EXISTENCE OF SEVERAL POLLINATION CONSTANT NON-ASTRINGENT TYPE PERSIMMONS IN CHINA

Pollination constant non-astringent (PCNA) type persimmons are unique in that they originate in Japan in recent era. The development of the PCNA type cultivars is not so advanced, since only six PCNA type cultivars were reported among more than 1,000 cultivars by a nationwide survey in Japan in 1912. The PCNA type cultivars are known to have very narrow genetic variability, and it causes a serious problem for breeding of new cultivars because of inbreeding depression in breeding population. On the other hand, in 1982, a new PCNA type cultivar, ‘Luotian tianshi’, was reported to be found in Luotian county in Hubei province. This PCNA type cultivar has a different genetic background from Japanese PCNA cultivars, since a cross between ‘Luotian tianshi’ and Japanese PCNA ‘Taishu’ yielded astringent type offspring in addition to PCNA type offspring. This means that the Chinese PCNA cultivar may provide a new strategy for persimmon breeding in the future. In addition to ‘Luotian tianshi’, it is believed that several non-astringent type persimmons exist in the same area of Luotian county in Hubei province where ‘Luotian tianshi’ was found. In this study, we have collected the fruits from several cultivars assumed to be a non-astringent type in Luotian county and determined whether or not those are true non-astringent cultivars of PCNA type by measuring tannin cell sizes of the fruits, which is a good criterion for distinguishing a PCNA type from a non-PCNA type. As a consequence, we could demonstrate that several PCNA type persimmons exist in Luotian county. These cultivars should be an important addition to persimmon germplasm and should have a potential role for breeding in the future.