Screening of wild superior apple genotypes in north and northeast of Iran using multivariate analysis

Abstract

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.