| In this paper,60 alfalfa materials were selected as the research objects,and their salt tolerance evaluation at seedling stage and genetic diversity analysis of different salt tolerant varieties of alfalfa were carried out,aiming to provide a theoretical basis for the breeding and Germplasm development of alfalfa varieties.The main results are as follows:(1)salt tolerance evaluation of Alfalfa at Seedling Stage:5 salt tolerant and 5 salt sensitive varieties were screened by phenotypic identification with 60 alfalfa varieties at home and abroad.The content of chlorophyll,superoxide dismutase(SOD),catalase(CAT),peroxidase(POD)activity and malondialdehyde(MDA)of the preliminarily screened varieties were screened by IBM SPSS Statistics 19 software.The relative inhibition rate of root length and plant height was analyzed by principal component analysis,subordinate function and system cluster analysis.According to the comprehensive evaluation value(D value),the salt tolerance was ordered.The results showed that under the stress of 100 mmol L-1 NaCl,Peru>Asi>CaoyuanNo.3>Xingping>Domestic alfalfa;under 250 mmol L-1 NaCl stress,Juneng>Adina>JunengNo.7>QishiT>Kanghanl5.Cluster analysis of D value shows that 5 samples of salt sensitive materials can be divided into 3 categories:Peru,Asi and CaoyuanNo.3,which belong to strong salt tolerance;Xingping is a class of moderate salt tolerance;domestic alfalfa is a class of weak salt tolerance,and 5 salt tolerant materials can be divided into 3 categories:Kanghan15 and QishiT are one and weak.Salt tolerance;Adina and Juneng salt tolerance;and the JunengNo.7 is a kind of moderate salt tolerance.(2)genetic diversity analysis of Alfalfa with different salt tolerant varieties:①The results of genetic diversity of 5 alfalfa and 5 alfalfa materials with SSR molecular markers showed that 9 microsatellite primers were obtained from 42 pairs of microsatellite primers and 9 microsatellite primers were polymorphic and with 9 microsatellite primers in 110 single alfalfa varieties of 10 Alfalfa varieties.738 loci were detected,including 331 monomorphic loci,407 polymorphic loci and 55.149%total polymorphic loci;the ratio of the effective allele and allele was 0.521,the average heterozygosity was 0.799,the average Shannon index was 1.886,the average polymorphism was 0.799,and IBM SPSS Statistics was used.19 the average percentage of polymorphic loci,the average heterozygosity,the average PNe/Ao,the average Shannon index and the average polymorphism of the 10 Alfalfa varieties were evaluated comprehensively.According to the comprehensive evaluation value(D),the degree of genetic variation in the 10 Alfalfa varieties was ranked:Juneng>QishiT>JunengNo.7>Asi>Xingping>Adina>Peru>Kanghanl5>CaoyuanNo.3>Domestic alfalfa,indicating that these 10 Alfalfa materials have high genetic diversity.②The genetic differentiation coefficient(Gst)between the materials was 0.100 indicating that most of the genetic variations of the 10 Alfalfa materials occurred within the various varieties.③Neighbor-Joining Nei genetic distance using MEGA6.0 software(NJ),Minimnm Evolution(ME),UPGMA clustering analysis showed that 5 copies of the salt sensitive materials always clustered together,indicating closer relationships between these 5 materials;and 7 giant giant together as a class that is close to their kin;15 in the NJ and ME analysis of drought resistance in the cluster always relatively large genetic distance and opposition than other relationships between materials;in ADINA in ME cluster analysis and T Knight clustered in UPGMA and ADINA in cluster analysis and drought resistance in 15 and together as a class.15 and that ADINA and drought Knight T had closer relationship. |
