Rootstock strongly influences citrus tree performance, but information remains limited for some regionally important cultivars. ‘IAPAR 73’, an early-season sweet orange commonly grown in Paraná, Brazil, has not been previously evaluated for rootstock responses. This study assessed the long-term effects of nine rootstocks, including ‘Rangpur’ lime, ‘Swingle’ citrumelo, ‘Volkamer’ lemon, ‘Caipira DAC’ and ‘Trifoliate’ oranges, ‘Cleopatra’ and ‘Sunki’ mandarins, ‘Carrizo’ and ‘Fepagro C-13’ citranges, on vegetative growth, yield, production stability, and fruit quality under Brazilian subtropical conditions. Tree growth was monitored annually for 10 years (2003–2013) and analyzed at establishment (5 years) and full production (10 years) phases of the orchard. Yield and fruit quality were evaluated across multiple harvests, and total soluble solids (TSS) stability was quantified using the coefficient of variation. Rootstock effects were analyzed using linear mixed-effects models in a randomized complete block design, considering rootstock and year as fixed effects and blocks as random effects. Rootstock significantly influenced all evaluated traits. ‘Carrizo’, ‘Cleopatra’, ‘Sunki’, and ‘Caipira DAC’ induced vigorous canopy growth and higher cumulative yields to the scion, while ‘Volkamer’ showed high yield efficiency and production stability. ‘Swingle’ and ‘Trifoliate’ enhanced TSS, TSS/TA ratios, and juice quality stability but induced lower vigor and yield, similar to ‘Rangpur’. This study provides the first evidence-based guidance for ‘IAPAR 73’ production, demonstrating that rootstock diversification can maximize productivity, stability, and sustainability in citrus orchards.
Carvalho et al. (Wed,) studied this question.