The influence of canopy management on visible-near infrared spectral properties of kiwifruit berries

Canopy density may affect the storage properties and economic value of kiwifruit. Berries grown under dense canopy conditions (LAI>3) may be more prone to storage disorders than berries grown under open canopies (LAI<3). This study investigates the influence of canopy management treatments on the visible-near infrared (VNIR) spectral properties of kiwifruit berries at harvest. Summer pruning was used to create two canopy treatments, open or dense, that were applied to whole canopies of 24 mature kiwifruit vines. At harvest maturity, a representative sample of berries from each vine was collected. VNIR spectral data, soluble solids degrees Brix, (1997 only), fresh and dry weight were measured from 1188 berries in 1997 and 762 berries in 1998. Hartley transformation and canonical analysis were used to reduce the absorbance VNIR spectra to a single canonical variate score for each berry. Berry properties and the VNIR canonical score were analysed by ANOVA. Canopy treatment had a significant effect on the VNIR canonical score in both seasons, and on fruit weight in 1998, but not on individual berry weight, dry matter % or soluble solids at harvest. Although canopy treatment did not consistently affect conventional maturity parameters, the influence of canopy density on berry spectral properties suggests that VNIR data has potential to characterise fruit lines grown under different canopy conditions.