Abstract. Relationships among climate changes, early frost, and fruit growth were studied during the final month to harvest of late-maturing 'Fuyu' persimmon (Diospyros kaki) to assess the changes in fruit characteristics during this critical period. The heavy frost on Nov. 16 defoliated more than 70% of the leaves, but with little damage on the fruits. However, all the leaves were defoliated by the heavy frost on Nov. 20, and all the fruits were cold-damaged by -3.3℃ on Nov. 21. Fruit weight increased by 8-25 g per week from Oct. 25 (142 days after full bloom) to Nov. 15, reaching to 250 g, but it decreased by 3-4 g per week after the frost. Hunter a value of fruit skin gradually increased until the last harvest on Nov. 29 with a temporary halt in early Nov. when temperature was high, whereas fruit firmness rapidly decreased after the frost on Nov. 21. Fruit soluble solids were 15.7-16

A long-term field experiment under different fertilization treatments had been conducted to explore the effects of rice yield and soil chemical properties from 1978 to 2008 in Suwon, Korea. The paddy was applied eight fertilization treatments which were F0 (no fertilizer), PK (phosphorous and potassium), NK (nitrogen and potassium), NP (nitrogen and phosphorous), NPK (nitrogen, phosphorus and potassium), NPKC (NPK with compost), NPKS (NPK with straw) and NPKL (NPK with lime). Results of 31 years experiment showed that yield index (the ratio of yield in each treatment to NPK) was the lowest in F0 (0.52) and the highest in NPKC (1.18). Yield index was gradually increased in NPKC but decreased in F0 and NK. The yield index of PK, NP, NPKS and NPKL were not changed long-term treatment. Soil acidity of NPKL showed the highest with pH 7.9, and that of other treatments ranged from pH 6.3 to 6.8. Available phosphorous content of soil was increased in all plots by long-term fertilization, was the highest in PK and NPKC. Soil organic matter was higher in NPKC (1.8%) and NPKS (1.8%) than other treatments (1.3~1.4%) in the early experiment, but that was remarkably increased in only NPKC (2.5%) according to annual long-term application. Thus we suggest that annual compost application with optimum NPK could make stable and sustainable rice production.

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This study investigated the relationships between fruit size and other fruit quality components in "Fuyu" persimmon. The flower buds were thinned to leave one or two buds per bearing shoot in mid-May. All fruits were harvested on November 12 and they were divided into six size classes by fresh weight. The length/diameter (L/D) ratio and flesh firmness significantly decreased as fruit size increased. Large fruits had a redder skin color with more seeds than small ones. There was a strong negative relationship between fruit size and the L/D ratio (R 2 = 0.741, p ≤ 0.01) and firmness (R 2 = 0.604, p ≤ 0.01). Skin color and number of seeds per fruit were positively related to fruit size, especially skin color where the relationship was highly positive (R 2 = 0.771, p ≤ 0.01). There was a weak, but non-significant positive relation between fruit size and soluble solids. P, K, and Ca concentrations significantly decreased with increasing fruit size. Highly negative relationships were found between fruit size and fruit P (R 2 = 0.393, p ≤ 0.01), K (R 2 = 0.446, p ≤ 0.01), and Ca (R 2 = 0.417, p ≤ 0.01) concentrations. Fruit N and Mg concentrations were not affected by fruit size. It was concluded that fruit size is related to shape, coloration, flesh firmness, and number of seeds per fruit, affecting concentrations of some mineral nutrients in fruits.

No abstract