Homogeneity of Japanese persimmon [Diospyros kaki] 'Saijo' old trees distributed in Chugoku district [Japan] as revealed by morphological characters and RFLP analysis

'Saijo' is a local variety of Japanese persimmon (Diospyros kaki Thunb.) with a long history of cultivation. Since 'Saijo' displays several genetic variations, it remained to be determined whether these variations were derived from bud mutation or crossing. In the present study, we examined 13 varieties of persimmon, including 'Fuyu', by RFLP analysis, using fragments of genes for ethylene receptors (ETR and ERS) and 1-aminocyclopropane-1-carboxylase oxidase (ACCO) probes, and EcoRI and HindIII as restriction enzymes. As a result, based on their band patterns, we could distinguish 10 persimmon varieties, excluding bud-sports. By RFLP analysis, we analyzed six strains of 'Saijo', namely the 'Izumo strain', the 'Iwami strain', the 'Kute strain', the 'Hinomisaki strain', and the 'A' and 'B' strains, identified by Kono et al. (1980) and we also analyzed 15 old trees distributed in the Chugoku district under the variety name ' Saijo'. The band patterns of 14 old trees excluding the tree in Takamiya-cho were the same as the patterns of the trees of the 'Izumo','Iwami' and 'Hinomisaki' strains. The analysis revealed the homogeneity of 14 old trees. Based on the estimated ages of the old trees, 'Saijo' was considered to have spread to various areas by grafting, during the Muromachi era and the Edo era (15-19 C). Most of the band patterns of the old tree in Takamiya-cho, were different from those of the other old trees, and their morphological characters were also different. Therefore, it was suggested that the old tree in Takamiya-cho may not be a 'Saijo' variety. Based on RFLP analysis, it was assumed that the 'Izumo strain', the 'Iwami strain' and the 'Hinomisaki strain' corresponded to the original 'Saijo' variety, while the 'A' and 'B' strains were extremely close strains to 'Saijo', probably derived from crossing, and the 'Kute strain' was derived from crossing or was not a 'Saijo' variety.