相关系列扩增多态性分子标记分析部分山药品种遗传多样性

Investigation of Genetic Diversity of Yam Cultivars by SRAP Markers

目的评价山药资源的多样性,为山药品种鉴定及亲缘关系的研究提供科学依据。方法以8个山药栽培居群中的21个山药品种为试材,进行相关系列扩增多态性(SRAP)分析,Popgene 1.32软件计算遗传参数,UPGMA方法构建亲缘关系聚类图。结果相关系列扩增多态性引物共检测到309条清晰条带,其中多态性条带289条;Nei基因多样性指数(H)为0.288 1、Shannon信息指数为(I)0.441 6、居群间基因多样性(Ht)为0.289 1,阐明了山药居群间具有很高的多样性;居群内以河南温县薯蓣居群多样性最高,PPB为35.92%,而福建三明(FJSM)和浙江高楼(ZJRG)山薯居群多样性最低(PPB=0%);居群间基因分化系数Gst为0.865 8、基因流(Nm)为0.077 5,揭示山药居群间遗传变异大于居群内遗传变异;8个居群间的遗传距离在0.049 8～0.487 9,因栽培物种的不同被聚为4类;相关系列扩增多态性标记可将21个山药品种分别归属到薯蓣、参薯、褐苞薯蓣、山薯种内。结论山药品种呈现较高遗传多样性,4种基原山药种间遗传差异较大,相关系列扩增多态性是鉴别我国山药品种的有效方法。

OBJECTIVE To investigate the genetic diversity of yam resources in China aud provide reliable molecular evidences for cuhivar identification and genetic relationship. METHODS Sequence-related amplified polymorphism （SRAP） was applied to de- tect the genetic diversity of 21 yam cuhivars from eight cuhivated populations, Popgene software （version 1.32） was used to calculate genetic parameters, UPGMA clustering was carried out using Mega software （ version 4. 1 ） , and principal component analysis was per- formed with the help of Ntsys-pc （ Version 2. 1 ） program. RESULTS Three hundreds and nine bands were amplified by 20 SRAP primer combinations, of which 289 bands were polymorphic. The Nei＇s gene diversity index （H = 0. 288 1 ） , Shannon＇s information in- dex （ 1 = 0. 441 6） and total genetic diversity （ Ht = 0. 289 1 ） revealed a relatively high genetic diversity level among yam populations. Within populations, HNWX population showed the highest genetic diversity （PPB = 35.92% ） ,whereas the lowest diversity （PPB = 0） was observed in FJSM and ZJRG populations. The genetic differentiation coefficient （ Gst = 0. 865 8 ） and genetic flow （ Nm = 0. 007 5 ） imlicated that the genetic diversity among populations was higher than that of within populations. A well-separated groups coupling with cultivated species was formed according to the genetic distance （GD） ranging from 0. 049 8 -0. 487 9 of the investigated populations. Twenty-one investigated cuhivars could be distinguished and be effectively grouped into four origins, i. e. , Dioscorea opposita ThuMb. , Dioscorea alata Linn. , Dioscorea persimilis Praiu et Burkill. and Dioscoreafordii Prain et Burkill.. CONCLUSION The genetic di- versity level of yam resources is high,and relatively high genetic variation exists among four yam species. SRAP marker is an effective method to identify and classify numerous yam cultivars.