Citrus crop performance and fruit quality in response to different scion-rootstock combinations

Aim of study: To address diversification of citrus cultivars to increase the variety and profitability of orchards to adapt them to environmental changes. Area of study: State of São Paulo, a subtropical region of southeastern Brazil. Material and methods: The study evaluated the phenological intervals, thermal sum, vegetative and productive performance, and fruit quality of the sweet orange cultivars ‘Rubi’ (R), ‘Lue Gin Gong’ (LGG) and ‘Valencia Delta Seedless’ (VDS) grafted onto 'Rangpur' lime (RL) and 'Swingle' citrumelo (SC). The field experiment was conducted over consecutive growing seasons 2018-2021. Main results: The duration of the phenological intervals was little influenced by the rootstocks. The harvest time was approximately 245 days after anthesis (DAA) for R, 402 DAA for LGG, and 407 DAA for VDS, regardless of rootstock. Scion cultivars grafted onto RL showed larger canopy volumes and greater weight, length, and diameter of fruits than those of SC trees, and the combinations with SC were more productively efficient than RL due to lower canopy volume. The R scion cultivar presented superior yield performance and fruit colouration than LGG and VDS. The physicochemical quality of the fruits showed improved results with the combinations of LGG/RL, LGG/SC, VDS/RL, and VDS/SC. Research highlights: These results may be useful when planning the diversification of scion/rootstock combinations for new orchards, identifying dual-market orange cultivars for industrial processing and natural consumption, and determining the combinations that are better adapted to undesirable climatic conditions.