REFLECTIVE FABRIC IMPROVES INTRA-CANOPY LIGHT LEVELS AND INCREASES YIELD IN A LOW-DENSITY, MATURE 'D'ANJOU' PEAR ORCHARD

Abstract

Reflective fabric was installed spring 2009 in a mature, low-density ‘d’Anjou’ pear orchard (269 trees ha-1) to investigate its influence on canopy light environment, fruit size, yield and postharvest fruit quality. Four treatments were studied: 1) no Fabric (NF), 2) fabric applied prior to full bloom (FB) and removed 75 days after full bloom (DAFB) (F-75), 3) full-season fabric applied prior to FB and removed at harvest (F-FS), and 4) shade, 60% shade-cloth applied 60 DAFB through harvest. Weekly fruit growth rate and average fruit size at harvest were not affected by fabric treatments. Shaded fruit were markedly smaller. Total tree yield was significantly greater for fabric treatments relative to the control (c.a., 20%), but not significantly different between fabric treatments, indicating that increased tree yields were due to an increase in fruit number, occurring between FB and 75 DAFB. Higher yields were observed for fabric treatments in the lower exterior, mid and interior canopy. Photosynthetic active radiation (PAR) was increased under fabric by 25, 90 and 30% in the exterior, mid and interior zones of the canopy, respectively. Measurement of reflected PAR from fabric was approximately15% of the total light incident on the canopy exterior, as opposed to approximately 2% over the grassed alleyways of NF. At harvest, firmness of exterior-canopy fruit was 64.7, 64.4 and 67.2 N for F-FS, shade and NF fruit, respectively, indicating advanced maturity of F-FS and shade fruit relative to NF. Fruit quality attributes (firmness, soluble solids (SS), total acids and extractable juice) were analyzed at 2, 4 and 5 months of regular atmosphere storage (-1°C), following a 7-day, 20°C ripening period. Slightly greater levels of SS were observed in FS fruit. Shade treatment fruit were significantly less firm and had lower sugar content.