Determination of Ethylene Synthetic Genotypes Related to Ripening in Japanese Pear Cultivars

Abstract

In Japanese pear (Pyrus pyrifolia Nakai), fruit storage potential is closely related to the maximum level of ethylene production. Previously we identified two markers (A and B) that are linked to the high and moderate ethylene production during fruit ripening respectively and developed the gene diagnosis for the process. This gene diagnosis was used to identify the ethylene synthetic genotypes of Japanese and Chinese pear cultivars by using 43 combinations from 1260 seedlings from which genotypes of 32 cultivars were determined. For example, genotypes of ‘Kosui’, ‘Shinsui’, ‘Chojuro’, ‘Cili’, and ‘Yali’ are aaBb, aaBB, aaBb, AaBB, and AABb, respectively. All the progenies of cultivars, such as ‘Rokugatsu’ (AAbb) and ‘Shinsui’ (aaBB), are predicted to produce high or moderate amounts of ethylene during fruit ripening. If the objective of breeding is storage ability, using these cultivars is inadequate. This information is critical to the breeding program for selection of parents and useful for breeding strategies to improve storage ability in Japanese pear.