| パタロブトラゾール処理がラッカセイの乾物分配および葉群構造に及ぼす影響. Effects of Paclobutorazol on Dry Matter Distribution and Canopy Structure in Peanut | |||||||||||||
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| ラッカセイの茎葉の過繁茂を抑制し, 子実への乾物分配を高める目的で, ジベレリン生合成阻害剤であるパクロブトラゾールを用い, 同化産物の各器官への分配割合の変化と, 草型への影響について検討した.供試品種はバージニアタイプ(千葉半立, 千葉43号), スパニッシュタイプ(金時), バレンシアタイプ(バレンシア)およびタイプ間交雑種(ナカテユタカ)の5品種を用いた.莢肥大初期にパクロブトラゾール400ppmを茎葉に処理した.千葉半立, 千葉43号およびナカテユタカはバレンシア, 金時に比べ処理により莢乾物重割合が大きく, 茎乾物重割合が小さく推移した.いずれの品種も処理区では無処理区に比べ節間が小さくなり草高がやや小さくなった.処理により千葉半立, 千葉43号では中層の葉面積が大きくなり, ナカテユタカでは上層の葉面積が大きい逆三角形型の構造を示し, 草型からみると群落内部への光の浸透は悪くなる傾向がみられた.収量構成要素は, 一粒重を除くいずれの形質でも処理区の方が大きい傾向を示した.特に子実数が処理により増加し, 品種別ではナカテユタカで最も子実収量が増加した.また, バレンシアタイプ, スパニッシュタイプよりもバージニアタイプで莢乾物重割合が高められ, 子実収量が増加する効果が認められた.. Five cultivars, including Virginia (Chibahandachi and Chiba 43), Spanish (Kintoki) and Valencia (Valencia) types, and a derivative (Nakateyutaka) from the cross between Virginia and Spanish types, were grown under field conditions. At the early pod growth stage, paclobutorazol, which prevents endogenous gibberellin synthesis, was applied to suppress the growth of the shoot and to improve partitioning of dry matter to pods. Pod dry weight of the treated plants was greater as compared to the control, with smaller stem dry weight. The plant height of the treatment was decreased due to shortening internode length. Leaf area of the treated plants was distributed densely at the upper layers of the canopy as compared to the control, since the leaf area indices were not changed and the internode length was decreased by the treatment. In the yield and yield components except one seed weight, the treated plants were greater than those of the control, although there was no significant difference. Among the five cultivars, Nakateyutaka had the greatest effects of the treatment on pod and seed yield. The Virginia types and the derivative from the cross between Virginia and Spanish types showed large effects of the paclobutorazol treatment in terms of increasing percentages of pod dry weight and pod yield as compared to Spanish and Valencia types. | |||||||||||||
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