中国华北和东北地区杏种质资源遗传多样性分析

Genetic Diversity of the Apricot Germplasms from North & Northeast China

利用核果类8条染色体连锁群上均匀分布的55对SSR引物,对中国华北和东北地区的51份杏(Prunus armeniaca L.)种质进行贝叶斯聚类、遗传多样性和稀有位点分析。结果表明,贝叶斯聚类K=5时,反映了最可能的5个遗传基础构成。在整体遗传水平上,华北和东北地区的杏种质所涵盖的遗传基础构成相似,但也有一定的差异。依据遗传成分比例划分亚组,并通过遗传多样性比较发现,亚组Ⅱ和Ⅴ的种质多来自东北地区,其他亚组的种质多来自华北地区。亚组Ⅳ的Shannon’s多样性指数(I)最高,为1.568,亚组Ⅴ最低(1.181)。亚组间遗传距离(Genetic distance)平均为0.262,亚组Ⅲ与亚组Ⅳ间的遗传距离最短(0.156),亚组Ⅴ与杂合组的遗传距离最长(0.398),亚组Ⅴ同其他亚组间的遗传渗透和交流频率最低,其次为亚组Ⅱ。主坐标分析表明,大多数华北和东北地区的种质个体间遗传差异较小,归入东北地区的亚组Ⅱ和亚组Ⅴ的遗传基础差别明显。对供试材料的稀有等位基因位点统计和比较发现,86.27%供试杏种质检测到140个稀有位点,平均每个样品2.74个。种质‘李蜜杏’含稀有位点数最多(11个),占其位点总数的10%;而‘吨葫芦’、‘新世纪’和‘关音脸’等种质中未检测到稀有位点。

In this study,we revealed the genetic diversity and structuration of 51 apricot accessions from North and Northeast China.Bayesian clustering of these apricot accessions was addressed using 55 microsatellites that were widely distributed across the Texas×Earlygold linkage map.The most relevant levels of different genetic basis(the number of groups)were detected at K=5,representing the highestvalue ofΔK.Thus,we proposed there were a total of five genetic basis of cultivated apricots from both North and Northeast China.The most representatives of the Northeast Chinese apricot were found in the clustering groupⅡandⅤ.Genetic diversity was estimated on these five clustering groups in term of Shannon’s index(I),which was 1.305 on average,and ranged from 1.181 in groupⅤto 1.568 in groupⅣ.The Nei’s genetic distance matrix showed the highest pairwise value of 0.398 between groupⅤand mixture group,and the lowest pairwise value of 0.156 between groupⅢand groupⅣ.The averaged pairwise Nei’s genetic distance was 0.262.Furthermore,principal coordinate analysis also showed a clear difference between groupⅡandⅤ,even there was little genetic variant among North and Northeast apricots.We selected forty-one available microsatellites and obtained a total of 140 rare alleles,with an average of 2.74 for each.The highest number of rare alleles was found in‘Limixing’accession,represented 10%total variation.However,there was no rare alleles detected in a few apricot accessions,e.g.‘Dunhulu’,‘Xinshiji’and‘Guanyinlian’.