應用園藝技術誘導椪柑形成不時花

Abstract

柑橘類之花芽分化習性與荔枝、龍眼等亞熱帶果樹類似，在秋冬季必須經過適當的低溫、乾燥、短日等環境條件才能形成花芽。本省柑橘遇到長期乾旱之後，若在夏秋季進行適當的肥培管理及灌水，萌發之秋梢會形成少數不時花。因此，擬利用柑橘樹在逆境條件下自然形成不時花之特性，自1991年開始以人為方法處理，觀察應用在調節椪柑產期之可行性。自6月開始在樹幹進行環刻與中耕斷根處理，並控制夏梢生長，在9月及10月間進行修剪、施肥及灌水等處理，調查夏秋梢萌芽後之帶花率。初步試驗結果，6月間環刻處理區之新梢抑制率及花芽率分別達43.4％及133%,8月及10月處理者與對照區比較無差異；6月中耕區之新梢抑制率及修剪後秋梢萌芽率亦很高。10月以後環刻樹幹者傷口癒合緩慢，到11月天氣轉為冷涼後葉片快速黃化，以致在冬季嚴重落葉，翌年之花蕾形成期較對照區早，但直花比例高，著果率低。由試驗結果得知，在6月以環刻或中耕配合修剪及施肥等方法處理，雖具有提高秋梢帶花數的效果，但植株問之差異大，著果率低，無法達到經濟栽培之目標。 This study was conducted to survey the off-season flowering of ‘Ponkan’ and the possibility of regulating production season artificially. The growth of the Summer-flush was retarded by girdling and root-cutting since June, and the induction of Summer-Autumn flushes was followed by pruning, fertilizing and irrigation during September and October. The results showed that girdling at June had better effect on shoot-retardation and off-season flower induction, the treatments in August and latter months had no difference to that of the controls. Root-cutting at June also had better effect on shoot retardation and higher Autumn-flush sprouting rate after pruning. The trunk healing was slower in those girdled after October and the leaves were weakened to fall in the winter, which caused the flowers formed earlier but the fruitsetting was poor. It seemed that the off-season flowering on the Autumn-flushs could be promoted by means of girdling, root-cutting and fertilizing, whereas the huge difference among the trees was difficult to control and the low fruitsetting revealed that the economic production by of fseason flower induction has a long way to go.