Genetic Diversity And Screening Of Miscanthus Spp.Germplasms For Salt-tolerance From East Floristic China Region

Miscanthus is a biomass material with great development potential.It is widely distributed in all parts of China.The East China region is the main overlapping area of four species of Miscanthus(M.sinensis,M.floridulus,M.sacchariflorus,M.lutarioriparius)with development potential.As the most important ecological industrial plant,Miscanthus can provide a theoretical basis for domestication of wild resources and breeding of new varieties by studying the genetic diversity of its germplasm resources.In this study,we selected 36 samples of Miscanthus spp.include four species from East China region,which were used to study the genetic diversity of the phenotypic characters of Miscanthus spp.during their overlapping region.Their plant height,inflorescence length,basal diameter,tiller number,maximum leaf length,maximum leaf width,ratio of leaf length to width,dry matter yield were determined by using plant phenotypic genetic diversity,Simple Sequence Repeats,the photosynthetic physiological response.The results showed:(1)The interspecific differences trend in selected phenotypic of Miscanthus spp.was as follows: tiller number> basal diameter> dry matter yield> inflorescence length>plant height> maximum leaf length>maximum leaf width>ratio of leaf length to width.There were significant interaction effects of eight phenotypic traits among and within species.The variation coefficient of all eight phenotypic traits was ranged from 7.94% to76.80%,and the Shannon's index of all eight phenotypic traits was ranged from 1.27 to 1.78.(2)The overall plant height of Miscanthus spp.from East China region had significant negative correlations with latitude and altitude,and the overall dry matter yield was significant negative correlation with latitude.(3)The SSR primers of maize and sugarcane were used to demonstrate the versatility of SSR primers.Therefore,SSR molecular markers can be used to study the genetic evolution relationship between Miscanthus spp..(4)Based on the cluster analysis of phenotypic traits,the 36 Miscanthus germplasms could be clustered into three groups,which the first group containing all M.sacchariflorus species,the second group containing all M.sinensis and M.floridulus species,and the last group was all M.lutarioriparius species.Based on the analysis of genetic distance,the 36 Miscanthus germplasms could be clustered into two groups,which the first group containing all M.lutarioriparius species and most M.sacchariflorus species,the second group containing all M.floridulus species and most M.sinensis species.(5)Based on this research,we selected 12 samples of Miscanthus spp.include four species(M.sinensis,M.floridulus,M.sacchariflorus,M.lutarioriparius each with 3 samples).All the tested samples were treated with 0,0.2%,0.6%,1% NaCl for a week in the laboratory.the photosynthetic physiological response parameters(chlorophyll content,net photosynthetic rate,stomatal conductance),biofilm stability-related physiological responses(malondialdehyde content),osmotic adjustment-related physiological responses(proline content),and ROS clearance-related physiological response indicators(superoxide dismutase activity)of different tested samples under different concentration NaCl were measured.Concern to the results of comprehensive evaluation of the physiological response,the order of salt resistance of each tested samples is: the Miscanthus lutarioriparius were more resistant to salt.However,the salt-resistance ability of Miscanthus sacchariflorus is weaker than that of most of Miscanthus sinensis and Miscanthus floridulus.