Effects of trunk girdling and crop load levels on fruit quality and root elongation in 'Aki Queen' grapevines

Abstract

The effects of trunk girdling and crop load levels on skin color, juice composition, and root elongation of a red table grape, 'Aki Queen' (Vitis labrusca L. x V. vinifera L., tetraploid) were investigated. The treatment of a low crop load with girdling significantly elevated the anthocyanin concentration in berry skin compared to that of a high crop load without girdling. The total soluble solid content of berries was significantly greater in a low crop load with girdling than in other treatments. Titratable acidity was not different among treatments. Root elongation stopped for two weeks as a result of the girdling treatment, regardless of the crop load level. Root elongation after girdle healing was vigorous when the crop load was low.