Relationship between Early Fruit Growth and Harvest Fruit Quality in Satsuma Mandarin
1982 Volume 51 Issue 3 Pages 263-269
Details
1982 Volume 51 Issue 3 Pages 263-269
Early fruit growth was studied in realtion to the final fruit quality in satsuma mandarin (Citrus unshiu Marc.). Flowers were classified into two groups of leafy and leafless ones, and flowers of each group were further classified into early and late ones and inside and outside ones according to their flowering date and position in the canopy, respectively. Microscopic observations on the development of the juice sacs in the locules was also conducted.
1. The percentage of physiological fruit drop was 80-90 percent for the fruit from leafless flowers and about 40 percent for the fruit from leafy flowers. Among the leafless fruit, fruit drop was about 10 percent higher for the fruit from early flowers than from late flowers. Among the leafy fruit, however, there was little difference due to the flowering date.
2. The transverse diameter of fruit was always larger and its increasing rate was also larger for the fruit from leafy flowers than for the fruit from leafless flowers. The fruit from late flowers were smaller in the transverse diameter than the fruit from early flowers at the early stage of their growth but the difference gradually disappeared later. While the increasing rate of transverse diameter was higher for late-flowered fruit until 40 dates after anthesis.
3. Juice sac primordia appeared on the inner wall of the locules at anthesis, that is, May 10 for the early flowers and May 20 for the late flowers. The locules of both early- and late-flowered fruit were filled with juice sacs on June 19, which was 40 and 30 days after anthesis for early- and late-flowered fruit, respectively.
4. Leafy fruit, early-flowered fruit and outside fruit were larger, showed more advanced coloration, higher in Brix and lower in acid content as compared with leafless fruit, late-flowered fruit and inside fruit, respectively.
5. From these results, it would appear that the percentage of high quality fruit can be increased by thinning of small fruit from early July to early August which would be otherwise harvested as low quality fruit.
