Being widely considered as one of the most expensive complicated and time-consuming steps, screening and identifying the superior genotypes could be named as the most essential step in breeding programs. In this study, screening of wild superior apple genotypes and genetic diversity of fifty wild apple genotypes were investigated using multivariate analysis. The results showed the coefficients of variation (CVs) of the fruit weight and fruit size were 95.10 and 91.26%, respectively, which were the highest CVs among the quantitative traits. The fruit length had a significant positive correlation with fruit width (r = 0.92**), fruit weight (r = 0.93**), seed length (r = 0.66**) and fruit size (r = 0.68**); whereas, the correlation between the fruit length with pits or bulge at the tip of the fruit (r = − 0.45**) was negative. Principal component analysis revealed that the first three components explained 18.36, 13.78 and 9.62% of total variation, respectively. The results of heatmap clustering according to the traits showed that the second subgroup of the first group (A*II) and the first subgroup of the second group (B*I) had the highest and lowest CVs, respectively. The biplot and heatmap clustering indicated that some genotypes, including N2, N8, N10, N11, N12, N31, N39 and K45 were the superior genotypes. Now that the screened superior genotypes in this study had high values for most of the quantitative traits, they could likely be suitable parents for classical breeding programs. In addition, these genotypes might be satisfactorily used in domestication and even in gene transfer processes. Since this superiority in each genotype varied according to the type of the traits, breeders could use these genotypes as the superior ones for specific breeding purposes. Overall, the findings of this study demonstrated that northeast and north of Iran is one of the diversity centers of apples.

中文翻译：

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伊朗北部和东北部野生优等苹果基因型的多变量分析筛选

被广泛认为是最昂贵复杂和耗时的步骤之一，筛选和鉴定优良基因型可以称为育种计划中最重要的步骤。本研究采用多变量分析方法对野生优等苹果基因型的筛选和50个野生苹果基因型的遗传多样性进行了研究。结果表明，单果重和果实大小的变异系数(CV)分别为95.10%和91.26%，是数量性状中变异系数最高的。果实长度与果实宽度（r = 0.92**）、单果重（r = 0.93**）、种子长度（r = 0.66**）和果实大小（r = 0.68**）呈显着正相关；而果实长度与果实尖端的凹坑或凸起之间的相关性 (r = − 0.45**) 为负相关。主成分分析显示前三个成分分别解释了总变异的 18.36%、13.78% 和 9.62%。根据性状进行热图聚类的结果表明，第一组的第二亚组（A*II）和第二组的第一亚组（B*I）分别具有最高和最低的 CV。双图和热图聚类表明，一些基因型，包括 N2、N8、N10、N11、N​​12、N31、N39 和 K45，是优越的基因型。由于本研究中筛选出的优良基因型对大多数数量性状具有较高的价值，因此它们很可能是经典育种计划的合适亲本。此外，这些基因型可能会令人满意地用于驯化甚至基因转移过程。由于每个基因型的这种优势根据性状的类型而变化，育种者可以将这些基因型用作特定育种目的的优势基因型。总体而言，这项研究的结果表明，伊朗东北部和北部是苹果的多样性中心之一。