Export kiwifruit - when size matters
The more kiwifruit on a Hort16A vine the smaller the fruit - but how much smaller may depend on where the plant is grown. HortResearch scientists Annette Richardson, Kevin Patterson and Philip Martin have recently completed a preliminary investigation of the relationship between fruit number and fruit size on Hort16A vines, which was funded by KNZ.
Crop loading relationship on Hort16A vines were developed from data from two seasons in Kerikeri and three seasons in the Bay of Plenty. Mean fruit weight decreased linearly as fruit numbers increased. However the relationship between crop load and final fruit size on the new golden kiwifruit was considerably different on vines in Kerikeri and those in the Bay of Plenty. The Bay lived up to its name, with a decrease in average fruit weight of only 2.4g when fruit numbers were increased by 10fruit/m2 of canopy, compared to a decrease of 5.5g for a similar increase in crop load on vines in Kerikeri.
As growers look for premium, export quality fruit, information such as this is vital for vine management. From this preliminary evaluation of crop loading on Hort16A vines it is recommended that growers in the Bay of Plenty aim to harvest around 40 fruit/m2 of orchard canopy area, to produce fruit with a mean weight of 100g or larger. In Kerikeri, a crop load of around 35 fruit/m2 should give a mean fruit weight of around 100g on well-managed vines.
Further investigations are now needed to confirm this important result, as well as to examine the sustainability of high crop loads and their effects on fruit maturity and colour.