Study on Persimmon Breeding by Means of Tissue-Cell Culture Systems

1994 Fiscal Year Final Research Report Summary

• Project/Area Number: 05454054
• Research Category: Grant-in-Aid for General Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: 園芸・造園学
• Research Institution: KYOTO UNIVERSITY
• Principal Investigator: SUGIURA Akira Kyoto University, Fac.of Agr.Professor, 農学部, 教授 (00026379)
• Co-Investigator(Kenkyū-buntansha): TAMURA Mihoko Kinki University, Fac.of Biotech-Oriented Sci.& Technol.Assistant, 生物理工学部, 助手 (40258059) ; YONEMORI Keizo Kyoto University, Fac.of Agr.Associate Professor, 農学部, 助教授 (10111949)
• Project Period (FY): 1993 – 1994
• Keywords: Somaclonal variation / Isozyme / Cell fusion / Somatic hybrid / RAPD analysis / Unreduced pollen / Chromosome number / 完全甘ガキ

Research Abstract

Using tissue and cell culture systems for persimmon cultivar improvement, we tried to induce somaclonal variation, to develop somatic hybrids by cell fusion and to obtain 3n plants through rescue culture of immature embryos resulting from pollination with unreduced pollen. The results obtained are summarized as follows :
(1)gamma ray irradiation and PFP treatment were applied to Jiro callus and plantlets were regenerated from the affected celli. The regenerants were compared with the original Jiro plants morphologically and by isozyme analyzes, however, no differences were observed between them. More mutagens need to be tested to induce somaclonal variation in persimmons.
(2) Callus protoplasts of cvs. Jiro and Suruga were fused electrically and cultured for plant regeneration. Regenerants were obtained from 127 callus lines, 22 of which were shown to have twice the nuclear DNA content of the parental calli. RAPD analysis and chromasome counting revealed that the regenerants were somatic hybrids between the two cultivars and had dodecaploid chromosome number of around 2n=180, which is twice the number of parental plants.
(3) Pollen size distribution was examined with several persimmon cultivars. Giant pollen, distinctly larger than the normal pollen, were observed in all the cultivars but the ratio of giant pollen to total pollen varied among cultivars, ranging from about 10% for Zenjimaru and Amayotsumizo, about 2% for Okugosho to less than 1% for the rest cultivars. Nuclear DNA analysis revealed that those giant pollen is unreduced 2n pollen. Unreduced giant pollen was sorted by 62mum nylon mesh filter and used for pollination ; giant pollen of Zenjimaru and Okugosho were crossed for Jiro and Fuyu flowers, respectively. The resultant immature embryos were dissected and cultured in vitro.Chromosome counting demonstrated that the plantlets thus obtained were all nonaploid (2n=9x=135) and their nuclear size was clearly larger than that of hexaploid parents.