Variation in flowering within Actinidia chinensis vines

Abstract

Variation in the time of flowering within vines of two Actinidia chinensis (Planch.) var. chinensis cultivars, 'Hort16A' and '37-3-18A' ('18A'), is described. The flowering capacity of the two cultivars was very different, with 106 terminal flowers and 50 lateral flowers/m2of canopy on '18A' vines compared to only 39 terminal flowers/m2on 'Hort16A' vines. However the variation within vines was similar. The most consistent systematic trend in the time of flowering was within canes, where time of flowering varied by up to 7 days. Shoots near the apex of the cane produced more flowers and they opened earlier than shoots near the cordon. Vines of both cultivars produced a large number of canes near the trunk and few at the end of cordons. However, time of flowering was not consistently affected by position on the cordon, cane size, or type of fruiting wood. On '18A' vines, lateral flowers formed a separate population, opening 4-5 days after terminal flowers, and should be monitored separately. Any sampling scheme developed from these data should take account of variation within canes. Vines should be managed to reduce variation in flowering date, which has been linked to unwanted variation in fruit maturity at harvest.