Genetic Diversity Analysis And Salt Tolerance Evaluation Of Miscanthus Lutarioriparius Germplasm Resources

China has large area of saline-alkali soil,and how to maximize the utilization has been the focus issue in the scientists in China.According to the principle of not competing the land with grain,and using marginal soil to grow non-flood crop can maximize the utilization rate of saline-alkali soil resources,its biomass can also be used in bio-energy,bio-economy,ecology,food and ornamental fields.However,the cultivation of M.lutarioriparius on saline-alkali land was greatly restricted by lake of salt tolerance germplasm in M.lutarioriparius.Therefore,selection of salt-tolerant germplasm and exploration of the genetic diversity in M.lutarioriparius have important theoretical value for guiding the breeder to breeding the new salt-tolerant M.lutarioriparius cultivars and exploring the mechanism of salt-tolerant in M.lutarioriparius.The purpose of this study is to determine the optimal screening salt stress concentration and investigation of salt stress index in M.lutarioriparius,and select a certain amount of M.lutarioriparius germplasm to obtain the germplasm with different salinity tolerance,establish the evaluation method of salinity tolerance in M.lutarioriparius,and then analyze the genetic diversity of M.lutarioriparius salinity tolerance to study the relationship between salinity tolerance and germplasm diversity.The main conclusions of this study are as below:(1)Using 21 SSR primers to apply to 25 M.lutarioriparius germplasm genetic diversity analysis,total amplification bands,236 polymorphism with 195,the total percentage of polymorphic loci was 81.56%,total amplification of 37.54 alleles and 27.82 effective alleles,allele number variation is 1.28 ～ 2.0,the average SSR loci is 1.79,an effective number of alleles variation average loci was 0.20 ～ 1.73,with average is 1.32;Shannon information index(I)ranges from 0.06 to 0.40,with an average of 0.24.The variation of Shannon-Weaver diversity was 0.10～1.29,and the average was 0.41.This study showed that the polymorphism of the 21 pairs of SSR primers selected was very high,which could well identify the subjects’ materials and analyze the genetic diversity.It can also be seen from the changes of these genetic diversity indicators that the 25 genotypes of M.lutarioriparius germplasm have rich genetic diversity.(2)The germplasm was grouped into 4 clusters by UPGMA,and it was found that the classification of the groups had little relationship with the regional origin of the species.(3)Using salt pond system,four genotypes were grown under different treatments of salinity(0 m M,100 m M,200 m M,and 300 m M Na Cl),the morphological and physiological indexes were measured,and the data analysis was carried out by variation.It was found that the dispersion degree of each material was the largest after 7 days of treatment with 100 m M Na Cl salt concentration,which could well show the difference of salt tolerance between each material.(4)25 M.lutarioriparius were treated with 100 m M Na Cl and measured the traits of 7days later.Based on the principal component analysis and fuzzy membership function,the salt tolerance of 25 materials was divided into 4 categories.The first categories(two highly salt-tolerant strains,accounting for 8% of the test materials): A0106、B0149.The second categories(three moderately salt-tolerant strains,accounting for 12% of the test materials): C0111、B0431L、B0129.The third categories(8 low-grade salt tolerance strains,accounting for 32% of the test materials): B0426R、C0121、B0143、C0133、C0104、B0132、C0142、A0112.The fourth categories(there were 12 salt-sensitive strains,accounting for 48% of the test materials): B0120、B0121、A0118、C0118、B0119、C0112、A0108、A0105、A0101、C0132、C0149、B0427L.(5)The results of SSR =analysis showed that the distribution of the materials with the same salt tolerance was consistent,but they could not reach a significant correlation.This may be due to the low correlation between these markers and salt tolerance genes,or to the fact that plant sanity tolerance is determined by a large number of mutated,polygene-controlled quantitative traits,with different genes that determine salt tolerance and gene expression.