Abstract:
Objective Aimed to investigate the response of cotton seeds to low temperature stress during germination and to comprehensively evaluate the cold tolerance of different varieties using multiple indicators.
Methods 18 cotton varieties were subjected to low-temperature stress. Germination potential, germination rate, germination index, hypocotyl length, main root length, above-ground and underground dry/fresh weight, and the physiological and biochemical characteristics were measured. Differences in germination-related indicators among varieties were analyzed, and cold resistance during the germination was comprehensively evaluated using fuzzy membership function method.
Results Based on indoor germination tests and physiological biochemical indices, the 18 cotton varieties were classified into four groups: Xinshixuan 122 and Xinshixuan 172 were identified as highly cold- tolerant during low-temperature germination; Xinluzhong 75, Guojian variety J206-5, Xinluzao 50, Xinluzhong 88, Zhongmian 127, and Zhuangjiahan 962 were classified as cold- tolerant; Xinluzao 61, Xinshixuan 132, Xinshi 518, and Xinluzao 73 were evaluated as low- cold-tolerant, Xinnongmian 1, Xinluzhong 33, Xinluzhong 82, Xinluzao 57, Xinshixuan 162, and Xinnongmian 2 were identified as cold-sensitive during germination under low temperature.
Conclusion Cold-tolerant cotton varieties adapt to low-temperature stress by enhancing antioxidant enzyme activities, accumulating osmoregulatory substances, and alleviating membrane lipid peroxidation. Among the tested genotypes, Xinshixuan 122 and Xinshixuan 172 demonstrated the most promising performance, suggesting their potential as valuable germplasm resources for breeding cold-tolerant cotton cultivars.
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