Drought Tolerance Identification and Eevluation of Maize during Flowering Stage in Guangxi

Total 20 maize varieties were subjected to drought stress at flowering stage, and then the relative water content, soluble sugar content, chlorophyll content, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in their leaves, as well as their yields were determined. The drought tolerance of the physiological and biochemical indexes was scored by five-level scoring method, and the drought tolerance index was calculated by the yield index to comprehensively evaluate the drought tolerance of maize during flowering stage. The results showed that the scores of drought tolerance of the maize varieties ranged from 1.929 3 to 5.659 5. Among them, the scores of Zhengda 619, Guidan 162 and Guidan 0810 were greater than 5.0, followed by Dika 008, Xianyu 30T60, Xianzhengda 901, Qingnong 68, South America No.1 and Wanchuan 1306 of which the scores were in the range of 4.0-5.0. The drought tolerance indexes were in the range of 0.410 4-1.096 3. Among the test maize varieties, the drought tolerance indexes of Guidan 0810, Pacific 99 and Zhengda 619 were greater than 1.0, and those of Xianyu 30T60, Dika 008 and South America No.1 were in the range of 0.9-1.0. The correlation between the two kinds of evaluation results was 0.588 7 and was extremely significant. The five-level scoring method and the drought tolerance index can be used simultaneously for the evaluation of drought tolerance of maize during flowering stage. The two aspects of evaluation results showed that Guidan 0810, Zhengda 619, Xianyu 30T60, Dika 008 and South America No.1 were drought-tolerant varieties, among which Guidan 0810 and Zhengda 619 were extremely highly drought-tolerant varieties.