Variation in flowering within Actinidia chinensis vines

Variation in the time of flowering within vines of two Actinidia chinensis (Planch.) var. chinensis cultivars, 'Hort 16A' and '37-3-18A' ('18A'), is d escribed. The flowering capacity of the two cultivars was very different, w ith 106 terminal flowers and 50 lateral flowers/m(2) of canopy on '18A' vin es compared to only 39 terminal flowers/m(2) on 'Hort16A' vines. However th e variation within vines was similar. The most consistent systematic trend in the time of flowering was within canes, where time of flowering varied b y 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 pr oduced 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 t he cordon, cane size, or type of fruiting wood. On '18A' vines, lateral flo wers formed a separate population, opening 4-5 days after terminal flowers, and should be monitored separately. Any sampling scheme developed from the se data should take account of variation within canes. Vines should be mana ged to reduce variation in flowering date, which has been linked to unwante d variation in fruit maturity at harvest.