蘿蔔空心之研究

Abstract

7 個蘿蔔品種，分5 個播種期，及4 個採收期，以階乘層級設計，進行影響蘿蔔空心因子之試驗，於1978 年4 月中旬開始在本所試種，以測定各品種不同播種期與採收期之空心情形。其結果為採收期對空心程度之影響較播種期大，而播種期又遠較品種間之差異為大。各不同處理空心程度，主要是在於播種後20 日到採收日，亦即根部肥大期之平均氣溫及日夜溫差而定。4 月15 日播種，空心程度較少，8 月15 日次之，中聞三次播種者均極嚴重。品種間對空心程度差異亦極顯著，黑葉美濃早生4 月15 日播種55 天後採收，8 月15 日播種70 天後採收，冬瓜白4 月15 日播種50 天後採收，其空心情形甚少，而青皮蘿蔔不論任何播種期與採收期幾乎無空心情形，故青皮蘿蔔似乎可作夏季蘿蔔品種育種材料。 The purpose of this study was to investigate the occurrence of pithiness of radish roots in the summer. Experiments involving 7 varieties. 5 planting dates and 4 harvest dates were conducted at Taichung, Taiwan from April to August in 1978. It was found that harvest date was the most important factor in causing the pithiness, followed by planting date and varietal difference. The degree of pithiness radish roots was mainly determined by the average temperature and temperature difference between day and night from 20 days after planting to harvest which was the corpalancy period of the growing roots. Radishes planted on April 15 showed the least degree of pithiness followed by those planted on Aug. 15. Maximum pithiness was observed when radish were sowed in May, June and July. Early harvest or short growth duration also tended to reduce pithiness. Cultivar “Green skin” showed almost no pithiness regardless of planting and harvest dates and could be used as breeding material for improving varieties suitable for growing in the summer season.