Genetic Diversity and Structure of 255 Cultivars of Ziziphus jujuba Mill
[Objective] There are abundant jujube germplasm resources in China.A total of 255 cultivars of Ziziphus jujuba Mill.from 22 provenances were used as materials to reveal their genetic diversity and phylogenetic relationship by SSR analysis,and the results of analysis would help us to manage jujube germplasm resources and offer references for molecular maker-assisted breeding.[Method] Good genomic DNA was extracted from young leaves of jujube germplasm resources following the improved CTAB method,and then were amplified by simple sequence repeat molecular markers to analyze genetic diversity and genetic structure with the selected high-efficiency primer pairs which were excavated based on the genome sequencing.Separation of the amplified fragments was performed on 8％ denaturing polyacrylamide gels and the gels were stained with AgNO3 for visualizing the SSR fragments.The data were counted by presence or absence of the band and the percentage of polymorphic loci (PIC) was calculated.UPGMA cluster analysis was carried by software NTSYS,the optimal number of groups and population genetic structure was analyzed by software Structure.[Result] Totally,117 polymorphic alleles were revealed with 23 primer pairs which was selected from 64 primer pairs,each primer amplified polymorphic loci ranged from 2 to 10,with an average of 5.09 for each primer pairs.Polymorphism information content (PIC) values for the primer pairs ranged from 0.359 to 0.727,with an average of 0.548,these polymorphisms primers could be further applied to other study.The fingerprint for some jujube cultivars was established with 1-2 markers,providing a reference for the management of jujube germplasm.Meanwhile,based on the UPGMA cluster analysis,255 cultivars were divided into fifteen subgroups,which included four big groups and eleven small groups.Similarity coefficients among the cultivars were between 0.71 to 1.00,‘Beijinghuashengzao' was clustered into one separate group,which has a distant relationship with other cultivars.The similarity coefficients of ‘Fengjiejidanzao' and ‘Xupujidanzao',‘Shannxinaizao' and ‘Tianjindamayazao' were both 1.00.In some subgroups the genetic relationship between cultivars and their provenances has a significant positive correlation,but the cultivars and their uses has no significant correlation.Based on K and ΔK values,255 jujube cultivars were also divided into fifteen populations by the population genetic structure analysis.The kinship among cultivars in the same population was relatively simple,and a few cultivars contained genetic component of other groups.The cultivars from Shanxi or Shannxi were distributed in most populations,indicating jujube cultivars of the two provinces played important roles in the gene exchange among populations.The jujube cultivars from Hunan of the South region formed a relatively alone population,indicating that the cultivars might be from the same source,or in the long-term cultivation few times of gene exchange were happened in Hunan cultivars with other populations.Different geographical environment played a key role in the evolution of jujube germplasm populations,some cultivars were selected from the same geographical environment and the others were selected by genetic recombination among those cultivars from the various geographical environment.Meanwhile,the consistency of the two different methods was further verifed the accuracy of the results,which provide useful clues and reference for the genetic diversity and structure of jujube germplasm.[Conclusion] Geographical environment play significant roles in the population evolution of jujube cultivars,affecting the genetic structure composition between different habitats.
国家科技期刊平台
NSTL
万方数据
维普
