Comprehensive Assessment And Physiology Character Of Different Wheat Genotypes Under Drought Stress

Drought is one of the most important adversity factors restricting agricultural production, which creates food substantially reduction of output. Water shortage has become the main factors limiting stable and high yield of wheat. With 8 varieties of wheat, we studied the changes of the root length relative growth rates, relative growth rate of root surface area and root diameter under drought conditions, and made the cluster analysis on 8 different wheat varieties based on these three indicators. During the whole growth stage, we measured 16 agronomical traits, physiological and biochemical indexes, photosynthetic traits in 8 different wheat varieties, the differences of drought resistance in 8 wheat varieties were analyzed. On this basis, 4 suitable principal components for identifying drought resistance were found, the main results are as follows:1. In the seedling stage, 8 different wheat varieties were processed by drought treatments(200 g/L PEG-6000), the growth of root system was recorded. We found that the root length relative growth rates and relative growth rate of root surface area of Zhoumai 22, Huayu 198, Zhoumai 16, Bainong 207, Luohan 7, Bainong AK58 and Bainong 64 are positive number, These indicated that the root growth was inhibited under drought stress; But Zhoumai 18 was adverse, maybe it related with the characteristics of Zhoumai 18; The growth rate of root diameter in 8 different wheat varieties were negative, these showed that the growth of wheat root diameter was promoted under drought stress. 8 wheat varieties were divided into four categories using cluster analysis method: the first category includes Bainong AK58 and Bainong 64; the second category includes Bainong 207, Luohan 7 and Zhoumai 16; the third category includes Huayu 198 and Zhoumai 22; the fourth category includes Zhoumai 18.2. The agronomical traits of 8 wheat cultivars were determined under drought stress and control condition, the results showed as follows: the value of agronomic characters of 8 wheat varieties was decreased under drought stress, but the decline range was different, the value of yield character was declined the most obviously, and the value of plant height character was decreased slightly. According to the drought resistance index of different varieties, the results showed that drought resistance index of Bainong AK58, Zhoumai 22 and Bainong 207 were higher, they were 0.96, 0.94 and 0.90, respectively.3. Flag leaves of 8 different wheat varieties under drought stress and control condition were collected, SOD, POD, CAT and soluble protein content of 8 different varieties were determinated, the results showed as follows: the activity of SOD, POD, CAT were decreased under drought stress, the SOD activity of Huayu 198 was decreased the most obviously under drought stress, Bainong 207 and Bainong AK58 decreased slightly; POD activity of the 8 varieties was fallen, but no significant declined. The CAT activity of Huayu 198 decreased the most obviously, and Luohan 7 decreased slightly; The soluble protein content of 8 different varieties under drought stress was also fallen, Luohan 7 decreased slightly, and Huayu 198 decreased the most obviously, The soluble protein content of Bainong AK58 and Bainong 207 was higher under drought stress.4. The fluorescence parameters of wheat flag leaves were determined by chlorophyll fluorescence spectrometer, the results showed as follows: Fo was increased under drought stress, Huayu 198 were increased larger, which photosynthetic reaction-center was obviously damaged, the increase amplitude of Luohan 7 is smaller, which photosynthetic reaction-center was slightly damaged. The Fm of 8 wheat varieties was decreased under drought stress, but the decline range was different. Zhoumai 18 and Bainong AK58 were slightly decreased, and Huayu 198 decreased obviously. Fv/Fo and Fv/Fm of 8 different wheat varieties were both decreased under drought stress, and Huayu 198, Zhoumai 22 and Luohan 7 were decreased larger, it showed that the photosynthetic efficiency was inhibited under drought stress.5. Principal component analysis was carried on 16 traits of 8 wheat varieties, such as plant height, spike length, flag leaf length, flag leaf width. We got four principal component indexes, including thousand kernel weight, ears permu, CAT, flag leaf length.