摘要： 本試驗分別於‘富貴紅’紅龍果芽體分化、花苞長度1 cm，以及開花當天噴施100 ppm氯砒脲（Forchlorfenuron, CPPU），以清水為對照組比較於不同花期階段施用CPPU對其採後果實品質的影響。結果顯示，在花苞長度1 cm及開花當日處理CPPU之果實，採收時其苞片縱徑分別為51.8及54.02 mm，顯著高於對照組之49.0 mm。開花當日施用CPPU後的果實苞片於採收時厚度為2.56 mm，顯著高於對照組之1.79 mm。果實縱徑在開花當日處理者為115.6 mm，顯著大於對照組之109.4 mm。花苞長度1 cm及開花當日施用CPPU之果實較對照組延緩貯藏期間發生苞片黃化8至14天。雖然處理間果實鮮重無顯著性差異，但是在花苞長度1 cm及開花當日施用CPPU者，其果實鮮重皆大於對照組依序為603.8 g、564.5與533.7 g。建議紅肉種紅龍果在開花當日施用100ppm CPPU可在採收時增加苞片厚度且減緩黃化，亦不影響果實硬度、可溶性固形物含量、可滴定酸與貯藏期間果實失重率。The effect of forchlorfenuron (CPPU) on red-fleshed pitaya fruit quality was carried out at different flowering stages i.e., buds, 1 cm flower buds in length, and flowering day. The results showed that CPPU application at 1 cm and flowering day had significant higher longitudinal diameter of the bracts which were 51.8 and 54.02 mm than the control (49.0 mm). The thickness of the bracts treated with CPPU on the flowering day was 2.56 mm significantly higher than the control (1.79 mm). In addition, CPPU application on the flowering day had significantly larger fruit length (115.6 mm) than the control at 109.4 mm. Moreover, CPPU-treated at 1 cm flower buds and on the flowering day significantly delayed bracts yellowing for 8 to 14 days during storage compared to the control. Although there was no significant difference in fruit fresh weight, the fresh weight of CPPU treated at 1 cm bud and on the flowering day were all greater than the control, which were 603.8 g, 564.5 and 533.7 g, respectively. It is suggested that the red-fleshed pitaya treated with 100 ppm CPPU on the flowering day can increase the thickness of the bracts and delay the occurrence of yellowing without affecting fruit hardness, soluble solids, titratable acid and weight loss percentage during storage.