Sex expression in fruiting male vines of kiwifruit

Abstract

In three canes on each of five fruiting male kiwifruit vines (A. deliciosa var. deliciosa (A. Chev) Liang and Ferguson), staminate and bisexual flowers were interspersed, so that staminate, bisexual and mixed inflorescences were found. Further variation in inflorescence composition resulted from the abortion of flower buds prior to anthesis. These two sources of variation, in combination, resulted in 19 inflorescence patterns, which varied substantially in frequency among and within vines. Some tendencies were determined. In particular, most of the inflorescences had retained their terminal flower, whereas just over half had retained one or both primary lateral flowers, and in two-thirds of the inflorescences retaining a terminal flower, this was bisexual. The five vines ranged in bisexual flower frequency from 40% to 70%. Phenotypic Gender (P) estimates are given for each vine, based on the frequencies of staminate and bisexual flowers from three canes per vine. Flower development, lability in sex expression and the use of P estimates as part of a selection index in breeding for hermaphrodite kiwifruit cultivars are discussed.