環状はく皮処理がブドウ'ピオーネ'の果実品質に及ぼす影響(栽培管理・作型)  [in Japanese] Effects of Girdling on Berry Quality of 'Pione' Grapevine(Crop Production & Cropping Type)  [in Japanese]

比較的強樹勢な'ピオーネ'樹の環状はく皮処理が成熟期の果実品質に及ぼす影響について経時的に調査した.主枝処理では, 全調査期間を通じて果粒重に有意差が認められなかったのに対し, 果皮色と糖度ははく皮区が対照区よりも有意に高かった.果皮アントシアニン含量の推移は, 果皮色と同様にはく皮区が対照区よりも有意に高かった.遊離酸含量の低下とβ比(酒石酸/リンゴ酸)の上昇については, 処理区間で有意差が認められなかった.主幹処理では, 対照樹に比べてはく皮樹の着色が高く推移した.盆前の8月11日における秀品率(カラーチャート7以上の果皮色)は, はく皮樹で55〜86%と高かったのに対して対照樹は7%で低かった.果皮色, 果皮アントシアニン含量および糖度は, はく皮樹が対照樹よりも有意に高かった.果房重, 果粒重, 遊離酸含量およびβ比には有意差がなかった.これらの結果から, ブドウ'ピオーネ'樹における環状はく皮処理によって, 着色および糖度が向上することが明らかとなり, 夏季に高夜温となる西南暖地における果実品質向上対策としての有効性が示された.

Effects of arm- and trunk-girdling on berry quality traits throughout ripening stage of 'Pione' grapevines exhibiting more vigorous growth were determined. Arm-girdled vine : the differences in berry weight between the girdled and control were not significant; coloring, anthocyanin content, and °Brix were significantly increased by girdling; there were no significant differences in the decrease in free acidity and the increase in β ratio (ratio of tartaric acid to malic acid) between the girdled and control vines. Trunk girdled vines : coloring of the girdled vines was superior to that of the control; per cent of well-colored grapes (a value above 7 on the color chart) among the total production on August 11 was much high on girdled vines and ranged from 55 to 86%, whereas that on control vines was low at 7%; coloring, anthocyanin content and °Brix were significantly increased by girdling; there were no significant differences in cluster weight, berry weight, free acidity, and β ratio between the girdled and control vines. Results demonstrated that the coloring and °Brix of 'Pione' grapevine could be increased by girdling, thereby enabling grape growers to improve the fruit quality produced in the southwest part of Japan which usually has warm-night temperatures in summer.