| This study used respectively using SSR markers and of a mark from different countries about 49 a puffin tares germplasm resources research,explore the genetic diversity between puffins barnyard grass,from the molecular level of 49 puffin barnyard grass level of diversity and genetic relationship between germplasm resources and population structure analysis and evaluation,in order to later puffins tares germplasm resources protection,which lays an experimental basis for new varieties breeding and cultivar identification.(1)The total length of 154,428 unigene sequences of seashore paspalum was 160.05mb.SSR search was conducted and 33,817 SSRs sites were detected.There were 25,915 sequences containing SSR sites,accounting for 16.8%of the total number of sequences examined,with an average density of 4.73kb.The SSR repeat elements of paspalum are dominated by the SSR repeat type of trinucleotide(42.14%)and the SSR repeat type of single nucleotide(39.18%).Among the single-nucleotide repeats,the element A/T is the dominant one,accounting for 36.5%of the total SSR.Among the trinucleotide repeats,CCG/GGC is the most common one,accounting for 18.23%of the total SSR.Among the seashore paspalum SSR repeats,the number of repeats is 5-24 times,with only 10.22%over 12 times.(2)24 pairs of SSR primers were selected to analyze the genetic diversity of 49 pieces of seagrass resources.The range of Nei was 1.36～1.98,with an average value of 1.60,and the range of He was 0.25～0.46,with an average value of 036.1 ranged from 0.33 to 0.65,with an average of 0.53.According to UPGMA clustering analysis,the tested materials could be divided into three categories,and their fitting co-correlation coefficient R=0.688,indicating that the clustering results were reliable,and the clustering.results could well reflect the genetic relationship among paspalum germplasm resources.According to principal component analysis,the contribution rate of the first principal component is 45.54%,that of the second principal component is 11.73%,and that of the third principal component is 5.65%.The cumulative contribution rate of the three principal components is 62.92%.The results of principal component analysis are basically consistent with the clustering results.(3)20 pairs of SRAP primers were selected for the amplification of 49 pieces of seperum germplasm resources.The range of He was 0.36～0.49,with an average of 0.45;the range of I was 0.55～0.60,with an average of 0.64;and the range of Nei was 1.59～1.97,with an average of 1.83.The difference of SRAP polymorphism among seperum germplasm resources was significant.According to UPGMA clustering analysis,the tested materials could be divided into four categories,and their fitting co-correlation coefficient R=0.669,indicating that the clustering results were true and reliable,and the clustering method accurately reflected the genetic relationship between paspalum germplasm.According to the principal component analysis,the contribution rate of the first principal component is 16.63%,the contribution rate of the second principal component is 9.06%,the contribution rate of the third principal component is 5.70%,and the cumulative contribution rate of the three principal components is 31.39%.The clustering results of pca are only partially consistent with those obtained by UPGMA,which may be because different clustering methods reflect different information of materials.(4)In order to understand the correlation between SSR and SRAP markers,the correlation analysis of 49 pieces of seperum germplasm resources based on the genetic similarity coefficient matrix of the two markers was conducted,and it was found that there was an extremely significant positive correlation between the two markers(R=0.686).The data of the two molecular markers were integrated and analyzed,and the results were found to be basically consistent with the results of the self-clustering of each marker.This result once again proved the high similarity of the results of the two molecular markers,and demonstrated the applicability of the two molecular markers in the study of genetic diversity of paspalum.Therefore,the comprehensive analysis of multiple molecular marker data is more suitable for the detection of genetic diversity and the analysis of genetic relationship of paspalum.(5)Structure2.3.4 software was used to analyze the SSR markers and SRAP markers of 49 pieces of paspalum millet materials,both of which had the maximum similarity value in each group at K=2,indicating that the genetic structure analysis results of the population divided 49 pieces of paspalum into two groups.By comparing the two types of tags divided by Structure2.3.4 software,it is found that the two types of tags are basically the same.In conclusion,SSR and SRAP markers were found to be of high similarity in the study of genetic similarity of paspalum,and both of the two molecular markers were suitable for genetic diversity detection,genetic relationship analysis and population structure analysis of paspalum... |
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