A Crop Estimation Technique for Highbush Blueberries

Abstract

This report describes our attempts to develop yield prediction methods for ‘Bluecrop’ and ‘Jersey’ highbush blueberries. Considerable variability was observed across years in number of flower buds per shoot, fruit set, individual fruit weight, cane diameter and number of laterals per cane. However, there was a significant association between the weight of green fruit at the second stage of development and ripe fruit weight at harvest. Among five different sampling strategies, tedious counting of all the fruit in individual bushes was most tightly correlated with individual bush yields, but the quickest estimate, based on counting the number of fruit within a 625 cm ²surface (hoop counts), was also significantly associated. Hoop counts were used to estimate yields on growers fields when the bushes were at bloom, the fruit were in stage II of development, and 30% of the fruit were ripe. The estimates made at the stage II and 30% ripe stages were significantly associated with actual yields, but were 15-40% high depending on developmental stage and cultivar.