Early prediction of harvest fruit size distribution of an apple and pear cultivar

Predictions of fruit sizes for apples were historically based on fruit measurements during normal seasons and average crop loads. These models were inaccurate during years when these conditions were different. A local demand required investigation into the early prediction of the average distribution instead of only average fruit size, at harvest. The relationship between fruit size at 42 days after full bloom (dafb), crop load and fruit size at harvest was calculated for this period. The influence of climate and cultivar led to the development of a specific equation for each cultivar and area. Models for the prediction of final fruit size distribution for 'golden delicious' in Elgin and Ceres, and 'William's Bon Chretien' in Ceres are discussed. A multi-linear regression showed above 80% accuracy for 'golden delicious' and 'William's Bon Chretien' predictions. (C) 2004 Elsevier B.V. All rights reserved.