ネイハキンカンの着花に及ぼす土壌乾燥処理の影響

Abstract

Effect of water stress on flowering of ‘Meiwa’ kumquat trees (Fortunella crassifolia Swingle) was examined to establish a cultivation system for the first-flush flowers. Water stress was established by withholding water until the soil water content reached 45% for moderate water stress treatment, and 35% for severe water stress treatment. Although three sequential flowerings were observed on the control trees, only one flowering was observed on the water-stressed trees. In the control plot, flowering of the first-flush flowers began on 28 June, and about 10 flowers opened per day. Flowering of the second-flush flowers began on 6 July and the number of flowers opened per day reached 300. In moderate water stress treatment, flowering began on 25 June, and lasted until late July without interruption. Therefore, it was difficult to distinguish between the first- to third-flush flowers. In severe water stress treatment, flowering of the first-flush flowers began on 28 June and the number of flowers opened per day reached more than 200. Water stress did not affect fruit growth or quality of fruit. These results indicate that the number of first-flush flowers increases under water stress after termination of new shoot growth and that the required duration of water stress is about 2 weeks.