評估荔枝翌年開花所需當年生枝條末段梢成熟之邊際時間點

Estimation of the Putative Marginal Timing for Subsequent Flowering in the Last Flush of Litchi ("Litchi chinensis") Current Shoots

張仁育(Jen-Yu Chang) ； 張宇安(Yu-An Chang) ； 方明義(Ming-Yi Fang) ； 林美莉(Mei-Li Lin) ； 張哲瑋(Jer-Way Chang)

《臺灣園藝》 60卷1期 (2014/03) Pp. 27-39

摘要

荔枝為世界重要亞熱帶果樹之一，但開花狀況不良往往造成其產量波動。荔枝自營養生長相轉換為生殖生長相需要充足的涼溫刺激，涼溫期間未成熟枝梢通常無法成功轉換為花序，因此成熟枝梢是荔枝能否順利花芽分化的關鍵因子；相對地，當枝梢發育進程延遲而錯過某關鍵時刻將不利其花序形成。本研究共標記調查‘玉荷包’、‘台農7號早大荔’、‘台農3號玫瑰紅’等三品種荔枝末段梢發育動態，就標記枝條開花與否追溯各調查時間點枝條成熟情形，試圖將末段梢成熟時機連結枝條後續開花情況，亦觀察‘台農3號玫瑰紅’荔枝枝條延遲成熟對翌年花況及著果影響。結果顯示開花枝條末段梢成熟數量的累積具有一邁入趨平時刻，我們稱之為「假定開花邊際時間點」。2012年在嘉義市‘玉荷包’之「假定開花邊際時間點」為11月20日前後、‘台農7號早大荔’為11月2日前後，雲林古坑‘台農3號玫瑰紅’之「假定開花邊際時間點」為11月9日前後。枝梢延後成熟的‘台農3號玫瑰紅’荔枝有開花率低落且出現二輪花情形，進而造成產量低落。本研究印證成功荔枝生產需掌握秋季末段梢抽出及成熟時機，也提出以「假定開花邊際時間點」作為田間管理評估前揭兩關鍵時刻參考依據。

關鍵字

涼溫需求 ； 抽梢循環 ； 開花比率 ； 花序 ； 二輪花

並列摘要

Production of litchi is often unstable due to the erratic blooming. Adequate cool temperature is required for floral induction in litchi and immature flushes do not flower after cool temperature induction in winter. Apparently, more competent flushes formed before cool induction, more inflorescences could emerge in the following season, and vice versa. In this study, we monitored the developmental stages of the last flushes in 'Yu Her Pau', 'Tainung No. 3, Rose Red', and 'Tainung No. 7, Early Big' litchi. Relationships between the timing of the last flushes to reach maturation and flowering ratio in three litchi cultivars were determined. Effects of differential shoot maturity on flowering and fruiting were also investigated in 'Tainung No. 3, Rose Red'. Most shoots that flowered in subsequent spring were those had reached 'the putative marginal time for flowering (pFMT)'. Results showed that pFMT was ca. 20 November in 'Yu Her Pau', 2 November in 'Tainung No. 7, Early Big' at Chiayi City, and 6 November in 'Tainung No. 3, Rose Red' at Gukeng Township, Yunlin County. Low yield of 'Tainung No. 3, Rose Red' resulted from few mature flushes formed on time, leading to poor flowering ratio and occurrence of the second wave of flowering. This study confirms the role of the maturity of last flushes on flowering in litchi during autumn, and pFMT could be used as the reference for field practices.

並列關鍵字

cool temperature requirement ； cyclic nature of flush development ； flowering ratio ； inflorescence ； the second wave of flowering