2022 Volume 21 Issue 2 Pages 149-156
To develop an effective method to raise apple saplings, we investigated the effect of gibberellin paste on shoot elongation of current-year apple saplings. When 100–200-mg paste containing 2.7% gibberellic acid was applied near the shoot tip 2–3 times after spring grafting to August, shoot elongation of the columnar apple ‘Wijcik’ was promoted under both greenhouse and field conditions. In contrast, shoot elongation of ‘Fuji’ was not promoted by the application schemes under field conditions where shoots grew vigorously, but was promoted in a greenhouse experiment using pot culture where shoot-growing activity was weaker. However, 5-times-application of 100-mg gibberellin paste after sprouting to August significantly increased shoot length compared with non- or 3-times-applied saplings. This effect was consistently confirmed in non-columnar cultivars ‘Fuji’, ‘Shinano Sweet’, and ‘Shinano Gold’ and columnar apples ‘Wijcik’ and Morioka 74. This application also increased lateral shoots of all cultivars except Morioka 74. As a result, we found that 5-times-application of gibberellin paste during the growing season significantly increased shoot elongation of current-year-old apple saplings
