Response to Deficit Irrigation of ‘Orogrande’ Mandarin Grafted onto Different Citrus Rootstocks in Spain

Abstract

Drought is increasingly becoming an abiotic stress factor that affects citrus yield in the Mediterranean Basin, and rootstocks may impact the plants’ responses to it. This study compares the influences of Forner-Alcaide 5 (FA-5), an emerging well-established rootstock in Spain, and Carrizo citrange (CC), the common commercial rootstock of the Orogrande mandarin variety, on plants’ responses to water reduction. The deficit irrigation (DI) condition was established by 50% irrigation and evapotranspiration (ETc). The canopy volume, yield, fruit size and fruit internal quality were evaluated. The yield reduction in the CC DI was mainly due to a smaller fruit size, but in FA-5, it was due to fewer fruits without an affected caliber. Regarding Ct, the fruits from the CC DI had lower juice contents and higher rind percentages, while the differences between the Ct and DI trees were smaller in the FA-5 rootstock. The most remarkable effect was the increase in total soluble sugars (TSS) for the DI treatment. To conclude, the FA-5 rootstock had the strongest influence on Orogrande mandarin under water stress. These results can be useful for addressing water stress problems in citrus.