1995 Fiscal Year Final Research Report Summary
Prevention of peel splitting of loquat
| Project/Area Number |
05556005
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
園芸・造園学
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| Research Institution | University of Tsukuba |
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Principal Investigator |
IWAHORI Shuichi Univ.Tsukuba Inst.Agr.Forestry, Prof., 農林学系, 教授 (00012055)
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| Co-Investigator(Kenkyū-buntansha) |
KUMAMOTO Osamu Kagoshima Pref.Agric.Div., Researcher, 農政部, 技師
TOKITO Toshihiro Kagoshima Fruit Tree Exp.Sta., Chief Researcher, 室長
TATSUDA Yoshinobu Kagoshima Agr.Exp.Sta.Oshima Branch, Chief Researcher, 大島支場, 室長
TOMINAGA Shigeto Kagoshima Univ.Fac.of Agr., Assoc.Prof., 農学部, 助教授 (90164029)
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| Project Period (FY) |
1993 – 1995
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| Keywords | Soil management / Soil water content / Plastic roof culture / Peel splitting / Strength of pulling force / Longitudinal splitting / Amami Oshima Island / Ripening of fruit |
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| Research Abstract |
1. It was observed by light and scanning electron microscopy that for both 'Mogi' and 'Nagasaki-Wase', fruits from Amami Oshima Island which are prone to peel splitting, had the larger cortex cells than those from Tarumizu which scarcely show splitting. Fruits from Oshima also continued transvese growth after cross growth ceased. Splitting occurred only longitudinally and only at peel, not extending to cortex area. It was observerd that 4-6 layrs of cells in the peel split by an increase of turgor pressure of inside cortex cells.
2. Strength of resistance to pulling of peel was considerably weaker in the fruits from Oshima island which are more prone to splitting. Split fruit showed much weaker strength cross-wise compared to that of longitudinal direction.
3. Split fruits seemed to be more advanced stage of ripening as shown by higher coloration and brix and lower acidity.
4. Survey of growers' orchards revealed that less splitting occurred in the orchards of which cultural practices were better in terms of fertilization and soil management, drainage practice and pest and desease management. Improvement of soil physical and chemical properties tended to decrease the occurrence and severity of splitting. Trees under plastic roof showed less occurrence of splitting.
5. These reults strongly suggest that rapid increase of absorption of water from roots during fruit maturation periods resulted in rapid increase in the size of cortex cells and the turgor pressure of these cells also increased, which in turn caused peel splitting if the peel strength was not strong enough to resist the pressure. Application of calcium which is thought to strengthen the peel, and growth regulators to control fruit growth, failed to control the occurrence of splitting. Further research is needed to find out better soil water management, selection of cultivars, the peel of which is stronger and resistant to pulling force, and proper methods of judging ripening strage.
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