ニホンナシ'ゴールド二十世紀'の間伐樹に対する幼木期の整枝法の違いが乾物生産と器官別の分配に及ぼす影響(栽培管理・作型)  [in Japanese] Effects of Various Training Methods on Dry Matter Production and Assimilate Partitioning of Young Filler Trees of Japanese Pear 'Gold Nijisseiki'(Crop Production & Cropping Type)  [in Japanese]

ニホンナシ'ゴールド二十世紀'間伐樹の幼木期の整枝法のちがいが乾物生産量と器官別の分配に及ぼす影響について比較を行った.永久樹の整枝法は3本主枝とした.また,間伐樹は6つの異なる樹形,すなわち3本主枝,4本主枝,6本主枝,改良二分8本主枝,8本主枝,改良二分12本主枝にそれぞれ整枝した.間伐樹は,8年生まで樹冠の拡大を続けた後,9年生以降,樹冠が縮小され,植え付け10年目の果実生産を最後に伐採された.地上部の乾物生産量は,各器官とも,主枝数の多い区ほど多く,この傾向は果実,葉で顕著であった.乾物生産量の果実への分配率は,主枝数の多い区ほど,高い傾向がみられた.また,葉への分配率は,処理区間の差が明かでなかった.新梢への分配率は,4〜6年生時において,また,旧枝への分配率は6〜8年生時において,それぞれ主枝数の少ない区の方が高い傾向が認められた.葉乾物重当たりの地上部乾物生産量は,処理区間での顕著な差が認められず,葉乾物重当たりの果実乾物重は,主枝数の多い区の方が,高い値で推移した.以上の結果より,主枝数が多い整枝法の樹体ほど,果実の乾物分配が多く,果実生産効率が高く,間伐樹として適することが明らかとなった.

To obtain early and high yield from young trees of the Japanese pear 'Gold Nijisseiki', the effects of different training systems on the dry matter production and distribution of above ground organs was investigated. Permanent trees with 3 scaffolds and filler trees with 6 different tree forms having 3 to 12 scaffolds were compared. The dry matter production of the above ground organ was increased in training systems with larger numbers of scaffolds. The dry matter production of the above ground part was higher in the training systems with larger numbers of scaffolds. This tendency indicated that the assimilate partitioning rate for fruit was higher in training systems with a larger numbers of scaffolds. Higher partitioning rates were shown for training systems with a smaller number of scaffolds in both the shoots on 4 to 6-year-old trees and older wood on 6 to 8-year-old trees. There was no significant difference between plots in the dry matter production above the ground per dry weight of leaves. However, the dry weight of fruit per dry weight of leaves remained higher in the plot with large numbers of scaffolds. Filler trees with larger numbers of scaffolds showed higher rates of assimilate partitioning on dry weight of fruit and higher efficiency of fruit production.