| Blueberries are perennial woody plants belong to Ericaceae Vaccinium.It has extremely high nutritional value.In this study,DNA barcoding and phenotypic diversity were used to comprehensively analyze for blueberry germplasm resources.The aim is to explore genetic differentiation and genetic diversity among different cultivars.Eight DNA barcodes(rpoB,psbA-trnH,ycf5,rbcL,rpoC,matK,ITS and ITS2)of part of blueberry cultivars were amplified and sequenced.The amplification efficiency,sequencing success rate,genetic distance and barcoding gap were analyzed and using the Wilcoxon test to verify the calculation results of genetic distance.Finally,the cluster analysis of blueberry cultivars was performed by NJ tree method.The phenotypic character of blueberry cultivars were sorted out.Combining clustering analysis,correlation analysis,principal component analysis,Shannon-Wiener indexes and other analytical methods to study the genetic diversity of phenotypes.The summarized results were as follows:(1)In eight DNA barcodes,ITS and ycf5 had no amplification products in all blueberry samples.The amplification and sequencing rate of all five barcodes(rpoB,psbA-trnH,rbcL,rpoC and ITS2)were 100 %,except matK was 96.3 % and 99.04 %.the rates of amplification and sequexcing are relatively low.The mutation points of six barcodes were as follows: ITS2(11)>matK(4)>rbcL(3)>psbAtrnH(2)>rpoC(1)>rpoB(0).The genetic distances among or within blueberry cultivars were smaller,range is from 0.00016-0.00258.The genetic distances were greater among cultivars than within cultivars.(2)Barcoding gap analysis results showed that there was no obvious interval area was formed in all barcodes,but according to distribution,barcodes ITS2,psbA-trnH and matK tended to be distributed at both ends,especially ITS2.Wilcoxon test results showed that the interspecific variation of barcodes ITS2 and psbA-trnHwere more obvious than others,and greater intraspecific variation was found in psbA-trnH.The cluster analysis indicated that blueberry cultivars could be divided into two groups by psbA-trnH or rpoC,three groups by rbcL or matK,and four groups by ITS2.Furthermore,the identification rate of blueberry cultivars could be improved by the combination of barcodes and with the highest success rate is 20 % by ITS2+matK+rpoL+rbcL.(3)Principal component analysis showed that the first four principal component variance cumulative contribution rate was 53.477 %,and there were 25 traits with characteristic root value greater than 0.5,accounting for 67.57 % of the survey indicators,including tree type factors,leaf type factors,and fruit type factors,which can represent the phenotypic character of blueberry.The 15 qualitative traits were studied,including 55 variant types.The average variation types were 3.4 and the Shannon-Wiener index is between 0.32 and 1.36,with an average of 0.87.The 22 quantitative traits were relatively different in correlation,either positive or negative,the variable coefficient is between 4.77 % and 47.37 %.The fruit mass suggested the largest variation,the fruit form index the smallest variation,and the Shannon-Wiener index ranged from 0.22 to 2.06 with an average of 1.80.(4)According to the results of correlation analysis,principal component analysis and R-clustering analysis,37 test traits went through dimensionality reduction with 25 genetic information-rich traits selected,and Q-clustering analysis conducted.The results showed that when the euclidean distances Ll=17,all the cultivars were divided into five groups,and the cluster membership was found to be related with the cultivated habitat and cultivated groups. |
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