Fruit Characteristics of Late Maturing Mandarin Cultivars Over-wintered on Tree inside Plastic House

摘要

The fruit characteristics of late maturing mandarin cultivars that were top-grafted on inter stocks of satsumamandarin (Miyagawa Wase) and over-wintered on trees in plastic house were investigated in this study. Most cultivars sprouted on March 30, 5to 8 days later than 'Sagamandarin', which sprouted on March 23. Similarly, all cultivars bloomed on May 7 except for 'Sagamandarin', which flowered on May 1. Fruit index varied slightly among cultivars. Peel thickness of 'Aoshima', 'Imamura', 'Juman', 'Silverhill' cultivars were thicker than that of 'Miyagawa Wase'. The pulp ratio was 70% in 'Aoshima', 'Imamura'.; 'Juman', 'Nankan No. 20', 'Sagamandarin', 'Silverhill' cultivars, which was slightly lower than the pulp ratio of 'Miyagawa Wase'. All cultivars studied had numerically high peel coloring values at harvesting time on mid February, which indicated that the cultivars evaluated are late maturing and the later the fruits are harvested, the better the quality. Soluble solid content (SSC) which isone of the most important indicators of fruit quality had values of 12.0, 12.9, 12.2, 12.9, and 13.7 deg Bx in 'Aoshima', 'Juman', 'Kunou', 'Ohtsu No. 4', and 'Sagamandarin'. SSC of these cultivars were higher by 1.3-3癇x compared with that of 'MiyagawaWase', which is the major commercial cultivar grown in this cropping system of over-wintering inside the plastic film house. In addition to aforementioned cultivars, other cultivars had slightly higher SSC although folly matured and harvested late. 'Nankan No. 20' and 'Miyagawa' had lower acidity while 'Jutaro' and 'Ohtsu No. 4' had higher acidity of 1.5 and 1.4%, respectively.