四倍体ブドウ7品種の芽の休眠打破に及ぼす低温遭遇量と化学物質の影響(発育制御)  [in Japanese] Effects of Chilling Exposure and Chemicals on Breaking Bud Dormancy in Seven Tetraploid Grape Cultivars(Growth Regulation)  [in Japanese]

ポット植えの四倍体ブドウ7品種を低温遭遇量の異なる3時期(11,1および2月:それぞれの低温遭遇量は73時間.620時間および1,275時間)に剪定した後,直ちに石灰窒素20%水浸出液,5%シアナミドおよび5%二硫化ジアリルを塗布し,20℃以上に加湿したハウスに入れ,休眠打破の効果を比較した.発芽の早さ(発芽所要日数)と揃い(60%発芽所要日数)からみて,休眠打破の効果は低温遭遇量の少ない11月処理で最も大きかったが,化学物質に対する反応性は時期と品種によって異なった.すなわち,シアナミドは11月処理ではほとんどの品種で最も発芽を促し,発芽の揃いもよく,次いで石灰窒素で優れたが,1月と2月処理では両物質にほとんど差がなかった.二硫化ジアリルに対する反応性も品種間で大きく異なり,'安芸クイーン'と'高妻'ではいずれの時期とも,'ピオーネ'では11月と1月処理で発芽を遅らせるか発芽率を低下させた.'藤稔'では,いずれの時期とも化学物質の休眠打破効果に差がなかった.このように,四倍体ブドウの芽の休眠打破に及ぼす効果はシアナミドで最も高く,石沢窒素がこれに次ぎ,二硫化ジアリルで低かったが,これら化学物質に対する反応性は低温遭遇量と品種によって異なった.

Seven potted dormant tetraploid grapevine cultivars grown under forced conditions were treated immediately after pruning with the supernatants of a 20% suspension of CaCN_2, 2% H_2CN_2 and 5% diallyl disulfide in different chilling exposures: late November (73 hours), early January (620 hours) and late February (1,275 hours). The effectiveness of the chemicals in initiating budbreak was assessed by the number of days to initial and 60% budbreak after treatment, indicating the promotion and uniformity of budbreak, respectively. Although the chemicals were most effective when applied in November, there was large variation in the response of buds among cultivars and treatment times. For November treatment, H_2CN_2 was the most effective in accelerating budbreak initiation and enhancing uniformity for almost all cultivars, followed by CaCN_2, whereas in the January and February treatments, there were no differences in the promotion and uniformity of budbreak between the two chemicals. Response of buds to diallyl disulfide varied largely among the cultivars. Diallyl disulfide delayed budbreak initiation or reduced percentage budbreak for 'Aki Queen' and 'Takatsuma' in all the treatment times and for 'Pione' in November and January treatments. For 'Fujiminori,' there was no significant difference in the effectiveness of chemicals on budbreak regardless of treatment time. We conclude that H_2CN_2 is the most effective chemical for budbreak of tetraploid cultivars, followed by CaCN_2, and diallyl disulfide. However, the response of grapevine buds to chemicals varies with the depth of dormancy and cultivar.