Saline-alkali Resistance Identification And Evaluation Of Rice Germplasm Induced By High Energy Heavy Ion Beam

In order to investigate the difference of salt-alkali tolerance of rice varieties at different growth stages.In this study,89 mutant materials from rice variety "Tonghe899" were selected,which were induced by high-energy heavy ion beam irradiation.The salt and alkali resistance during germination period was identified.Using germination rate as the index,10 typical mutant materials were screened for the identification and evaluation of salt and alkali tolerance at seedling and whole growth stage.A variety of analysis methods were used to comprehensively evaluate the saline-alkali tolerance of rice at seedling stage and whole growth stage.The evaluation indexes that could be used for the identification of saline-alkali tolerance of rice at germination stage,seedling stage and whole growth stage were screened.The relationship among the indexes was analyzed to explore the relationship between saline-alkali tolerance of rice at germination stage,seedling stage and whole growth stage.The results showed that:1.Saline-alkali stress significantly affected the germination rate of rice seeds;Under the control condition,the germination rate of rice seeds remained above 96%,and under the saline-alkali stress,the germination rate of rice seeds ranged from9.33% to 88.67%,with significant differences among varieties.According to the relative saline-alkali damage of germination rate,91 samples were divided into 5groups.The resistance of 6 materials reached grade 1,24 materials reached grade 3,30 materials reached grade 5,26 materials reached grade 7,and 5 materials reached grade 9.2.Saline-alkali stress significantly affected rice seedling growth,biomass and ion content in plants.The comprehensive evaluation of rice was carried out by using fuzzy function method,and the results of comprehensive evaluation and single index evaluation were compared by linear analysis.The survival rate,seedling fresh weight,root fresh weight,seedling dry weight,root dry weight and K+/Na+ in roots could be selected as indexes for the identification of salt-alkali tolerance of rice at seedling stage.3.Saline-alkali stress significantly affected the agronomic traits and ion content in rice plants during the whole growth period.The fuzzy function method was used to evaluate rice comprehensively,and the linear analysis was used to compare the results of comprehensive evaluation and single index evaluation.The K+/Na+ ratio at heading stage,yield,number of tillers,panicle weight,1000-grain weight and K+/Na+ at maturity stage were selected as indexes for the identification of salt-alkali tolerance of rice during the whole growth period.4.Correlation analysis of salt-alkali tolerance indexes of rice in different growth stages found that: The germination rate at germination stage was significantly positively correlated with the survival rate,seedling fresh weight and root dry weight salt and alkali tolerance coefficient(P < 0.01),and was significantly positively correlated with the root K+/Na+ salt and alkali tolerance coefficient at seedling stage(P < 0.05).There was an extremely significant positive correlation between the salinity tolerance coefficient of seedling survival rate and the salinity tolerance coefficient of K+/Na+ at mature stage of the whole growth period(P < 0.01).There was an extremely significant positive correlation between the salinity tolerance coefficient of root and the salinity tolerance coefficient of K+/Na+ at heading stage of the whole growth period(P < 0.01).5.The linear analysis of the comprehensive saline-alkali tolerance of rice at different stages showed that the evaluation results at germination stage and seedling stage were in very significant agreement.There was no consistency between the evaluation results of germination stage and the whole growth stage.There was no consistency between the evaluation results at seedling stage and the whole growth stage.6.Three salt-tolerant strains "Dongdao 122","Dongdao 112" and "M7041" were identified through comprehensive evaluation of germination stage,seedling stage and growth stage.