Study On The Phylogentic Relationship Of Corylus Species And Genetic Diversity Of C.heterophylla Populations By SSR

7 species (variety) of Corylus about 43 accessions and 14 C. heterophylla Fisch populations were selected and investigated in this study. The phylogenetic relationship among 7 species of Corylus was explored and genetic diversity of C.heterophyllaa populations was evaluated using SSR markers. The obtained results and conclusions were as follows:(1) The SSR reaction system was established and optimized; 29 pairs of SSR loci of C.avellana L. were selected. A total number of 137 alleles were amplified using 17 SSR primers. The average value of observed allele was 8.0588; The average value of effective allele was 5.0259; The mean of Ho and He was 0.5773 and 0.7855, respectively; UPGMA cluster analysis based on Nei's genetic distance divided the 7 species (variety) into three main groups: C.heterophylla Fisch, C.avellana L. and C.kweichowensis Hu; C.feroxWall.var.thibetica (Batal.Franch), C.yunnanensis A.Camus and C.chinensis Franch; C. mandshurica Maxim.et Rupr. The genetic diversity of C. heterophylla Fisch and C.avellana L. were higher than others and they were phylogenetically closer.(2) The PCR products were directly seqnenced using Sanger method and DNA sequence analyzer (Beckman 2000). The result showed SSR has highly homology among Corylus, O.davidiana Decne and the primers of SSR could be used to analyze relatives.(3) The C.heterophylla Fisch could reproduce both sexually and vegetativly. According to the methods of samLpes investigation and SSR marker, the vegetative reproduction was main. It clusters. The clusters have three main forms: single cluster, individual clone and mulriple clusters. Seed reproduction was beneficial to it's high genetic diversity(Na=5.1250,Ne =2.4996,Ho=0.7148,He=0.5474). The appropriate sampling method should be designed on the basis of distribution on species level and the population size, the degree of the mass, cluster size and distance on population level.(4) 25 pairs of primers were chosen for the analysis of 14 wild C. heterophylla Fisch Populationss. 239 alleles was presented at 25 SSR loci.Observed number of alleles per locus ranged from 2 to 19 and average value of allele (Na) was 9.56; Effective number of alleles (Ne) was from 1.209 to 10.889, averagely 4.78; The expected total heterozygosity (He) ranged from 0.174 to 0.911 and mean was 0.729; The observed total heterozygosity (Ho) ranged from 0.191 to 0.921, mean was 0.552.(5) On the population level, Na =3.57, Ne=2.68, Ho =0.553, He=0.582. The genetic diversity of Henan province Hui county was most (Na=4.76,Ne=3.41,Ho=0.608,He=0.685) and Hebei province Kuancheng county's was the least(Na=1.44,Ne=1.44,Ho=0.44,He=0.251). A low level of genetic differentiation among populations was detected based on Nei's genetic diversity analysis (Fst=0.2485) and main variations was within population (75.15 %). A significantly high degree of genetic differentiation occurred among populations.(6) UPGMA cluster analysis based on Nei's genetic distance divided the 14 population into four main groups; Gene flow was low (0.756). Additionally, Nei's unbiased genetic distance matrix compared with a corresponding geographic distance matrix showed the two matrices were not significantly correlated (r =0.5144, P=0.9989).