依日曆或依果實著色率判斷貯藏用桂柑之採收適期

Selecting Optimum Harvest Date by Calendar or by Fruit Coloration for'Ponkan' Mandarins(Citrus reticulata Blanco) for Storage

連續三年，以兩種採收方式採收之果實進行試驗，第一種採收椪柑的方式是選同一天採收黃、半黃｀綠三種（著色率依次為>=70%•35-65% , <=30%）果實，第二種採收方式是早、中、晚三個日期各相隔6至H天分三次採收半黃的果實·第一種方式採收時，較黃的樘柑糖度較高而綠的糖度較低，第二種方式採收者則採收日期早晚糖度無差異。在15'C貯藏約100天後檢查，第一種方式採收者，黃的椪柑腐爛率顯著高於半黃或綠的樘柑，第二種方式採收者則採收日期與腐爛率無顯著關係。第一種方式採收者綠的樘柑貯藏後仍有糖度略低的趨勢；第二種方式採收者則採收日期與貯藏後糖度無顯著關係。由上結果，依果實著色程度比依日曆日期前後判斷採收適期較為可用，而且可以推膺貯藏用槎柑應在樹上有相當多果實達半黃時開始分次採收；每次採的半黃果供貯藏而黃色果立即銷售·綠色果在樹上逐漸轉色到半黃時再採收。

Selected mature'Ponkan'trees were devided into two groups. Fruits of the first group were harvested on the same day and separated into 3 lots according to percent peel coloration : yellow(迄70% yellow), half-yellow (35-65% yellow), and green(;;:; 30% yellow). Fruits of the second group were harvested at half-yellow stage on 3 different calendar dates with 6-to I I-day intervals. Harvested and sorted fruits were then stored at I 5'C for approximately I 00 days. The experiment was repeated for 3 consecutive years. In the first group, fruits harvested yellow had significantly higher storage decay than those harvested half-yellow or green. Fruits harvested green had slightly lower soluble solids(SS) content even after storage than those harvested yellow or half-yellow. In the second group, harvesting dates did not affect storage decay losses or SS contents of the fruit . Half-yellow'Ponkan' mandarins harvested on earlier dates had higher acidity at harvest than similar fruits harvested on later dates, but such a difference disappeared after storage. Percent peel coloration seemed to be a better maturity index than calendar date for'Ponkan'. It is suggested that 'Ponkan'for storage should be harvested for several times from the same orchard or same tree each year and only those half-yellow fruits are suitable for storage. Fruits which are yellow at harvest unfit for long-term storage; and green fruits should be left on the tree until turning to half-yellow before harvest.