Dipartimento di Agricoltura, Alimentazione e Ambiente, University of Catania, Catania, Italy.
Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria, Centro di Ricerca Olivicoltura, Frutticoltura e Agrumicoltura (CREA-OFA), Acireale, Italy.
PLoS One. 2018 Jun 1;13(6):e0198512. doi: 10.1371/journal.pone.0198512. eCollection 2018.
The pear (genus Pyrus) is one of the most ancient and widely cultivated tree fruit crops in temperate climates. The Mount Etna area claims a large number of pear varieties differentiated due to a long history of cultivation and environmental variability, making this area particularly suitable for genetic studies. Ninety-five pear individuals were genotyped using the simple sequence repeat (SSR) methodology interrogating both the nuclear (nDNA) and chloroplast DNA (cpDNA) to combine an investigation of maternal inheritance of chloroplast SSRs (cpSSRs) with the high informativity of nuclear SSRs (nSSRs). The germplasm was selected ad hoc to include wild genotypes, local varieties, and national and international cultivated varieties. The objectives of this study were as follows: (i) estimate the level of differentiation within local varieties; (ii) elucidate the phylogenetic relationships between the cultivated genotypes and wild accessions; and (iii) estimate the potential genetic flow and the relationship among the germplasms in our analysis. Eight nSSRs detected a total of 136 alleles with an average minor allelic frequency and observed heterozygosity of 0.29 and 0.65, respectively, whereas cpSSRs allowed identification of eight haplotypes (S4 Table). These results shed light on the genetic relatedness between Italian varieties and wild genotypes. Among the wild species, compared with P. amygdaliformis, few P. pyraster genotypes exhibited higher genetic similarity to local pear varieties. Our analysis revealed the presence of genetic stratification with a 'wild' subpopulation characterizing the genetic makeup of wild species and the international cultivated varieties exhibiting the predominance of the 'cultivated' subpopulation.
梨（梨属）是温带地区最古老和广泛种植的果树之一。埃特纳山地区声称拥有大量因长期种植和环境变化而分化的梨品种，使该地区特别适合进行遗传研究。使用简单重复序列（SSR）方法对 95 个梨个体进行了基因分型，该方法同时检测了核（nDNA）和叶绿体 DNA（cpDNA），将叶绿体 SSRs（cpSSRs）的母系遗传与核 SSRs（nSSRs）的高信息量相结合。种质是专门选择的，包括野生基因型、地方品种、国家和国际栽培品种。本研究的目的如下：（i）估计地方品种内的分化水平；（ii）阐明栽培基因型与野生品系之间的系统发育关系；（iii）估计潜在的遗传流和我们分析中种质之间的关系。8 个 nSSR 共检测到 136 个等位基因，平均小等位基因频率和观察杂合度分别为 0.29 和 0.65，而 cpSSR 允许鉴定 8 个单倍型（S4 表）。这些结果揭示了意大利品种和野生基因型之间的遗传相关性。在野生种中，与 P. amygdaliformis 相比，少数 P. pyraster 基因型与当地梨品种的遗传相似性更高。我们的分析揭示了存在遗传分层，一个“野生”亚群特征是野生种的遗传构成，而国际栽培品种则表现出“栽培”亚群的优势。
