WATER-BALANCE MAINTENANCE AND SALINITY TOLERANCE OF COTTON GENOTYPES UNDER SALINITY STRESS
Keywords:
cotton, salinity stress, TWC, RWC, ELWL, physiological marker, breeding, toleranceAbstract
Salinization of irrigated lands remains one of the principal constraints to sustainable cotton production in Uzbekistan. Under conditions of water scarcity and increasing soil salinity, rapid and reliable identification of salt-tolerant genotypes using physiological markers is a priority for breeding programs. This study evaluated the physiological responses of cotton (Gossypium hirsutum L.) genotypes to salinity using TWC, RWC, and ELWL indicators and identified promising tolerant donors for breeding. Seventeen promising genotypes were tested under moderate and high salinity in a randomized block design with 3–4 replications. Measurements included total water content (TWC, %), relative water content (RWC, %), and excised-leaf water loss (ELWL, %; 3-h protocol). Data were analyzed by two-way ANOVA (factors: Genotype, Salinity, and Genotype×Salinity interaction). Increasing salinity generally decreased TWC and RWC and increased ELWL (p < 0.001). ANOVA confirmed significant effects of Genotype, Salinity level, and their interaction on all traits (p < 0.001). The tolerant group comprised Yulduz-2, T-1002, T-1003, and T-1090, which maintained relatively higher TWC/RWC and lower ELWL even under strong salinity. Ishonch, L-217, L-218, Orzu, and T-1050 were identified as sensitive (sharp declines in TWC/RWC with elevated ELWL). A combined approach based on TWC, RWC, and ELWL provides an effective suite of physiological markers for rapid and reliable assessment of salinity tolerance. The tolerant genotypes Yulduz-2, T-1002, T-1003, and T-1090 are recommended as donors of salinity tolerance for breeding programs.
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