Genetic Diversity Of Germplasm Resources Of Toona Sinensis In Anhui Province Based On AFLP

Toona sinensis（A.Juss.）Roem belongs to the family Meliaceae and the genus Toona Roem.It is an important wood,medicinal,vegetable and landscaping tree species.The germplasm resources of T.sinensis in Anhui province are abundant,but the lack of basic information such as genetic diversity has caused problems for the protection and utilization of germplasm resources.The genetic diversity of germplasm resources of T.sinensis in Anhui province was investigated based on AFLP molecular markers using a total of 280samples from 14 populations.Results of the present research are as follows:1.The genetic diversity of germplasm resources of T.sinensis in Anhui province was investigated.The results revealed the relative low level of genetic diversity of T.sinensis in Anhui province,with the highest values for population Huoshan and the lowest value for population Shucheng.Three effective primer pairs were selected from 54 AFLP primer pairs（E-ACG/M-CAG?E-AAG/M-CAG?E-ATT/M-CAC）,and used for AFLP-PCR analysis.A total of 615 polymorphic loci were obtained for 14 populations.At the species level,the percentage of polymorphic loci PPL=100.00%,the number of effective alleles n_e=1.2008,Nei’s gene diversity H=0.1637,Shannon information index I=0.2993.At the population level,the percentage of polymorphic loci PPL_p=60.17%,the number of effective alleles n_ep=1.2014,Nei’s gene diversity H_p=0.1374,and the Shannon information index I_p=0.2278.2.The genetic structure of germplasm resources of T.sinensis in Anhui province was detected.The results indicated the relative low level of genetic differenciation between populations.The genetic variation mainly existed within populations,but there was no significant genetic difference between regions（north of Yangtze River,south Anhui and Dabie Mountains）.The genetic distances between populations ranged from 0.0048 to0.0169,with the highest value between populations Qianshan and population Shexian,the lowest value between populations Qingyang and population Shitai.The coefficient of genetic differentiation among populations(G_st=0.0921)exhibited the low level of genetic differences among populations of T.sinensis.Gene flow（N_m=4.9302）displayed frequent gene exchange among populations.UPGMA cluster analysis divided 14 populations into three groups,and the results obtained by principal coordinate analysis were consistent with the results of cluster analysis.Mantel test showed that the correlation between genetic distance and geographical distance was not significant（p>0.05）.Analysis of molecular variance（AMOVA）showed the percentage of genetic variation among and within populations with 11.29%and 88.71%respectively.Strategies of conservation and utilization of genetic diversity of T.sinensis in Anhui province were suggested according to the above results.Results will provide theoretical basis and practical guidance for conservation and utilization of germplasm resources of T.sinensis,and sustainable development of industry of the species in Anhui province.