ブドウ‘マスカット・オブ・アレキサンドリア’に対する潅水制限が樹体の水分，葉温，果実温，果実の全フェノール含量，果皮色に及ぼす影響

　Effects of different deficit irrigation strategies on vine water status, canopy and cluster temperatures, fruit total phenolics, and the color of white table grapes (Vitis vinifera L., cv. Muscat of Alexandria) were compared to a well-irrigated control in 2004 from veraison to harvest at the Okayama University Experimental Vineyard, Japan. The treatments included: (1) well-irrigated control: re-irrigation when the soil moisture tension reached 15 kPa; (2) regulated deficit irrigation (RDI): re-irrigation 4 to 7 days after reaching a soil moisture tension of 15 kPa; (3) fixed partial root-zone wetting (FPRW): one part of the root system was re-irrigated when the soil moisture tension reached 15 kPa; and (4) alternate partial root-zone wetting (APRW): one part of the root system was re-irrigated when the soil moisture tension reached 15 kPa, and every week the irrigated part was switched. As the stress developed in RDI vines, leaf water potential and transpiration rate decreased and canopy and cluster temperatures increased as compared with the control. In contrast, both FPRW and APRW vines had similar leaf water potential and canopy and cluster temperatures, but less leaf transpiration rate as compared with the control. At harvest, fruits from all treatments had higher skin total phenolics and CIELAB a＊ values than the control. RDI fruit had higher total soluble solids (TSS), a similar acidity, and smaller size compared with the control. FPRW and APRW fruits had slightly higher TSS, lower acidity, and a similar size compared with the control.ベレゾーン期から収穫期までの潅水制限処理が‘マスカット・オブ・アレキサンドリア’ブドウ（Vitis vinifera L｡）の水分条件，葉温，果実温，果実の全フェノール，果皮色に及ぼす影響を，十分に潅水した樹と比較した．実験は2004年に岡山大学農学部内の実験圃場で行った．処理区は，１) 土壌水分張力が15kPa に達したときに潅水する対照区，２) 土壌水分張力が15kPa に達してから４～７日後に潅水する制限潅水区，３) 土壌水分張力が15kPa に達したときに根域の半分に潅水する片側潅水区，４) 片側潅水する根域部分を１週間ごとに変更する交互潅水区とした．制限潅水区では水分ストレスが強まるにつれて葉の水ポテンシャルと蒸散速度が対照区よりも低下し，果実温が高くなった．しかし，片側潅水区と交互潅水区では，葉の水ポテンシャルと葉温，果実温は対照区と同程度で，蒸散速度が低下した．収穫期の果皮の全フェノールと CIELAB a＊ 値は，潅水を制限した各区では標準区より高かった．制限潅水区の果実は，標準区より糖度が高く，酸度は低く，果粒は小さかった．片側潅水区，交互潅水区では糖度がやや高く，酸度は低く，果粒の大きさは同程度であった

マスカット・オブ・アレキサンドリア収穫果房の切り分けが果実品質に及ぼす影響

In 2003 and 2004, the potential of using table grapes, cv. Muscat of Alexandria, as fresh-cut products was cvaluated by investigating the effects of postharvest cluster stem excision on several quality attributes. Clusters were harbester either at 17 or 19℃Brix from mature grapevines grown in Okayama, Japan. The treatments included: (1) No excision (C): Intact clusters; (2) Excision at Iaterals (L); Branches carrying 2-7 berries; and (3) Excision at pedicels (P): Single berries without pedicels. Fruit was placed in commercial packages and stored for 6 days 25℃. As regards aroma, linalool production by P increased markedly without major changes in the other monoterpenes. In addition, high geraniol production was observed in C, while minor aroma changes ware observed in L. Total amino acid concentrations increased in P and C in comparison to L. Interestingly, at the end of the experiment, berries of treatment P had the highest firmness and visual quality, followed by C, while L was the lowest. It is concluded that grapes of Muscat of Alexandria are suitable for stemless marketing.マスカット・オブ・アレキサンドリアの果房がカットフルーツとして適するかどうかを，2003年と2004年に検討し た．岡山で生産された完熟した果房を，房全体のまま（果房），穂軸を切り離して２―７果粒の小房に切り分け（切り 房），小果梗で切り離して個々の果粒に切り分け（果粒），の３区とした．これらを箱詰めし，25℃で６日間，保蔵し た．保蔵中の果実の品質変化を分析した結果，主要な香気成分であるリナロールは果粒ごとの区で最も大きく増加し， ゲラニオールの増加は果房のままの区で大きかった．全アミノ酸含量の増加は，切り房区に比べて果粒区と果房区で 大きかった．しかし，果粒区では保蔵後の果粒硬度が最も高く，外観も優れ，次いで果房区，切り房区の順であった． 以上の結果から，マスカット果房を小果梗で切除し，果粒単位の状態で出荷することによって品質を最も高く保つこ とが可能であ