Does microclimate under grey hail protection net affect biological and nutritional properties of 'Duke' highbush blueberry (Vaccinium corymbosum L.)?

Abstract

Introduction. We tested whether the microclimate under grey hail protection nets (HPN) had an influence on the phenology, vegetative and reproductive potential, and fruit quality traits of 'Duke' highbush blueberry (Vaccinium corymbosum L.) in two consecutive years (2013, 2014). Materials and methods. Light intensity, air temperature and relative humidity were evaluated together with biological properties (flowering and ripening time, bush height and volume, number of flowers and fruits per bush, fruit set percentage, and yield per bush), and fruit quality including biometrical (fruit weight, index of fruit shape and number of seeds per fruit) and nutritional (soluble solid content SSC, titratable acidity - TA, total anthocyanins content - TACY, total phenolic content - TPC and total antioxidant capacity - TAC) parameters. Results and discussion. In both seasons, light was reduced by 5-20% under HPN, whereas daily maximum temperature was 2.4 degrees C higher in the open field (OF). This caused two days earlier ripening time in OF compared to the HPN. The increased yield per bush under HPN was the result of larger fruit weight. SSC were unaffected by the net in 2013 while in 2014 significantly higher value of SSC was registered under HPN compared to OF. Although apparent differences in TACY and TPC were not observed between the treatments, TAC significantly increased under HPN in 2014. Conclusion. The use of grey HPN could be considered as a suitable alternative for the hail protection of highbush blueberry ensuring an increased fruit production without negative effects on their quality.