西瓜產期調節之試驗研究

Abstract

冬季1-2月間西瓜植株開花少之原因，主要為西瓜植株受低溫之影響所致。高屏地區為冬季台灣最暖和之地區，1-2月間一般正當氣候下上午4-6時地上 40cm之本均氣溫15.77°C，寒流來臨時可降至10.79°C，尤其低於15°C之累積時間，一天內可達9.8小時(6-14小時)之久，影響西瓜植株開花頗大。冬季1-2月間寒流來臨時氣溫降低很多，不利於西瓜之生育，如持用輕質白色不織布浮蓋植株略有保溫效果。西瓜植株如行整枝栽培則開花一般延遲，但較集中，有便於人工授粉工作，尤其因低溫期欠蜜蜂活動時。整枝支數愈少早期開花結果較多，支數愈多晚期開花結果較多。如春作低溫期間過長，則不宜摘心整枝，以免開花延遲而失去早期賣好價格之獲利機會。 The low temperatures in January and February can affect the flowering of watermelon plants. Kao-pin area is the warmest area in Taiwan during winter season. Under normalclimate, the average temperature at 4-6 a.m. in January and February is about 15.77°C, and cold currents usually fall to 10.79°C. Especially the accumulated times of 15°C lowertemperatures always reach to 9.8 (6-14) hours long one day, and influence greatly on the flowering of watermelen plants. The light material of white nonwoven fabrics floated on watermelon plants can raise some temperatures when cold currents arrive duriny winter season. The flowering of pruned watermelon plants will be post-poned, and more concentrated for the convenience of hand pollination, especially at the inactivities of honey bees due to the long periods of low temperatures. The fewer vines we pruned, the earlier flowering and fruit-setting we obtained. The more vines, the later flowering and fruit-setting we obtained. The watermelon plants of spring crop with the long periods of low temperatures are unsuitable to be pruned and usually postpone the flowering and lose the advantageous opportunity of higher prices at early stage.