木荷1代育种群体遗传多样性分析

Genetic Diversity among Breeding Parents of Schima superba Revealed by SSR

木荷为我国亚热带地区主要的珍贵优质阔叶用材树种和生态防护树种。利用筛选的14对多态性强的SSR引物,对木荷1代育种群体中来自15个产地133个亲本进行遗传多样性分析,为其优异种质资源保存、杂交亲本选配及新种质创制提供科学依据。结果表明:14对引物共扩增86个位点,每对引物检测到的等位基因数(Na)变异范围为2 11个,平均等位基因数(Na)为6.14个,平均有效等位基因数(Ne)为3.23个,平均观察杂合度(Ho)为0.572 0,平均Shannon信息指数(I)和平均Nei’s基因多样性指数(Nei)分别为1.224 7和0.599 0,说明木荷1代育种群体具有丰富的遗传多样性,其中,福建建瓯产地遗传多样性最高,浙江遂昌产地遗传多样性最低。木荷1代育种群体中成对亲本间遗传距离为0.023 3 1.633 8,平均为0.606 7。不同产地遗传多样性与纬度呈显著的负相关关系(r=-0.516 2,p=0.048 9)。通过UPGMA聚类,可将133个育种亲本分成3个类群,其中,类群3又分为4个亚类群。木荷亲本选配时,应充分考虑优树的产地来源。

Schima superba is a representative, widely distributed species of broadleaf tree found in the subtropical forests of southern China. It valued commercially for its timber and ecology using. We used SSR molecular tech- nique to investigate the genetic diversity and structure of S. superba, which would formulate the breeding strategy and provide insight for selecting breeding parents. 14 pairs of SSR primers were selected and 133 individuals came from 15 provenances were conducted in this experiment. The results showed that 86 polymorphic loci with alleles ranged from 2 to 11 were detected. The observed number of alleles, number of effect alleles, observed heterozygosi- ty, Shannon information index and Nei＇ s gene diversity were 6.14, 3.23, 0.572 0, 1. 224 7 and 0. 599 0 respectively. The breeding parents of S. superba held higher genetic diversity and the genetic diversity in Jian＇ ou of Fujian Province was highest, but it was lowest in Suichang of Zhejiang Province. The genetic difference was large among the individuals of the breeding parents of S. superba. The genetic distance was ranged from 0. 023 3 to 1. 633 8 with the average value of 0.606 7. Shannon＇ s index of breeding parents was significantly negative with the lati- tudes of the seed sources （r = -0. 516 2, p =0. 048 9）. The UPGMA cluster analysis showed that 133 individuals clustered into three groups and the third group could be divided into 4 sub-groups. It is important to consider the or- igin of the trees when selected the parents for hybridization.