Morphophysiology of ‘Faga 11’ Cashew Rootstock Under Saline Water Irrigation and Exogenous Proline Application

Due to the reduced availability of good-quality water in the semi-arid region of Northeast Brazil, the utilization of saline waters in irrigation became an alternative for the expansion of agriculture in this region. Thus, it is necessary to develop techniques which can make viable the use of these waters in agriculture. Given the above, this study aimed to evaluate the morphophysiology of ‘FAGA 11’ cashew rootstock subjected to different levels of irrigation water salinity and exogenous proline application through the leaves. The experiment was carried out in a greenhouse of the Federal University of Campina Grande, at the Center of Sciences and Agri-Food Technology, Campus of Pombal, PB, Brazil, in a randomized block design, in 5 × 4 factorial scheme, with three replicates and two plants per plot. Treatments consisted of different levels of irrigation water electrical conductivity—ECw (0.3; 1.0; 1.7; 2.4 and 3.1 dS m-1) combined with proline concentrations applied through the leaves—PC (0; 4; 8 and 12 mM). Irrigations with water up to ECw of 1.37 dS m-1 may be used as it causes an acceptable 10% reduction in the variables of morphology of cashew FAGA 11 seedlings. The proline concentrations tested, with the exception of the Dickson’s quality index of seedlings, did not attenuate the deleterious effects of irrigation water salinity on the cashew FAGA 11 rootstock seedlings.