夏季重度遮陰與疏花對紅龍果冬季產期調節之影響

The Effects of Heavy Shading and Flowering Thinning in Summer on Off-season Production in Red Pitaya (Hylocereus sp.)

為穩定紅肉紅龍果秋冬季的產期調節的產量，本詴驗的目的在評估抑制夏季開花與疏花對非開花誘導季節的萌花量之影響。詴驗於屏東縣高樹鄉五郎農場果園進行，參詴植株為7年生‘帝龍’，夏季果實的抑制乃藉由在重度遮陰及持續疏花的方式達成。詴驗結果顯示95%的重度遮陰幾乎可抑制夏季萌花，其萌梢枝條比率達22%；持續疏花植株，使夏季萌花枝率提高至84%，該植株雖未結果，卻未促使新梢萌發。這些枝條經秋冬季暗期中斷處理後，夏季重度遮陰與持續疏花處理者，來花枝率分別是夏季正常結果對照組的2.6與3.3倍。整體詴驗結果顯示抑制植株夏季著果，可有效提高冬季暗期中斷處理的萌花量。長期遮陰為省工的處理，重度遮陰雖有抑制夏季萌花的效果，但冬季產期調節時萌花枝率太低；因此遮陰程度、抑制效果與秋冬季產期調節產量之平衡點，仍有待評估。 For stabilizing the off-season production of red pitaya (Hylocereus sp.), the objective of this study was to evaluate the effect of preventing flowering and flower bud thinning in summer on floral emergence in non-inductive season, i.e. winter. The trials were conducted with 7-year-old 'Ti-Lung' plants in Wu-Lang orchard in Pingtung, southern Taiwan. The inhibition of summer fruiting was achieved by heavy shading (95% shading/S) and continuous floral bud thinning (FT/S). The summer floral bud emergence was almost inhibited by 95% of shading along with 22% of shoots sprouting; whereas, continuous floral bud thinning resulted 84% of shoots emerged floral buds without any sprouting. After application of night-break lighting treatment, 2.6 (95% shading/S+NB/W) and 3.3 (FT/S+NB/W) folds of off-season flowers was resulted compared with the control (CK/S+NB/W). In general, the inhibition of summer fruiting may effectively promote off-season flowering after night-break lighting treatment was concluded. For labor concern, long-term shading was suggested; however, such treatment has to trade winter flowering percentage off in the present study. Therefore, the balance among the degree of shading, the effect on flowering inhibition and the off-season productivity should be further evaluated.