2011 年 55 巻 4 号 p. 129-134
Less acid passion fruit has being increasingly demanded for fresh fruit consumption recently. To examine the effect of matter distribution into fruit on fruit acidity, three different fruit loads, heavy, medium, and light, were established, and fruit acidity was measured. The heavy-fruit-load treatment represented the utmost level of fructified load, and plants were not able to bear further fruit. The numbers of fruits in the medium- and light-load treatments were 2/3 and 1/3 of those in the heavy-load treatment. Acid content increased remarkably as fruit load increased. The acid content of ripened fruit in the light-load treatment was 1.77 %, which was markedly lower than that in the heavy- (2.50 %) and medium- (2.16 %) load treatments. In the heavy-load treatment, Brix sugar content was lower than in the other two treatments, although the difference was small. The sugar/acid ratio, which reflects savor, improved markedly as fruit load decreased. Fruit weight and dimensions increased as fruit load decreased, and the effect of fruit load on fruit weight was more significant than the effect on fruit dimensions. The acid content of passion fruit was found to decrease as matter distribution into fruit increased. These results indicate that a reduction in fruit load by more than 1/3 from the bearing capacity might be effective to produce substantially less-acid passion fruit.