Genetic diversity and construction of primary core germplasm in Cornus officinalis by ISSR marker.

The genetic diversity of 48 germplasm resources of Cornus officinalis in Zhejiang,Henan and Shaanxi Province were analyzed by ISSR technique,and the primary core germplasm were constructed with progressive sampling method of smallest genetic distance.13 primers,which showed good repetitive,special bands and distinct polymorphism,were selected from 51 random ISSR primers.Then the total 190 loci were amplified by these selected 13 primers,including 93.16% polymorphic loci.The results indicated that the average of Shannon information index(I),Nei's genetic diversity(H) and effective number of alleles(NE) by POPGENE32 analysis were 0.402 5,0.259 4 and 1.425 0,respectively.The result of analysis by NTSYS-PC software showed there was upper coherence between the clustering result and source core germplasm collection.The result showed the index change of germplasm genetic diversity was less than that before sampling.Although the Shannon's information index and Nei's genetic diversity were increased a little,the percentage of polymorphic loci was obviously reduced.The bank of core germplasm from No.3 sampling was most representative,whose sampling number was about 30% of the initial sampling,and the percentage of polymorphic loci was 96.0% before sampling.