|關鍵字： 紅龍果；肉質莖營養；花芽誘導；抗莖潰瘍病品系；Pitaya；Mineral elements in cladodes；Floral bud induction；Canker disease-resistance lines
|摘要： 近來，紅龍果栽培面積日益增加，因此連帶產生的問題也就隨之而增加。紅龍果在栽培生產上常面臨施肥標準不一、電照效果不穩定以及莖潰瘍病菌的肆虐，因而造成施肥過量、過多能源浪費以及廢園等後續問題。因此，本論文藉由探討紅龍果肉質莖養份的變化，進而提供後續合理化施肥制訂應用。此外，本論文也希望開發另一種產期調節之方法，以減少過量電照造成的能源浪費。同時，本論文也篩選市面所收集到的部分品系，並希望可以從中篩選出較抗病之品系，以作為將來育種上之應用。 1月、3月以及7月份紅龍果肉質莖無機養分調查結果，以當季肉質莖中養分變化較大，其中以氮、磷、鈣與鐵濃度呈下降之現象，而鉀、鎂、錳、鋅與銅濃度則呈現上升之現象。相較與當季與非當季肉質莖中無機養分變化較為平緩。但兩者之變化趨勢是相似的，唯有非當季肉質莖中鎂與錳濃度之變化是與當季肉質莖不同。紅龍果肉質莖中無機養分之增加幅度將因地區而有所差異。此外，當季肉質莖中含大量鉀元素，而非當季肉質莖中含大量鈣元素。在受測樣本中，紅龍果肉質莖養分濃度之變化與土壤養分狀態無正相關，而會因品種而有所差異。紅龍果當季肉質莖中含氮0.99~1.48%、磷0.15~0.32%、鉀2.64~4.69%、鈣0.71~1.99%、鎂0.37~0.80%、鐵11~32ppm、錳8~37ppm、鋅20~38ppm與銅0.3~7ppm。非當季肉質莖中含氮0.78~1.11%、磷0.19~0.58%、鉀0.92~3.05%、鈣2.49~6.01%、鎂0.43~1.08%、鐵8~28ppm、錳18~65ppm、鋅30~40ppm與銅0.1~4ppm。 越南植物生長調節劑（VSL 1）最佳處理時機為6月與7月，這兩月份於當季肉質莖中花芽誘導率分別為20%以及22%，而在非當季肉質莖中則為9%以及20%。於11月份至隔年5月份，此藥劑均無法誘導花芽之萌生。藥劑處理後3天即可見花芽之萌生。藥劑誘導之果實在果重、果長、可溶性固形物含量、酸度、果皮厚度與果實萼片數測定結果均與正常產季之果實無顯著差異。此外，福芬素（CPPU）與激勃素（GA3）組合藥劑或單獨福芬素處理也具有誘導紅龍果花芽萌生之效果，但各組合中均會誘導果實基柄伸長3.55~6.7cm。其餘之果實品質測定如果重、果長、果寬、可溶性固形物、酸度、果皮厚度、萼片數與果實硬度均與正常產季之果實相似。 紅龍果莖潰瘍病之抗病品系篩選結果以無刺與澎湖紅肉品系抗病性最佳。初試驗中，無刺與澎湖紅肉品系在病原菌接種28天後，其當季肉質莖之發病率為3.85%與7.69%，而在非當季肉質莖之發病率則為0%以及3.85%。宜蘭紅肉品系在接種後21天，其發病率已達80%以上，因此視為不抗病品系。重複試驗中，無刺品系在接種後21天時之發病率只有11.11%，而不抗病品系宜蘭紅肉之發病率則為95.56%。在肉質莖成熟度對莖潰瘍抗病反應結果中，發現所有年齡之肉質莖均會感病，其中以生長一週之肉質莖發病率最嚴重，於病原菌接種後7天其發病率達84.45%，接種後21天發病率更達100%。生長一個月並成熟與生長三週之肉質莖對莖潰瘍病菌有較高的抗性，在接種後21天，兩者之發病率分別為40%與36.67%。In recent years, the production area of pitaya incresed gradually, therefore new problems also arised. Pitaya production may face problems such as nonstandard fertilization, unstable lighting and severe stem canker disease which in turn resulted in excessive fertilization, overuse of energy and discarding of orchard. In this study, we investigated the variation of mineral elements in pitaya cladodes, to provide a reasonable fertilizer application method and to develop a new forcing culture method aiming to reduce energy waste. Meanwhile, some pitaya lines were collected from local market to screen for disease-resistance which can be applied in future breeding program. Pitaya cladode mineral composition was investigated in January, March and July, we found that the mineral composition of young pitaya cladodes showed large variations, compared to old pitaya cladodes. Nitrogen, phosphorus, calcium and iron concentration decreased, but potassium, magnesium, manganese, zinc and copper concentration increased. Changes of mineral composition in old pitaya cladodes were smaller, compared to young pitaya cladodes. Variation pattern of mineral composition in two different ages of pitaya were the same , but changes of magnesium and manganese contents were found to be different in young pitaya cladodes compared to old pitaya cladodes. Mineral composition of pitaya cladodes may vary from place to place. In adition, young pitaya cladodes have high potassium content and old pitaya cladodes have high calcium content. Mineral composition of pitaya cladodes was not correlated to mineral composition of soil but may vary in different variaties.Young pitaya cladodes contained 0.99~1.48% nitrogen, 0.15~0.32% phosphorus, 2.64~4.69% potassium, 0.71~1.99% calcium, 0.37~0.80% magnesium, 11~32ppm iron, 8~37ppm manganese, 20~38ppm zinc, and 0.3~7ppm copper. In contrast, old pitaya cladodes contained 0.78~1.11% nitrogen, 0.19~0.58% phosphorus, 0.92~3.05% potassium, 2.49~6.01% calcium, 0.43~1.08% magnesium, 8~28ppm iron, 18~65ppm manganese, 30~40ppm zinc, and 0.1~4ppm copper. The best timing to treat Vietnam plant growth regulator VSL 1 was in June and July. Application of VSL 1 in June and July can achieve 20% and 22% of floral induction rate in young pitaya cladode and 9% and 20% in old pitaya cladode, respectively. VSL 1 treatment was unable to induce floral induction in pitaya if treated during the period from November to the next May. Flower bud formation was visible three days after VSL 1 treatment. In addition, fruit quality after treatment with VSL 1 was not significantly defferent from the normal season fruit in terms of fruit weight, fruit length, number of sepals, peel thickness, total soluble solids content and titratable acidity. All CPPU and GA3 mix solutions can induce flower bud formation and 3.55~6.7cm long stalk formation. Furthermore, fruit qualities such as fruit weight, fruit length, fruit width, number of sepals, peel thickness, total soluble solids content, titratable acidity and firmness were similar to normal season fruit after application of CPPU and GA3 mixed solution. Results from pitaya stem canker disease-resistant line selection indicated that stingless and Penghu red pitaya lines were the best candidates. During our initial disease-resistant test, stingless and Penghu red pitaya line showed 3.85% and 7.69% of canker incidence in young pitaya cladode 28 days after inoculation and 0% and 3.85% of canker incidence in old pitaya cladode, respectively. Twenty one days after Neosyctalidium dimidiatum inoculation, Yilan red pitaya line showed at least 80% of canker incidence indicating that Yilan red pitaya line was not resistant to pitaya stem canker. Result from our second test demonstrated that stingless pitaya line had 11.11% of canker incidence 21 days after Neosyctalidium dimidiatum inoculaton. In contrast, Yilan red pitaya line had 95.56% of canker incidence. Our results also suggested that all ages of pitaya cladodes can be infected by Neosyctalidium dimidiatum with 1-week-old pitaya cladode being the most volunerable which had 84.45% of canker incidence 7 days after Neosyctalidium dimidiatum inoculation and 100% of canker incidence 21 days after inoculation. One-month-old (maturity) and 3-month-old pitaya cladodes were more resistant to stem canker disease which showed 40% and 36.67% of canker incidence 21days after Neosyctalidium dimidiatum inoculation, respectively.