Department of Horticulture Sciences, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.
Temperate Fruits Research Center, Horticultural Science Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
PLoS One. 2021 Mar 16;16(3):e0248623. doi: 10.1371/journal.pone.0248623. eCollection 2021.
Iran is a center of origin and diversity for walnuts (Juglans regia L.) with very good potential for breeding purposes. The rich germplasm available, creates an opportunity for study and selection of the diverse walnut genotypes. In this study, the population structure of 104 Persian walnut accessions was assessed using AFLP markers in combination with phenotypic variability of 17 and 18 qualitative and quantitative traits respetively. The primers E-TG/M-CAG, with high values of number of polymorphic bands, polymorphic information content, marker index and Shannon's diversity index, were the most effective in detecting genetic variation within the walnut germplasm. Multivariate analysis of variance indicated 93.98% of the genetic variability was between individuals, while 6.32% of variation was among populations. A relatively new technique, an advanced maximization strategy with a heuristic approach, was deployed to develop the core collection. Initially, three independent core collections (CC1-CC3) were created using phenotypic data and molecular markers. The three core collections (CC1-CC3) were then merged to generate a composite core collection (CC4). The mean difference percentage, variance difference percentage, variable rate of coefficient of variance percentage, coincidence rate of range percentage, Shannon's diversity index, and Nei's gene diversity were employed for comparative analysis. The CC4 with 46 accessions represented the complete range of phenotypic and genetic variability. This study is the first report describing development of a core collection in walnut using molecular marker data in combination with phenotypic values. The construction of core collection could facilitate the work for identification of genetic determinants of trait variability and aid effective utilization of diversity caused by outcrossing, in walnut breeding programs.
伊朗是核桃（Juglans regia L.）的起源和多样性中心，具有很好的育种潜力。丰富的种质资源为研究和选择不同的核桃基因型提供了机会。本研究采用 AFLP 标记结合 17 个和 18 个定性和定量性状的表型变异，评估了 104 个波斯核桃资源的群体结构。引物 E-TG/M-CAG 在检测核桃种质遗传变异方面效果最好，具有多态带数、多态信息含量、标记指数和 Shannon 多样性指数高的特点。多变量方差分析表明，遗传变异的 93.98%存在于个体之间，而 6.32%的变异存在于群体之间。一种相对较新的技术，一种具有启发式方法的高级最大化策略，被用来开发核心种质。最初，使用表型数据和分子标记创建了三个独立的核心种质（CC1-CC3）。然后将这三个核心种质（CC1-CC3）合并生成一个综合核心种质（CC4）。使用平均差异百分比、方差差异百分比、变异系数比率、范围百分比一致性、Shannon 多样性指数和 Nei 的基因多样性进行比较分析。CC4 有 46 个个体，代表了表型和遗传变异的完整范围。本研究首次报道了利用分子标记数据结合表型值开发核桃核心种质的情况。核心种质的构建可以促进鉴定性状变异性的遗传决定因素的工作，并有助于在核桃育种计划中有效利用杂交引起的多样性。
