Ma X, Gu X-Y, Chen T-T, Chen S-Y, Huang L-K, Zhang X-Q
Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Ya'an, Sichuan, China.
Genet Mol Res. 2013 Mar 11;12(3):3246-55. doi: 10.4238/2013.March.11.4.
The genus Lolium is one of the most important groupings of temperate forage grasses, including about eight recognized species that are native to some temperate and subtropical regions of the northern hemisphere. We examined genetic relationships among 18 accessions representing all Lolium species using RAPD markers. Among 50 random primers that we screened, 13 gave reproducible amplification banding patterns. Each of these 13 primers generated 19-43 scorable fragments. A total of 367 RAPD fragments were detected, of which 95.9% were polymorphic across all the Lolium accessions. Dice's coefficient of dissimilarity ranged from 0.016 to 0.622, which is indicative of substantial genetic variations in these Lolium accessions. A neighbor-joining cluster analysis, with bootstrap permutation, produced an unrooted dendrogram, which grouped 18 accessions into two main clades, supporting high bootstrap values (98 and 96%). The first clade included the self-pollinated species, L. persicum, L. temulentum, L. remotum, and L. subulatum. The cross-pollinated species, i.e., L. multiflorum, L. perenne, L. rigidum, and L. canariense, composed the second clade, in which L. canariense formed a distinct subclade, indicating its higher genetic separation from other allogamous species. The value of r = 0.97 in the Mantel test for cophenetic correlation applied to the cluster analysis indicated the high degree of fit of the accessions to a group. A principal coordinate analysis, whose first three coordinates explained 72.6% of the variation, showed similar groupings as in the cluster analysis. The genetic relationships estimated by the polymorphism of RAPD markers are basically in agreement with those previously inferred with other genetic markers.
黑麦草属是温带饲用禾本科植物中最重要的类群之一，包括约8个公认的物种，原产于北半球的一些温带和亚热带地区。我们使用随机扩增多态性DNA（RAPD）标记研究了代表所有黑麦草物种的18份种质的遗传关系。在我们筛选的50个随机引物中，有13个产生了可重复的扩增条带模式。这13个引物中的每一个都产生了19 - 43个可计分片段。总共检测到367个RAPD片段，其中95.9%在所有黑麦草种质中具有多态性。戴斯相异系数范围为0.016至0.622，这表明这些黑麦草种质中存在大量遗传变异。通过邻接法聚类分析并进行自展置换，生成了一个无根树状图，将18份种质分为两个主要分支，自展值较高（98%和96%）。第一个分支包括自花授粉物种，即波斯黑麦草、毒麦、疏花黑麦草和具芒黑麦草。异花授粉物种，即多花黑麦草、多年生黑麦草、硬直黑麦草和加那利黑麦草，组成了第二个分支，其中加那利黑麦草形成了一个独特的亚分支，表明其与其他异花授粉物种的遗传分化程度较高。应用于聚类分析的共表型相关曼特尔检验中r = 0.97的值表明种质与分组的高度拟合。主坐标分析的前三个坐标解释了72.6%的变异，显示出与聚类分析相似的分组。通过RAPD标记多态性估计的遗传关系与先前用其他遗传标记推断的基本一致。
