修剪對荔枝生長及產量之影響Ⅰ．對不同生長勢品種新梢生長及開花之影響

Effect of Pruning on the Growth and Yield of LitchiⅠ. Effect of Harvest Pruning on the Flushing and Flowering in Varieties of Different Vigor

採收後修剪對荔枝不同生長勢品種之新梢生長及次年抽穗開花均有顯著影響，生長勢強之玉荷苞及沙坑種於修剪後可立刻抽新梢，其抽梢率達95%，生長勢弱之港尾種抽梢率只有74%，玉荷苞及沙坑種之每枝新梢數及新梢生長均較港尾種為佳，三個品種修剪後發出之新梢均可能於次年抽穗開花，但其抽穗率因品種而有不同，依次為玉荷苞（86.8%），港尾（62.8%）及沙坑（26.3%）。玉荷苞及港尾種修剪與未修剪枝條之抽穗率相近，但修剪後沙坑種抽穗率顯著減少。三品種修剪後之花穗均小於未修剪枝條者。本試驗結果顯示修剪對不同生長勢品種之新梢生長與抽穗開花有不同之反應，未來有可能經由修剪以控制株高度並改進栽培管理。

The effect of harvest pruning on the growth and flowering of litchi (Litchi chinensis, Sonn.) was studied. The responses of flush growth and flowering were significantly different in various-vigor litchi varieties. Ninety-five percent of pruning shoots were flushed in vigorous varieties Yu Her Pan (an upright type) and Sah Kang (a compact type) as compared to only 74% in less vigorous variety Kang Wei. The number of flush per pruned shoot and growth of flush (expressed no average length and diameter) were better in vigorous varieties Yu Her Pan and Sah Kang than in less vigorous variety Kang Wei. The flush grown from pruned shoot were capable of developing panicles next year, and the percentage of flowering of Yu Her Pau, Sah Keng and Kang Wei were 86.8%, 26.3% and 62.8% respectively. The percentage of flowering were not significantly different between pruned and unpruned shoot either in vigorous Yu Her Pan or in less vigorous Kang Wei, while significant reduction of flowering in pruned shoots were found in vigorous Sah Kang. The panicle size of pruned shoots is smaller than unpruned shoots in these three varieties studied, The result indicated that there were significantly different influence of pruning on the flush growth and flowering among vigorous and less vigorous vqrieties. It also showed that the feasibility to control the plant height and canopy and the improvement of management of litchi through pruning.