產期調節對臺灣番荔枝與鳳梨釋迦產業之影響

Regulation of Sugar Apple and Atemoya Production Season and its Impact on Industry in Taiwan

Two major ＂Annona＂ fruit crops, sugar apple (＂A. squamosa＂) and atemoya (＂A. squamosa×A. cherimola＂), are produced in Taiwan with cultivated area of 5,736 ha and the annual production of 49,864 t in 2012. Sugar apples were introduced to Taiwan more than 350 years ago, and atemoyas were introduced from Israel in 1965. The flower buds of ＂Annona＂ plants are extra-axillary, sprouting from the opposite site of leaves on the shoots. Most of the flower buds of sugar apple and atemoya plants born on the annual shoots, either solitary or two to five flowers in a cluster. New flowers continue to appear towards the apex of the shoots as flowers mature earlier at the basal portions mature. Temperature and light are the major factors influencing the flowering of sugar apples and atemoyas. Sugar apples are hermaphroditic and protogynous dichogamy, and thus self -pollination is rare and unstable. Specific beetles can help natural pollinations. However, poor fruit production and fruit deformation often occurs. Artificial pollination techniques were developed to increase the fruit setting, yields and fruit quality. A ＂two-harvests per year＂ forcing culture model has been developed for producing the sugar apple fruits. By adequate pruning together with defoliation techniques, on-season or even off-season flowering and fruit setting were achieved. A prolonged lighting technology was developed to for almost year round fruit production of sugar apple. Due to excessive rapid growth and water uptake in fruit developmental period, high percentage of fruit cracking after harvest reduced atemoya fruits value in summer months. Using forcing culture, the harvest time of atemoya fruits was regulated from summer to winter-spring with high values. The fruit cracking problem was also solved. The atemoya fruit industry has become more important in Taiwan. Most of the atemoya fruits (99%) produced in Taiwan are exported to China, with up to 8,897 t in 2013, Taiwan has become an important country for atemoya production in the world. 目前臺灣番荔枝屬（＂Annona＂）果樹栽培面積5,736公頃，2012年產量49,864公噸，主要經濟栽培的種類有番荔枝（＂A.squamosa＂）及鳳梨釋迦（＂A.squamosa×A.cherimola＂）二大類。番荔枝引進臺灣栽培已超過350年歷史；鳳梨釋迦則係1965年自以色列引進。番荔枝屬植物之花芽為一種額外腋芽，著生在葉片相對的位置上，新梢萌發後，花蕾即伴隨長出。花蕾通常著生於當年生之小條枝上，有的為單花，有的則是2至5朵叢生。同一枝條各葉節上會陸續開花，開花順序由基部向頂端推進。光及溫度為影響番荔枝果樹開花之主要因子。番荔枝花朵為兩性花且具雌蕊先熟特性，甲蟲為主要授粉昆蟲，惟自花授粉困難且成功率不穩定。利用人工授粉可提高著果率，穩定產量及提高品質。臺灣番荔枝果樹產業已發展出一年二收的栽培模式，依番荔枝開花生理特性，運用修剪枝條加上除葉技術，可促使枝條萌發花蕾進而著果，達到調控產期的目的。近年開發夜間燈照技術，進一步延長番荔枝產期，幾乎達到週年生產程度，僅在5、6月產量較少。鳳梨釋迦方面，自然結果之夏期果採收後容易裂果，不具商業價值，經引入番荔枝產期調節技術後，將產期成功地轉移到低溫月份，冬期果即不會開裂。裂果問題獲得解決後，產業乃蓬勃發展，成為一個重要的果樹產業。臺灣所生產的鳳梨釋迦果實以外銷為主，99%的果實外銷到中國大陸，採收期集中於12月至翌年4月間，2013年外銷量達8,897公噸，已成為世界上重要之生產及出口國。