Abstract

Pepper (Capsicum annuum L.) is one of the most important vegetable crops worldwide. The Balkans, including Bulgaria, are considered as the secondary centre of pepper diversity especially for C. annuum, where local forms with diverse phenotypes and qualities have formed due to the specific agro-climatic conditions and breeding traditions. Evaluation of the genetic diversity and structure of a pepper collection is an important tool for further development of new varieties and the maintenance of sustainable agriculture. In this study, a set of 179 C. annuum accessions collected from different locations in the Balkan Peninsula was genotyped with 21 simple sequence repeat (SSR; microsatellite) markers. In total, 146 alleles were amplified among which the majority were with low frequencies (<5%). The mean He, Ho and PIC for the 21 SSR loci in the whole set were 0.531, 0.249 and 0.483, respectively. Model-based structure analysis divided the collection into 3 main clusters (K = 3) that grouped accessions with distinct fruit traits like shape, size, pungency. Further genetic structure analysis at increasing Ks suggested the presence of sub-clustering within the three main clusters. A Balkan C. annuum mini core collection was constructed based on the allelic diversity and the inferred genetic structure. As far as the mini core collection captured substantial part of the allele richness, genetic and phenotypic diversity of the analysed 176 non-redundant accessions, while maintaining good representativeness, we believe it will be of high interest to pepper breeders and germplasm conservation specialists.

Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.1946428 .

摘要

辣椒（Capsicum annuum L.）是世界上最重要的蔬菜作物之一。巴尔干地区，包括保加利亚，被认为是辣椒多样性的次要中心，尤其是C. annuum，由于特定的农业气候条件和繁殖传统，在那里形成了具有不同表型和品质的地方形态。对辣椒品种的遗传多样性和结构进行评估是进一步开发新品种和维持可持续农业的重要工具。在这项研究中，一组 179 C. annuum从巴尔干半岛不同地点收集的种质用 21 个简单序列重复（SSR；微卫星）标记进行基因分型。总共扩增了 146 个等位基因，其中大多数为低频率（<5%）。整个集合中 21 个 SSR 位点的平均 He、Ho 和 PIC 分别为 0.531、0.249 和 0.483。基于模型的结构分析将集合分为 3 个主要集群 ( K  = 3)，这些集群将具有不同果实特征（如形状、大小、辛辣度）的种质分组。在增加K s 时的进一步遗传结构分析表明在三个主要簇中存在子簇。巴尔干C. annuum基于等位基因多样性和推断的遗传结构构建了迷你核心集合。就迷你核心集合捕获了分析的 176 个非冗余种质的等位基因丰富度、遗传和表型多样性的大部分而言，同时保持良好的代表性，我们相信它会引起辣椒育种者和种质保护专家的高度兴趣。

本文的补充数据可在 https://doi.org/10.1080/13102818.2021.1946428 在线获得。