Studies on the remaining of astringency in relation to decreased capability of seed formation in Japanese persimmon fruits (cv."Nishimura wase")

Research Project

Project/Area Number	61560030
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	園芸・造園学
Research Institution	Gifu University
Principal Investigator	NAKAMURA Mitsuo Faculty of Agriculture, Gifu University, 農学部, 教授 (90021683)
Co-Investigator(Kenkyū-buntansha)	FUKUI Hirokazu Faculty of Agriculture, Gifu University, 農学部, 講師 (20183585)
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥2,000,000 (Direct Cost: ¥2,000,000) Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1986: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	Embryosac development / Tissue culture of Japanese persimmon / 花粉の発芽 / カキ / 授精 / 胚嚢の発育 / 組織培養
Research Abstract	Japanese persimmon (cv."Nishimura wase") is a pollination variant non-astringent (PVNA) type, and de-astringency has not been achived along with decreased capability of seed formation. This decreased capability has been researched from the point of view of male gamete sterility, germination percentage and germination rate of pollen. The development of embryosac from the mother cell to complete formation was investigated in order to understand the relationship between capability of seed formation and female sterility. Embryosac mother cells and tetrasporangii were formed 18 and 12 days before bloom. The embryosac reached maturity 4 days before bloom. There were 3 phases in the development: the first phase, characterized by extension and no enlargement, extended from embryosac mother cell to tetrasporangium, the second phase, characterized by rapid enlargement, extended to the nuclear division of embryosac cells, and the third phase, characterizedby rapid extension, extended to completion of the embryosac. Embryosac abortion and degeneration were observed, at rates reaching 22.5%, after the tetrasporangium or embrvosac cell formation phases. There might be only six fertile embryosacs in a "Nishimura wase" fruit judging from the percentage of embryosac abortions and degenerations. In order to establish thebasic conditions of tissues culture, aseptic shoot cultures were initiated from shoot tips of "Nishimura wase". Shoot tips were excised from dormant axillary buds and cultured in vitro. The best shoot growth was obtained on MS medium containing half strength nitrogen supplemented with Zeatin at 10^<-5> M: BAP or 2ip was ineffective. A five-fold proliferation rate was obtained by single node cutting of elongated shoot. Anther culture, leaf culture and rooting of new shoots cultured using aseptic shoot were also carried out.