R. Najafzadeh - Department of Horticultural Sciences, Faculty of Agriculture, Tarbiat Modares University, Tehran, Islamic Republic of Iran.
K. Arzani - Department of Horticultural Sciences, Faculty of Agriculture, Tarbiat Modares University, Tehran, Islamic Republic of Iran.

Selection of superior chance seedling genotypes is an important task in pear breeding programs. This research was carried out in order to explore and evaluate some of European pear (Pyrus communis L.) chance seedling genotypes that are primarily used as rootstock for the Asian pear (Pyrus serotina Rehd.) in Tarbiat Modares University (TMU) Asian Pear Collection Orchard. After four years visual observations of the genotypes, the evaluation process started on the pre-selected genotypes in order to identify the superior promising individuals during ۲۰۰۹ and ۲۰۱۰ growing seasons. Selected chance seedling genotypes were A۹۵, A۱۰۱, A۱۸۹, A۱۹۵, and A۳۷۴. A local commercial cultivar `Shahmiveh’ was used as a reference and labeled as A۲۳۸ in the evaluation program database. Results showed significant differences among the studied genotypes in most of the evaluated characters. Among the studied genotypes, genotype A۹۵ showed indications of appropriate fruit physicochemical properties and higher fruit quality compared with the reference cultivar. Good fruit aroma as well as a reddish background skin color, highest acidity and lowest pH among the examined genotypes were other superior characters of A۹۵. Based on the measured characters compared with `Shahmiveh' as a good reference commercial Iranian pear cultivar, we conclude that A۹۵ showed superiority and higher rank in flavor, fruit color, and attractiveness. Also, this promising genotype showed a good productivity potential in terms of producing higher yield with a suitable supporting vigor. Further research on the standard rootstocks within the TMU pear breeding program will continue in the framework of final new cultivar release program.

Fruit physicochemical characteristics, Morphological characteristics, Pear breeding program, Promising pear genotype