Table 5 Influence of constant and changing temperatures on shoot structure and flowering of apple trees as assessed by out-door performance in the subsequent spring following overwintering in a cold store at 1 °C (2017 experiment)
From: Temperature control of shoot growth and floral initiation in apple (Malus × domestica Borkh.)
Temperature (℃) | Flowering nodes (%) | Vegetative nodes (%) | Non-breaking nodes (%) | Nodes per tree | Flower cluster per tree | Flowers per tree |
|---|---|---|---|---|---|---|
12 °C cont. | 5.6 da | 75.2 a | 18.8 b | 181.0 c | 9.0 c | 25.8 b |
18 °C cont. | 49.3 a | 24.2 d | 26.4 ab | 225.2 bc | 97.8 ab | 381.0 a |
24 °C cont. | 33.7 ab | 27.2 d | 39.1 ab | 367.8 a | 128.0 a | 375.0 a |
27 °C cont. | 11.0 cd | 42.7 cd | 46.3 a | 399.6 a | 43.2 bc | 115.2 b |
12⟶24 °C | 14.8 bcd | 56.9 abc | 28.3 ab | 209.8 bc | 34.8 bc | 105.8 b |
18⟶27 °C | 17.6 bcd | 45.3 bcd | 37.0 ab | 290.3 abc | 45.3 bc | 152.5 b |
24⟶12 °C | 21.1 bcd | 48.4 bcd | 30.6 ab | 264.5 abc | 48.5 bc | 176.5 ab |
27⟶18 °C | 30.3 abc | 29.3 d | 40.4 ab | 355.8 ab | 97.8 ab | 376.5 a |
Ambient | 9.5 cd | 68.2 ab | 22.3 ab | 219.0 bc | 19.5 c | 66.5 b |
Mean | 21.8 | 46.0 | 32.2 | 280.6 | 59.3 | 199.9 |
P-value | < 0.001 | < 0.001 | 0.03 | < 0.001 | < 0.001 | < 0.001 |