Characteristics of flower bud differentiation in highbush blueberry (Vaccinium corymbosum L.) cultivars.

摘要

The characteristics of flower bud differentiation in 8 highbush blueberry (Vaccinium corymbosum) cultivars, i.e. Bluecrop, Bluejay, Dixi, Jersey, Rancocas, Sharpblue, Spartan and Sunrise, were investigated. The blueberry buds burst from late March to mid-April in Iksan, Korea Republic. The buds of Sharpblue (Southern-type), swelled on 23 March, while those of Jersey and Sunrise on 13 April. Their blooming in Iksan started from mid-April to late May. Sharpblue and Jersey were the earliest (16 April) and the latest (25 April) blooming cultivars, respectively. Shoot resting dates of the cultivars, as estimated by the apical bud wilting and tip blackening, ranged from early May to mid-July. Since the axillary buds enlarged and took the form of terminal buds, they were regarded as pseudoterminal buds. The flower buds were not changed morphologically until late August, but subsequently became larger and developed numerous florets. Thus, the flower bud differentiation was thought to occur late August. Flower buds were formed at the second or third node from the apical bud. The number of flower buds on short length shoot and shoot of 10-30 cm length was from 1 to 2 and from 2 to 3, respectively. The number of florets per flower bud ranged from 6.8 to 11.0 and Bluecrop and Dixi were very large in coefficients of variation..