Screening And Identification Of Salt-tolerant Rice Germplasm Resources At Seedling Stage

Soil salinization has long become a global environmental problem that needs to be solved urgently.Improving soil structure and physical and chemical properties is one of the ways to solve soil salinization.As one of the important food crops,rice is a moderately salt-sensitive crop.Therefore,it is of great significance to select rice varieties with strong salt tolerance from rice germplasm resources.In this study,126 core germplasm populations were used as the research materials,and the salt stress conditions of 100mmol/L Na Cl solution were selected to conduct preliminary screening and identification of the salt tolerance of this population at the seedling stage.Measure the plant height,Chlorophyll content(SPAD),fresh/dry weight of above ground,fresh/dry weight of ground,K~+,Na~+content of ground,K~+,Na~+content of ground,rate of dead leaves,rate of dead seedlings,root system under salt stress The total root length,total surface area,total volume and other trait indicators are comprehensively evaluated and analyzed for its salt tolerance.(1)After 4 days of salt treatment,most of the rice plants were inhibited to varying degrees,such as plant height,SPAD,aboveground fresh/dry weight,underground fresh/dry weight,aboveground K~+,Na~+content,underground K~+There are significant differences among traits such as,Na~+content,total root length,total root surface area,and total root volume.Among them,seedling plant height,SPAD,aboveground fresh/dry weight,underground fresh/dry weight,root system The total root length,total surface area and total volume were significantly lower than those of the control group.The Na~+content in the underground was significantly higher than that in the control group under salt stress,and it was higher than the accumulation of K~+in the underground.The accumulation of Na~+in the shoots is lower than the accumulation of K~+.The Na~+/K~+in the underground is significantly higher than that in the above ground.(2)This study conducted principal component analysis on 17 rice seedling-stage salt tolerance related indicators,and selected 6 principal components to summarize the 17 related indicators,and based on the absolute value of the correlation coefficient of each factor in the 6principal components.And according to the absolute value of the correlation coefficient of each factor in the six principal components,four related indexes,namely,the relative fresh weight of the above ground,the relative fresh weight of the underground,the relative dry weight of the underground,and the rate of dead leaves as indicators for screening and identification.(3)By calculating the membership function and comprehensive evaluation D value of126 rice germplasm resources,the salt tolerance grade was evaluated according to the comprehensive evaluation D value,and 5 strong salt-tolerant materials and 29 sensitive materials were selected.Salt materials,and 92 parts of moderately salt-tolerant materials.(4)By comparing the salt tolerance of different types of rice,it is found that the salt tolerance of the typical japonica rice and the partial japonica rice is stronger than that of the classic indica and partial indica rice.