UNDERSTANDING AVOCADO FRUIT SET IN NEW ZEALAND - AN OVERVIEW

SUMMARY Under New Zealand conditions daily temperatures during spring appear to have only a minor role in fruit set. Of most importance has been soil moisture content in the spring of each year with mineral nutrition exerting a general effect on fruit set. Pollination is not a problem area as large numbers of fruit are set but are then dropped in excessive numbers. As yet it is not known what may be setting the crop level from year to year. We have determined that several factors are not important for fruit set but we have only identified one major factor as critical to fruit set. One other factor that may be critical for fruit set according to the scientific literature is carbohydrate reserves (starch) within the tree at flowering. Our research programme over the next few years will concentrate on understanding the role starch levels in the tree play in determining the amount of fruit set for well managed trees with adequate water supply and mineral nutrition.