Phenotypic characterization of Pyrus glabra Boiss. and P. syriaca Boiss.: implications for conservation and utilization

Key message

Basic comparative information was generated on phenotypic diversity of two important pear species (Pyrus glabra and P. syriaca) and superior genotypes were selected for conservation and utilization purposes.

Abstract

The first and most important step for the conservation and utilization of any wild germplasm is phenotypic characterization. By adopting a comparative approach and applying multivariate statistical analysis, this study aimed to estimate the extent of variations in vegetative and reproductive traits of Pyrus glabra and P. syriaca, located in the south of the Zagros region, Iran. For this purpose, 30 genotypes of each species were evaluated in their natural habitats. The results showed that both species have a high level of diversity in many traits, including leaf area, fruit weight, total soluble solids/titratable acids (TSS/TA) ratio, and total phenol content. P. glabra had more traits with high coefficients of variation than P. syriaca. In both species, correlation analysis showed that leaf length and width, leaf petiole length, and leaf area correlated positively with fruit traits such as fruit weight, fruit diameter, total soluble solids, and titratable acidity. Based on the Ward method, a cluster analysis classified the genotypes of each species into three main groups at distances of 10. Principal component analysis revealed that, in both species, the first three factors mainly comprised quantitative traits of fruits and leaves, explaining about 44% of the variance. The results of cluster analysis, bi-plot illustration, correlation analysis, and principle component analysis (PCA) were in general agreement in both species. The genotypes were classified into two main categories, reflecting known morphological differences within each species and their geographical proximity. While considering a trait-syndrome approach, some genotypes of P. syriaca, with large fruit size, high ascorbic acid content, antioxidant activity, total phenol content, and a balanced TSS/TA ratio, were selected as potential ideotypes and parent materials for drought resistance and fruit quality traits. The superior genotypes can contribute to the current goals of pear breeding programs.