Rootstock-dependent growth, physiological responses and water-use efficiency of 'Tahiti' acid lime under deficit irrigation

Climate change and increasing water-related risks reinforce the need to select adapted rootstocks and efficient irrigation strategies for ‘Tahiti’ acid lime. This study evaluated the biometric and physiological responses of plants grafted onto five rootstocks and subjected to four water-management strategies in a four-year-old drip-irrigated orchard located in a dry subhumid climate region. The experiment was conducted in a randomized block design with three replicates in a 5 × 4 factorial scheme. The evaluated rootstocks were Swingle citrumelo, Flying Dragon, BRS Matta, LVK × LCR-38, and HTR-069, under rainfed conditions, full irrigation, moderate deficit irrigation, and severe deficit irrigation. Irrigation timing was determined by monitoring soil water content throughout the soil profile using TDR probes. Plant growth, yield, production efficiency, water-use efficiency, gas exchange, and leaf water potential were evaluated. Rootstock genotype significantly affected vegetative vigor, plant height, rootstock stem diameter, cumulative yield, canopy volume, production efficiency, and water-use efficiency. Irrigation management affected biometric variables depending on the evaluation year and altered gas exchange and leaf water potential. No significant interactions between irrigation management and rootstock were observed for the biometric and physiological variables. Flying Dragon and BRS Matta showed higher yields and production efficiencies. Water-use efficiency was inversely proportional to the applied irrigation depth. Therefore, these rootstocks are promising alternatives for irrigated and rainfed orchards under subhumid climate conditions. However, Flying Dragon requires further monitoring because of its reported sensitivity to water stress under conditions of regional climate variability.