll, carotenoids, morpho-agronomic traits
The identification of cotton (G. hirsutum L.) lines L-16 and L-23 was successful, exhibiting stability for transpiration rate in plant leaves under water deficit conditions. Consequently, they are beneficial as breeding material in developing drought-tolerant cotton genotypes. Among medium-fiber cotton lines, lines L-1, L-29, and L-24 showed less sensitivity to water deficit as compared with other lines for physiological and economic traits.