Assefa Kebebew, Merker Arnulf, Tefera Hailu
Debre Zeit Agricultural Research Center, Debre Zeit, Ethiopia.
Hereditas. 2003;139(3):174-83. doi: 10.1111/j.1601-5223.2003.01800.x.
The DNA polymorphism among 92 selected tef genotypes belonging to eight origin groups was assessed using eight inter simple sequence repeat (ISSR) primers. The objectives were to examine the possibility of using ISSR markers for unravelling genetic diversity in tef, and to assess the extent and pattern of genetic diversity in the test germplasm with respect to origin groups. The eight primers were able to separate or distinguish all of the 92 tef genotypes based on a total of 110 polymorphic bands among the test lines. The Jaccard similarity coefficient among the test genotypes ranged from 0.26 to 0.86, and at about 60 % similarity level the clustering of this matrix using the unweighted pair-group method based on arithmetic average (UPGMA) resulted in the formation of six major clusters of 2 to 37 lines with further eight lines remaining ungrouped. The standardized Nei genetic distance among the eight groups of origin ranged between 0.03 and 0.32. The UPGMA clustering using the standardized genetic distance matrix resulted in the identification of three clusters of the eight groups of origin with bootstrap values ranging from 56 to 97. The overall mean Shannon Weaver diversity index of the test lines was 0.73, indicating better resolution of genetic diversity in tef with ISSR markers than with phenotypic (morphological) traits used in previous studies. This can be attributed mainly to the larger number of loci generated for evaluation with ISSR analysis as compared to the few number of phenotypic traits amenable for assessment and which are further greatly affected by environment and genotype x environment interaction. Analysis of variance of mean Shannon Weaver diversity indices revealed substantial (P < or = 0.05) variation in the level of diversity among the eight groups of origin. In conclusion, our results indicate that ISSR can be useful as DNA-based molecular markers for studying genetic diversity and phylogenetic relationships, DNA fingerprinting for the identification of varieties or cultivars, and also for genome mapping in tef.
使用8个简单重复序列区间（ISSR）引物评估了属于8个起源群体的92个选定的画眉草基因型之间的DNA多态性。目的是研究使用ISSR标记揭示画眉草遗传多样性的可能性，并评估测试种质相对于起源群体的遗传多样性程度和模式。这8个引物能够根据测试品系间总共110条多态性条带区分所有92个画眉草基因型。测试基因型间的杰卡德相似系数在0.26至0.86之间，在约60%的相似性水平下，使用基于算术平均值的非加权配对组方法（UPGMA）对该矩阵进行聚类，形成了6个主要聚类，包含2至37个品系，另有8个品系未分组。8个起源群体间的标准化奈氏遗传距离在0.03至0.32之间。使用标准化遗传距离矩阵进行UPGMA聚类，鉴定出8个起源群体中的3个聚类，自展值在56至97之间。测试品系的总体平均香农-韦弗多样性指数为0.73，表明与之前研究中使用的表型（形态）性状相比，ISSR标记在画眉草遗传多样性解析方面效果更好。这主要可归因于与少数可用于评估且受环境和基因型×环境互作影响更大的表型性状相比，ISSR分析产生了更多用于评估的位点。对平均香农-韦弗多样性指数的方差分析表明，8个起源群体间的多样性水平存在显著（P≤0.05）差异。总之，我们的结果表明，ISSR可作为基于DNA的分子标记用于研究遗传多样性和系统发育关系、进行品种或栽培品种鉴定的DNA指纹分析，以及画眉草的基因组作图。
