Munankarmi Nabin Narayan, Rana Neesha, Bhattarai Tribikram, Shrestha Ram Lal, Joshi Bal Krishna, Baral Bikash, Shrestha Sangita
Central Department of Biotechnology, Tribhuvan University (CDBt-TU), GPO Box 44613, Kirtipur, Kathmandu, Nepal.
Molecular Biotechnology Unit, Faculty of Science, Nepal Academy of Science and Technology (NAST), GPO Box 3323, Khumaltar, Lalitpur, Nepal.
Plants (Basel). 2018 Jun 12;7(2):46. doi: 10.3390/plants7020046.
Acid lime ( (Christm.) Swingle) is an important fruit crop, which has high commercial value and is cultivated in 60 out of the 77 districts representing all geographical landscapes of Nepal. A lack of improved high-yielding varieties, infestation with various diseases, and pests, as well as poor management practices might have contributed to its extremely reduced productivity, which necessitates a reliable understanding of genetic diversity in existing cultivars. Hereby, we aim to characterize the genetic diversity of acid lime cultivars cultivated at three different agro-ecological gradients of eastern Nepal, employing PCR-based inter-simple sequence repeat (ISSR) markers. Altogether, 21 polymorphic ISSR markers were used to assess the genetic diversity in 60 acid lime cultivars sampled from different geographical locations. Analysis of binary data matrix was performed on the basis of bands obtained, and principal coordinate analysis and phenogram construction were performed using different computer algorithms. ISSR profiling yielded 234 amplicons, of which 87.18% were polymorphic. The number of amplified fragments ranged from 7–18, with amplicon size ranging from ca. 250–3200 bp. The Numerical Taxonomy and Multivariate System (NTSYS)-based cluster analysis using the unweighted pair group method of arithmetic averages (UPGMA) algorithm and Dice similarity coefficient separated 60 cultivars into two major and three minor clusters. Genetic diversity analysis using Popgene ver. 1.32 revealed the highest percentage of polymorphic bands (PPB), Nei's genetic diversity (H), and Shannon's information index (I) for the Terai zone (PPB = 69.66%; H = 0.215; I = 0.325), and the lowest of all three for the high hill zone (PPB = 55.13%; H = 0.173; I = 0.262). Thus, our data indicate that the ISSR marker has been successfully employed for evaluating the genetic diversity of Nepalese acid lime cultivars and has furnished valuable information on intrinsic genetic diversity and the relationship between cultivars that might be useful in acid lime breeding and conservation programs in Nepal.
酸橙（(Christm.) Swingle）是一种重要的水果作物，具有很高的商业价值，在代表尼泊尔所有地理景观的77个区中的60个区都有种植。缺乏改良的高产品种、遭受各种病虫害以及管理不善可能导致其产量极低，因此有必要可靠地了解现有品种的遗传多样性。在此，我们旨在利用基于聚合酶链式反应（PCR）的简单序列重复区间（ISSR）标记，对尼泊尔东部三个不同农业生态梯度种植的酸橙品种的遗传多样性进行表征。总共使用了21个多态性ISSR标记来评估从不同地理位置采集的60个酸橙品种的遗传多样性。基于获得的条带对二元数据矩阵进行分析，并使用不同的计算机算法进行主坐标分析和构建聚类图。ISSR分析产生了234个扩增片段，其中87.18%是多态性的。扩增片段的数量范围为7 - 18个，扩增子大小范围约为250 - 3200 bp。使用非加权算术平均法（UPGMA）算法和Dice相似系数，基于数值分类和多变量系统（NTSYS）的聚类分析将60个品种分为两个主要聚类和三个次要聚类。使用Popgene ver. 1.32进行的遗传多样性分析显示，特赖地区的多态性条带百分比（PPB）、Nei氏遗传多样性（H）和香农信息指数（I）最高（PPB = 69.66%；H = 0.215；I = 0.325），而高山区在这三者中最低（PPB = 55.13%；H = 0.173；I = 0.262）。因此，我们的数据表明，ISSR标记已成功用于评估尼泊尔酸橙品种的遗传多样性，并提供了关于内在遗传多样性以及品种间关系的有价值信息，这可能对尼泊尔的酸橙育种和保护计划有用。
