Rain Cover and Netting Materials Differentially Affect Fruit Yield and Quality Traits in Two Highbush Blueberry Cultivars by Changes in Sunlight and Temperature Conditions

Abstract

The use of covers to protect blueberry orchards from adverse weather events has increased due to the variability in climate patterns, but the effects of rain cover and netting materials on yield and fruit quality have not been studied yet. This research evaluated the simultaneous effect of LDPE plastic cover, woven cover and netting materials on environmental components (UV light, PAR, NIR and growing degree days, GDD), plant performance (light interception, leaf area index, LAI, yield and flower development), and fruit quality traits (firmness, total soluble solids and acidity) in two blueberry cultivars. On average, UV transmission under netting was 11% and 43% higher compared to that under woven and LDPE plastic covers, while NIR was 8 -13% higher with both types of rain covers, with an increase in fruit air temperature and GDD. Yield was 27% higher under woven cover with respect to netting, but fruit firmness values under netting were 12% higher than those of LDPE plastic cover. Light interception, LAI and flower development explained 64% (p=0.0052) of the yield variation due to the cover material effect. The obtained results suggest that the type of cover differentially affects yield and fruit quality in blueberries due to the specific light and temperature conditions generated under these materials.