Hao Chenyang, Wang Lanfen, Zhang Xueyong, You Guangxia, Dong Yushen, Jia Jizeng, Liu Xu, Shang Xunwu, Liu Sancai, Cao Yongsheng
Key Laboratory of Crop Germplasm & Biotechnology, MOA, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Sci China C Life Sci. 2006 Jun;49(3):218-26. doi: 10.1007/s11427-006-0218-z.
Genetic diversity of 1680 modern varieties in Chinese candidate core collections was analyzed at 78 SSR loci by fluorescence detection system. A total of 1336 alleles were detected, of which 1253 alleles could be annotated into 71 loci. For these 71 loci, the alleles ranged from 4 to 44 with an average of 17.6, and the PIC values changed from 0.19 to 0.89 with an average of 0.69. (1) In the three genomes of wheat, the average genetic richness was B>A>D, and the genetic diversity indexes were B>D>A. (2) Among the seven homoeologous groups, the average genetic richness was 2=7>3>4>6>5>1, and the genetic diversity indexes were 7>3>2>4>6>5>1. As a whole, group 7 possessed the highest genetic diversity, while groups 1 and 5 were the lowest. (3) In the 21 wheat chromosomes, 7A, 3B and 2D possessed much higher genetic diversity, while 2A, 1B, 4D, 5D and 1D were the lowest. (4) The highest average genetic diversity index existed in varieties bred in the 1950s, and then it declined continually. However, the change tendency of genetic diversity among decades was not greatly sharp. This was further illustrated by changes of the average genetic distance between varieties. In the 1950s it was the largest (0.731). Since the 1960s, it has decreased gradually (0.711, 0.706, 0.696, 0.695). The genetic base of modern varieties is becoming narrower and narrower. This should be given enough attention by breeders and policy makers.
利用荧光检测系统，在78个SSR位点对中国候选核心种质库中1680份现代品种的遗传多样性进行了分析。共检测到1336个等位基因，其中1253个等位基因可注释到71个位点。对于这71个位点，等位基因数从4个到44个不等，平均为17.6个，PIC值从0.19到0.89不等，平均为0.69。（1）在小麦的三个基因组中，平均遗传丰富度为B>A>D，遗传多样性指数为B>D>A。（2）在七个同源群中，平均遗传丰富度为2=7>3>4>6>5>1，遗传多样性指数为7>3>2>4>6>5>1。总体而言，第7组遗传多样性最高，而第1组和第5组最低。（3）在21条小麦染色体中，7A、3B和2D的遗传多样性较高，而2A、1B、4D、5D和1D的遗传多样性最低。（4）平均遗传多样性指数在20世纪50年代培育的品种中最高，随后持续下降。然而，不同十年间遗传多样性的变化趋势并不十分明显。品种间平均遗传距离的变化进一步说明了这一点。20世纪50年代平均遗传距离最大（0.731）。自20世纪60年代以来，它逐渐下降（0.711、0.706、0.696、0.695）。现代品种的遗传基础正变得越来越窄。育种者和政策制定者应予以足够重视。
