Study On Genetic Diversity Of Agropyron Gaertn Germplasm Resources

In this study,40 materials of Agropyron Gaertn including 5 species were used analyzing, identification and evaluation.Seventeen morphological characters were studied using anova analysis,correlation analysis,principal component analysis and cluster analysis.Meanwhile, genetic diversity was assessed among 33 materials by ISSR.The mian results as fllows:1.The result of phenotype diversity shows that the Agropyron Gaertn plants rich in morphological variation,the average coefficient of variation is 22.94%and the biggest variation is the rachis internode length.The anova analysis showed that:all materials between species and intraspecies both reached the extremely obvious difference or significantly difference.This findings indicated the abundant morphology diversity.Principal component analysis revealed that the first five principal components account for 76.39%of the total variation.Based on the morphological data,all materials were clustered into three groups at genetic distance of 15.The first group mainly was A.cristatum which came from foreign;The second group is mostly A.desertorum and the third is mainly of national A.cristatum.The cluster result is obviously divided by species,but there were crosses in the species.The findings also implied a strong correlation among the germplasm materials and geographical environment.2.Suitable reaction systems and programs of the ISSR analysis for Agropyron Gaertn were designed.The following was the 20μL reaction system with 40 ng genomic DNA,0.2mmol/L dNTP,0.5μmol/L ISSR primer,1U Taq DNA Polymerase,2μL 10×PCR Buffer,2.5mmol/L MgCl₂.Amplificative thermal reaction program suitable for the ISSR-PCR analysis in the Agropyron Gaertn was devised as followings:one preliminary denaturation at 94%for 4min;11 cycles each involved at 94℃for 30s,anneal at 60℃(60°C-58℃) for 45s,with 1℃declined each cycle,extended at 72℃for 1min 45s;then followed by 24 cycles each with denaturation at 94℃for 30s,anneal at 50℃(50℃-48℃) for 45s,extended at 72℃for 1min 45s;and a final extension at 72℃for 5min.then holding the temperature at 25℃,and keeping final products at 4℃.3.The 11 ISSR primers screened from 93 ISSR primers were utilized for the amplification reaction of Agropyron G.template DNA by PCR reaction.The result showed that:A total of 84 bands were obtained by amplification of the polymorphic primers of 33 cuttings,among which 59 bands were found to be polymorphic.The percentage of polymorphic bands was 70.02%.The result revealed that there was rich genetic diversity with the Agropyron G The Nei's genetic similarity coefficient of the germplasm materials ranged from 0.083 to 0.706,and the average Nei's coefficient was 0.395.The dendrogram was obtained by the UPGMA clustering method.The thirty- three materials of Agropyron G.were clustered intofour groups at the GS(0.52).The materials from the same origin were frequently clustered into one group.The findings implied a strong correlationwith the germplasm resources,geographical and ecological environment.4.It was found that different markers reflected different degrees od genetic difference and diversity level,ISSR marker using genome DNA showed the most greatest diversity among populations.The materials from the same origin were frequently clustered into one group.The findings implied a strong correlationwith the germplasm resources,geographical and ecological environment.