| 摘要： ‘大紅’紅龍果(Hylocerus. polyrhizus ‘Da Hong’)為台灣主要之栽培及外銷品種，具自交親和性，然夏季高溫(35-40℃以上)下常有結果不良及小形果之產業問題，初步已知是雄蕊花粉異常所致。本研究以南投縣草屯鎮之7年生16目網室栽培之植株為材料，於民國107年及108年5-9月間分別進行，107年以簡易遮陰降溫資材配置、非高溫逆境下大紅有效花粉之蒐集與儲存及人工授粉非高溫逆境及擬高溫逆境之花粉，108年以異質花粉(‘富貴紅’)進行蒐集與儲存、以不同溫度培養之異質花粉人工授粉及前年度遮陰等處理，探討未遮陰+自花授粉處理(對照組)、遮陰+自花授粉處理、未遮陰＋非高溫逆境之花粉處理、未遮陰＋高溫逆境之花粉處理及泰維克套袋處理對果實產量、品質之影響。 107年試驗結果顯示，‘大紅’紅龍果新鮮花粉活力(花朵開放當天)經於25℃、修正BK培養基培養20小時後之萌芽率最高(15% sucrose萌發率61.7±9.8%，20% sucrose萌發率44.8±11.8%)；‘大紅’紅龍果新鮮花粉無抽氣處理者以4℃保存之花粉壽命較佳，至第9天完全失去花粉活力；新鮮花粉經抽氣處理者以抽氣1小時後貯藏於4℃下較佳的保存條件，花粉活力由1天後的30.2±10.8%至12天後失活。 因試驗期間遇雨季，田間並未有典型高溫產生，因此改以35℃培養花粉供田間授粉處理。在對照組、遮陰、非高溫逆境授粉、35℃及泰維克袋處理下結果率並無差異，但以35℃培養後進行人工授粉之果實顯著低於其他處理(僅142g重)。也因此得知‘大紅’紅龍果在35℃的環境下其花粉會遭受不可逆之傷害，而導致果實小果化。遮陰處理下其果實大小於對照組並無差異。 108年之試驗結果顯示，‘富貴紅’紅龍果0天新鮮花粉活力(花朵開放當天)經於30℃、20%修正BK培養基培養12小時後之萌芽率最高(15% sucrose萌發率52.7±5.6%，20% sucrose萌發率55.9±4.1%、25% sucrose萌發率42.2±8.6%)，且發現‘富貴紅’紅龍果花粉在高溫下培養仍較前一年度‘大紅’紅龍果花粉有更佳的萌芽率。由此可知，‘富貴紅’紅龍果是一耐高溫之品種；‘富貴紅’紅龍果新鮮花粉經抽氣處理者在抽氣1小時、2小時及3小時後貯藏於4℃下較佳的保存條件，花粉活力在貯藏2天後仍有72.4±2.5%、75.8±4.2%及81.2±4.2%，至7天後失活。 人工授粉試驗係將‘富貴紅’紅龍果之新鮮花粉分別至於25、30、35、40℃進行花粉培養後方進行授粉。結果顯示，在田間溫度高於35℃時‘大紅’紅龍果果實有較小的現象，而利用遮陰及‘富貴紅’紅龍果花粉進行授粉之果實可減緩此現象，其中以‘富貴紅’紅龍果花粉授粉效果最佳。因此綜合兩年之試驗可知，在高溫環境下利用遮陰網進行遮陰或以耐高溫之品種花粉進行授粉，可以減緩高溫‘大紅’紅龍果小果化之現象。 ‘佛利蒙’柑(Citrus clementina x Citrus reticulata)是以小果種寬皮柑(‘Clementine’)與椪柑雜交選育成的早熟柑橘，具有耐病害的特性，雖樹形小但卻容易結果且豐產，結果穩定。果實成熟時為亮麗的橙紅色，果形呈扁圓形，果皮 薄且易剝，果實汁多、糖度高、酸度中等，並保有‘Clementine’之風味。然在採收初期多為半轉色果，賣相不佳，但此時應供不應求故價格較高，隨著產量的增加北部地區進行採收時往往是供過於求的時期而導致價格低迷，因此希望藉由催色處理使北部‘佛利蒙’柑能提早轉色，並供應初期的消費需求。 以苗栗卓蘭吳氏7年生之佛利蒙柑果園為材料，於107及108年分別進行催色處理，107年以不同轉色程度分為轉色前及1/3轉色後搭配不同濃度之益收生長素(50、100、200 ppm)，以轉色前為噴施益收生長素為對照組，調查果實催色、果實品質、開花時間及價格之影響；108年於轉色前噴施200、400、600 ppm進行催色並以轉色前為噴施益收生長素為對照組，調查果實催色、果實品質、落葉率及隔年開花時間。 107年結果顯示，轉色前施用200ppm果實之a*值於第3週開始與對照組有差異，並於後續快速上升，且較其他處理早達商業價值(轉色前噴施200ppm於10/20 採收，其他處理於11/4)，但果實可溶性固形物(TSS)卻顯著低於對照組處理(轉色前噴施200ppm：10.0±0.3; 對照組：11.8±0.3)，但在價格方面，轉色前施用200ppm 益收生長素採收時批發價格(44.2元/公斤)高於其他處理所採收的價格(36.3元/公斤)，而所有處理皆於108年2月4日開花。 108年結果顯示，以更高濃度(600及400 ppm)的益收生長素雖然可以提早採收(600 ppm: 10/15; 400ppm: 10/22; 200 ppm: 10/28; CK: 11/14)，但卻對植株造成影響，在處理過程中以600、400ppm的植株有顯著的落葉，落葉率達70~77%，在果實品質上施用益收生長素的處理果實縱徑都顯著較小(52~55 mm)，且以高濃度(600及400 ppm)的益收生長素處理其果實可溶性固形物(TSS)分別為11.1 ± 0.1及11.0 ± 0.3顯著較低，並於隔年較晚開花(CK及200ppm於2/29盛花；400ppm及600ppm於3/14)。 綜合上述得知，於轉色前以200ppm益收催色在‘佛利蒙’柑是具可行性的，可使北部‘佛利蒙’柑提早成熟轉色，而施以高濃度之益收生長素雖會使果實更早轉色，但會使植株落葉，因此在施用上仍需注意樹勢及施用倍數。‘Da Hong’ pitaya (Hylocerus polyrhizus) is self-compatible and produces a high yield. However, it generally produces miniaturized fruit during summer months in Taiwan; currently, the reason behind this miniaturization is not recognized. This study aimed to determine whether high temperature affects mature fruit size in the field using 7-year-old plants grown in a net house between May and September of two consecutive years (2018 and 2019) in Caotun, Nantou, Taiwan. The study in 2018 consisted of three parts: 1) an in vitro fresh pollen test assessing the following treatments with different sucrose concentration, 2) storage of ‘Da Hong’ pollen with and without vacuum pumping and freeze drying, and 3) determination of whether high temperature affects mature fruit size in the field with and without shading, pollination and bagging. The 2019 phase consisted of the same test using heterogeneous pollen (‘Fu Gui Hong’). The result show that ‘Da Hong’ pollen displayed the highest level of in vitro germination activity when incubated at 25℃ using BK solution media with a 15% sucrose concentration. The tube lengths of pollen incubated using BK solution with 15% sucrose concentration at 25, 30, 35, and 40℃ were all longer than that of pollen incubated using the same solution with a 20% sucrose concentration. Results demonstrated that the optimal pollen storage method is 1 hour of vacuum pumping at 4℃; the resultant pollen was still viable after 1 day of storage. For artificial field pollination, pollen was incubated at 35℃. The fruit set was consistent under all treatments. There were no marked differences in traits between self-pollinated fruits and those pollinated with non-stressed pollen, regardless of shading status. However, the weights, seed numbers, and seed weights were significantly reduced in the fruits pollinated with heat-stressed pollen and no shading. Pollination with non-heat-stressed pollen and shading to reduce heat stress may be beneficial for improving fruit development in high temperatures under field conditions. Additionally, in vitro germination of ‘Fu Gui Hong’ pollen yielded the highest activity when incubated at 30℃ using BK solution with a 20% sucrose concentration (germination with 15% sucrose: 52.7±5.6%; with 20% sucrose: 55.9±4.1%; with 25% sucrose: 42.2±8.6%).Because ‘Fu Gui Hong’ pitaya pollen incubated at a high temperature still germinated at a higher rate than ‘Da Hong’ pitaya pollen, we can deduce that ‘Fu Gui Hong’ is a eat-tolerant variety. Among all treatments, in vitro incubation at 30℃ using BK solution with a 15%sucrose concentration yielded the longest pollen tube length. In terms of storage, fresh pollen and pollen after 1 hour of vacuum pumping at 4℃ remained the most viable. However, activity was more stable in the first 3 days in pollen stored by vacuum pumping for 2 hours at 4℃. The net house’s ambient temperature exceeded 35℃; shading reduced light radiation, light intensity, stem temperature, and maximum daily temperature but did not affect the average daily temperature. There were no significant differences among traits of fruits pollinated by ‘Fu Gui Hong’ pollen incubated at 25, 30, 35, and 40℃ before pollination. However, self-pollinated fruit under non-shaded conditions showed a remarkable reduction in weight, seed number, and seed weight; despite this, there were no significant differences in the peel color or the sugar content of the flesh among all treatments. We concluded that high temperatures lead to fruit miniaturization in ‘Da Hong’ pitaya. Furthermore, shading and pollination with heat-tolerant pollen may be beneficial for improving fruit development in high temperatures under field conditions. ‘Fremont’ (Citrus clementina x Citrus reticulata) is a disease-tolerant, early-harvest mandarin tree. Although ‘Fremont’ trees are small, they yield high fruit sets and high production. The fruits’ peel color begins poorly but transforms to a bright orange upon maturity. This study aimed to determine the feasibility of using ethephon for the degreening of ‘Fremont’ fruit in the field. The study was divided into two parts: 1) using low concentrations of ethephon at different color phases (control treatment, or no ethephon; 50, 100, and 200 ppm ethephon before color transformation; and 50, 100, and 200 ppm ethephon after 1/3 color transformation), and 2) using higher concentrations of ethephon (control treatment and 200, 400, and 600 ppm ethephon before color transformation). The results showed that the a* values of the fruits differed at the beginning of the third week between the control group and the group that received 200 ppm ethephon before color transformation and rapidly increased in the follow-up. Fruits from this group also reached commercial value earlier than the fruits from other treatment groups, but their total soluble solids (TSS) content was significantly lower than that of the control group. Fruit treated with higher concentrations of ethephon (400 and 600 ppm) could be harvested earlier, but their TSS content was significantly lower than those of fruits from other treatments. Additionally, these plants demonstrated significant leaf drops (70-77%). And their flower blooms occurred later in the following year. |
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