Cultivar Differences in Fruit Deformation of Apple

Abstract

To elucidate mechanisms of fruit deformation in apple, we investigated deformation of 'Fuji', 'Megumi', 'Tsugaru', and 'Orin'. Among these cultivars, no significant difference was nored in the deformation indexes among weight classes, suggesting that they deformed similarly, irrespective of the fruit size. Fruits were easily deformed in the longitudinal direction because the deformation index in that direction was larger than in the transverse direction. The deformation indexes of 'Fuji' were larger than those of other cultivars. The maximum radii of transverse sections of 'Fuji' and 'Orin' appeared near the middle of the two locules, but those of 'Megumi' and 'Tsugaru' appeared near the right locule. Because the position of the maximum radius of transverse section was set as 0°, we investigated those of the minimum radius of transverse section, the minimum longitudinal diameter, and maximum longitudinal diameter. The maximum longitudinal diameter of all cultivars was near the maximum radius of the transverse section. However, the minimum radius of transverse section and minimum longitudinal diameter were at different positions in the four cultivars. The minimum radius of transverse section and minimum longitudinal diameter of 'Fuji' appeared almost symmetrically against the diameter passing through the maximum radius of the transverse section. Key Words：deformation fruit, deformation index, L/D ratio, Malus × domestica Borkh. キーワード：変形果，変形指数，L/D 比，Malus × domestica Borkh.