Influence of Orchard Design on 'Owari' Satsuma Mandarin Citrus Unshiu(Marcovitch) Fruit Quality, Physiology, and Productivity

Abstract

Satsuma mandarin growers in Alabama attempt to mitigate freeze damage by using various orchard designs such as interplanting between pecan or pine trees, planting in open fields with microsprinkler irrigation, and planting behind windbreaks. The goal of this research was to determine the influence of different orchard designs on canopy temperature, photosynthesis, leaf area, specific leaf area, yield, and fruit quality of satsuma mandarins. Satsuma canopy temperature under dense pine tree canopy was warmer than control trees in an adjacent open field. All trees in orchard designs that experienced shading had reduced photosynthesis. Satsuma trees grown under pine tree and pecan tree canopies had greater leaf area, and tended to have thinner leaves (greater specific leaf area) when compared to trees grown in full sun. Fruit from trees under dense pine tree canopies had reduced fruit size, rind thickness, and vitamin C concentration. There were no differences in fruit soluble solids concentration due to the dense pine tree canopy treatment; however, fruit from moderate pine tree shading had increased soluble solids concentration when compared to trees grown in full sun. There was no reduction in photosynthesis, fruit size, rind thickness, juice weight, or juice volume for trees planted behind a windbreak. In addition to freeze protection, the effects on photosynthesis and fruit quality should also be considered when selecting an orchard design for satsuma mandarin production.