Comprehensive evaluation of physiological and biochemical characteristics and drought resistance of maize varieties during the germination stage in Guangxi

【Objective】Physiological and biochemical indices were used to evaluate the drought resistance of maize varieties in the Guangxi region during the germination stage,so as to provide a reference for the selection and cultivation of drought resistant maize varieties in Guangxi.【Method】Using 20% PEG-6000 solution to simulate drought stress,the drought resistance test was carried out on 14 maize varieties in Guangxi during the germination stage. The contents of chlorophyll,soluble sugar and malondialdehyde(MDA),and the activities of superoxide dismutase(SOD),peroxidase (POD)and catalase(CAT)of each maize variety's germ under control conditions(distilled water)and drought stress were measured to explore the effect of drought stress on maize germination characteristics. The evaluation of the drought resistance of the different maize varieties used the membership function method.【Result】Compared with the control,the growth and development of all tested maize varieties were significantly inhibited under drought stress,showing difficult seed germination and slow embryo growth,but different varieties were affected differently. The differences of each physiological and biochemical index among varieties and treatments reached extremely significant levels(P<0.01). Compared with the control,the contents of chlorophyll and soluble sugar,the activities of SOD,POD and CAT were decreased, while the MDA content increased under drought stress. In the evaluation of the membership function method,the largest index weight coefficient was the MDA content,reaching 46.96%,followed by SOD activity,reaching 21.77%. The D value of varieties membership function method were between 0.176 and 0.795,among which the D value of Zhaoyu 215 and Guidan 162 were greater than 0.7,belonging to the strongly drought resistant varieties;the D value of Guidan 6205, Guidan 666 and Zhaoyu 200 were between 0.5 and 0.7,belonging to drought resistant varieties;the D value of Guidan 660,Guidan 658,Guidan 673,Guidan 6209,Guidan 203 and Guidan 6203 were between 0.4 and 0.5,belonging to middle drought resistant varieties;and the D value of Guidan 669,Guidan 671 and Guidan 668 were less than 0.4,belonging to weakly drought resistant varieties.【Conclusion】The contents of chlorophyll,soluble sugar,MDA,and the activities of SOD,POD and CAT could be used as drought resistance evaluation indices during the maize germination stage,among which MDA content and SOD activity provide the strongest evaluation indices. Zhaoyu 215,Guidan 162,Guidan 6205, Guidan 666 and Zhaoyu 200 showed the strongest drought resistance of the 14 maize varieties tested.