The genetic diversity of many Spanish apple collections has been evaluated, but some areas from Central Spain have not been included. In the present work, a set of 41 accessions (33 diploids and 8 triploids) of 23 traditional apple cultivars collected in the region of Madrid and maintained at the IMIDRA collection was analysed with 13 simple sequence repeats (SSRs) to evaluate its diversity. Three reference cultivars (‘Fuji’, ‘Granny Smith’ and ‘Reineta Gris’) were included as reference to align the SSR profiles. The average number of alleles per locus was 7.66, which increased to 8.75 with triploids, and the number of rare alleles was 36. Moreover, the observed heterozygosity (Ho) was 0.74 and the expected heterozygosity (He) was 0.66, indicating disequilibrium. The probability to find two identical individuals was very low (PID = 3.60 × 10−12). After the cluster analysis, 29% of the accessions were found to have redundant profiles. Principal coordinate analysis, clustering and Bayesian model suggested the presence of four well-defined subgroups in the diploid of traditional apple. In clustering, diploid reference cultivars were nested with triploids independently from diploid traditional cultivars. Finally, after comparing profiles and names with other traditional Spanish cultivars, we conclude that the following studied collection shares the ubiquitous accessions from cultivar groups, such as «camuesas», «peros» and ‘Reineta’ but contains novel and uncharacterised cultivars with potential opportunities in breeding programmes and rural development: ‘Agridulce’, ‘Amarillo de El Paular’, ‘Hojancas’, ‘Maílla blanca’, ‘Pepita de melón’ and ‘Rabudas’. As these cultivars were collected in such a small area with environmental distinctiveness, they constitute a singular germplasm reservoir, which deserves to be preserved and more deeply studied.

中文翻译：

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马德里地区（西班牙中部）种植的传统苹果栽培品种 (Malusdomestica Borkh.) 的简单序列重复特征

许多西班牙苹果收藏的遗传多样性已经过评估，但西班牙中部的一些地区尚未包括在内。在目前的工作中，使用 13 个简单序列重复 (SSR) 分析了在马德里地区收集并保存在 IMIDRA 收集中的 23 个传统苹果品种的 41 个种质（33 个二倍体和 8 个三倍体）以评估其多样性。包括三个参考品种（'Fuji'、'Granny Smith' 和'Reineta Gris'）作为参考以对齐 SSR 配置文件。每个基因座的平均等位基因数为 7.66，三倍体增加到 8.75，稀有等位基因数为 36。此外，观察到的杂合度 (Ho) 为 0.74，预期杂合度 (He) 为 0.66，表明不平衡。找到两个相同个体的概率非常低（PID = 3.60 × 10−12）。聚类分析后，发现 29% 的种质具有冗余配置文件。主坐标分析、聚类和贝叶斯模型表明在传统苹果的二倍体中存在四个明确定义的亚群。在聚类中，二倍体参考品种与三倍体独立于二倍体传统品种嵌套。最后，在将简介和名称与其他传统西班牙品种进行比较后，我们得出结论，以下研究的集合共享来自品种组的无处不在的种质，例如 «camuesas»、«peros» 和 'Reineta'，但包含具有潜在机会的新颖和未表征的品种在育种计划和农村发展方面：“Agridulce”、“Amarillo de El Paular”、“Hojancas”、“Maílla blanca”、“Pepita de melón”和“Rabudas”。