Cumulative effect of time of hand-thinning on fruit size of Golden Delicious and Granny Smith apples

Abstract

The cumulative effect of time of hand-thinning on fruit size of Golden Delicious and Granny Smith apple trees was studied during seven consecutive seasons for Golden Delicious and four consecutive seasons for Granny Smith. Trees were thinned to single flowers or fruitlets per cluster at full bloom, and 25 days and 50 days from full bloom. Thinning at full bloom improved yields significantly during the seven consecutive seasons in Golden Delicious compared with later thinning dates. Similar results were obtained with Granny Smith except during the first season of the trial. The average fruit size of Golden Delicious fruit thinned at full bloom was improved compared with later thinning dates despite the heavier yield of the early-thinned trees. Time of thinning had no significant effect on fruit size of Granny Smith apples. Income from early-thinned trees was consistently higher than from later-thinned trees.

Keywords:

• Apples
• fruit size
• thinning