Response Of Different Maize Varieties To Salt Stress And Screening Of Salt Tolerant Varieties

With the aggravation of soil salinization and the increase of saline-alkali land area year by year,the selection and cultivation of salt-tolerant maize varieties is becoming more and more urgent.In order to study the response law of different maize varieties under salt stress,the maize varieties with strong salt tolerance were screened out,so as to provide reference for adaptive cultivation and variety selection of maize in southern Xinjiang.In this experiment,41 maize varieties from different regions were selected as experimental materials.The response of growth and yield components of 41 maize varieties to salt stress was studied by combining indoor seed germination test,outdoor pot experiment and field identification test.The germination rate,germination potential,salt damage index,salt tolerance index,plant height,stem diameter,SPAD value,leaf area,biomass,MDA content,PRO content,SOD activity,POD activity and other indicators of 41 maize varieties were analyzed and identified.The response of different maize varieties to salt stress was revealed.The main results are as follows:1.Through the indoor seed germination test,it was found that salt stress could significantly inhibit the germination of maize seeds.The germination potential,germination rate,germ length,radicle length and salt tolerance index of maize decreased with the increase of salt concentration.The decrease of salt-tolerant varieties was lower than that of salt-sensitive varieties,and the salt damage index increased with the increase of salt concentration.The four indexes of salt tolerance index,germ length,radicle length and germination rate were determined as the main indexes of salt tolerance identification in maize germination stage.According to the comprehensive evaluation D value,the salt tolerance of 41 maize varieties at germination stage was evaluated,and 10 maize varieties with strong salt tolerance were obtained,which were Xianyu 335,Xianghe9918,Xuanhe 8,Xinyu 24,Nongfu 99,Hengyu 369,Xinyu 81,Jinnongyu 309,Jinfengjie 607 and Xinnong 008.2.Through outdoor pot experiments,it was found that salt stress significantly inhibited the growth of maize seedlings.The plant height,stem diameter,leaf area,SPAD value and biomass per plant of maize seedlings decreased significantly with the increase of salt concentration,and the effect on the underground part was greater than that on the aboveground part,resulting in an increase in root shoot ratio.The physiological and biochemical indexes of maize seedling leaves also changed significantly with the increase of salt concentration.The specific performance was that the cell membrane permeability increased,the activities of superoxide dismutase(SOD)and peroxidase(POD)increased significantly,and the contents of malondialdehyde(MDA)and proline(PRO)increased significantly,and the change range of salt-tolerant varieties was smaller than that of non-salt-tolerant varieties.180mmol/L Na Cl can be used as the suitable concentration for salt tolerance identification of maize at germination stage.According to the comprehensive evaluation D value,the salt tolerance of 41 maize varieties at seedling stage could be evaluated,and 10 maize varieties with strong salt tolerance were obtained,which were Pingan 1523,Zengyu157,Wofeng 9,Xinyu 66,Hongxing 990,Xinyu 24,Xinyu 81,Zhengdan 958,Qunce 888 and Xingnong 1.3.Through the field identification test,it was found that under the condition of saline-alkali soil,the plant height and stem diameter of the varieties with strong salt tolerance were also higher than those of the maize varieties with poor salt tolerance,and the leaf area and chlorophyll content were generally higher than those of the salt-tolerant varieties.Salt-tolerant varieties are higher than non-salt-tolerant varieties,indicating that the adaptability of salt-tolerant maize varieties to natural conditions is stronger than that of salt-tolerant varieties.Under the condition of saline-alkali land,the higher the plant height,the thicker the stem diameter,the more conducive to the accumulation of more dry matter,so as to achieve the purpose of increasing yield.The results showed that the grain number per spike,single ear weight,100-grain weight and yield of maize varieties with strong salt tolerance were higher than those of maize varieties with poor salt tolerance.There were significant differences among different salt-tolerant maize varieties,indicating that the varieties with strong salt tolerance had strong ability to regulate salt stress and were more suitable for cultivation in saline-alkali land.Combined with the conclusion of germination stage and seedling stage,seven maize varieties with strong salt tolerance were obtained,which were Xinyu 66,Xuanhe 8,Simon 208,Xinyu 81,Wugu 568,Zhengdan 958,and Yuanyuan 1.The results of this study can provide reference for the selection of salt-tolerant maize varieties in southern Xinjiang on the basis of broadening the salt-tolerant germplasm resources in southern Xinjiang.