Suitability of two dwarfing citrus rootstocks for ‘Salustiana’ orange trees grown under super-high-density conditions with mechanical harvesting

Abstract

ABSTRACT Even though super-high-density plantation systems could maximise yield per acre and induce an early entry production, a few research studies have been conducted on citrus crops in the Mediterranean Basin. In this study, we assessed the suitability of ‘Salustiana’ orange trees (Citrus sinensis) on two dwarfing rootstocks [Forner-Alcaide 418 (FA418) and Forner-Alcaide 517 (FA517)] under super-high-density plantation systems. Tree growth, yield and fruit quality of ‘Salustiana’ on both citrus rootstocks were evaluated. Furthermore, the suitability of mechanical harvesting was evaluated using an over-the-row continuous canopy shaker for this citrus plantation system. For this last purpose, the effects of mechanical harvesting on fruit detachment and fruit harvested and tree damage were analysed. The results showed that ‘Salustiana’ orange on FA517 obtained a better response than on FA418 in terms of vegetative growth, effective yield and fruit quality under super high-density conditions, also displaying a better response to mechanical harvesting with a high detachment efficiency of fruits. It emphasised the relevance of proper mechanical pruning to reduce the tree damage and improve the detachment efficiency by this canopy shaker. Thus, although the over-the-row canopy shaker requires some technical improvements, it showed a high potential for harvesting super-high-density citrus crops for the juice industry.