Evaluation of Genetic Diversity of Some Pear (Pyrus spp.) Genotypes and Species based on Morphological Characteristics

Pears (Pyrus spp.) belongs to the Rosaceae family، which have been cultivated for more than 3000 years. Pears are among the most important fruits in all the temperate regions in about 50 countries of the world. The objectives of this study were to classify pear genotypes based on qualitative and quantitative characteristic and determination of their genetic distance. Evaluation of genetic diversity of 47 pear accessions including European، Asian and wild species، was started since 2008 in University of Tehran and seed & plant certification & registration institute. Result showed that some traits such as fruit size، maximum fruit diameter، fruit shape، shape of base and apex in leaf had high variability. In this study genotypes were classified according to their characteristics and Ward''s method. Results derived from cluster analysis divided the genotypes into three main groups including European، Asian and wild species. Results of simple correlation analysis showed that leaf blade length and width have positive correlation with fruit weight and size. Results of factor analysis indicated that nine main factors indicated 80% of total variance. First and second factors that were related to leaf and fruit characteristics، described nearly up to 32% of variance.