RELATIONSHIP BETWEEN WATER EXCHANGE AND  PHOTOSYNTHETIC PARAMETERS OF COTTON VARIETIES

Ulugmurodova Yulduz

Authors

Ulugmurodova Yulduz Samarkand State University

Keywords:

cotton, extreme, conditions, physiology, biochemistry, correlation, strees

Abstract

This article examines the responses of cotton varieties and breeding lines to extreme climatic conditions based on physiological and biochemical indicators obtained from field and laboratory experiments conducted in 2024 in the Payariq district of the Samarkand region. The following varieties and breeding lines were investigated: Zarafshon, Omad, Bukhara, Afsona, Gulshan, C-278, Sultan-R1, UzFA, as well as Ridge-1, Ridge-2, and Ridge-3. During the study, plant water exchange, total leaf water content, water-holding capacity, transpiration rate, chlorophyll a and b, carotenoid content, and net photosynthetic productivity were examined. Finally, the stress tolerance of the varieties and lines was calculated, and the obtained results were supported by statistical and correlation analyses. The analysis of these variables, using methods such as correlation tests, descriptive statistics, and correlation methodologies, demonstrated significant differences in performance characteristics, including stress pressure, temperature, changes in water status, and nutrient availability, through comparison of experimental results using validated statistical analyses and techniques. According to the experimental results, Sultan-R1, C-278, Omad, Afsona, and Ridge-2 exhibited moderate to high physiological stability and adaptability. The results confirm that water exchange stability is a key physiological determinant of cotton tolerance to extreme environmental conditions.

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