Cashew cultivation under water deficit and foliar application of salicylic acid

Abstract

The early-maturing dwarf cashew tree is a crop of great importance in the semi-arid Northeast of Brazil, due to its economic and social returns. However, prolonged periods of drought have hindered the expansion of its cultivation. To face this challenge, it is necessary to adopt irrigation management strategies and the use of osmoregulators. The effects of salicylic acid vary according to the acid concentration, the application method, the phenological phase of the plant, and the genotype. In this context, the objective was to evaluate the growth, chlorophyll index, membrane damage, and quality of early-maturing dwarf cashew genotypes under water stress and salicylic acid concentrations in the semi-arid region of Paraíba. The experimental design adopted was a randomized block design, arranged in a 3 × 2 × 4 factorial scheme, with treatments resulting from the combination of three cashew rootstocks (CCP 76, Faga 11, and Embrapa 51), two water conditions (full irrigation at 100% of actual evapotranspiration – ETa and water deficit at 40% of ETa), and four concentrations of salicylic acid – SA (0, 1.5, 3.0, and 4.5 mM), with three replications and two plants per plot. Application of salicylic acid up to 3.0 mM promoted a beneficial effect on the growth, chlorophyll index, and quality of cashew seedlings in the Embrapa 51 and Faga 11 genotypes under water restriction conditions. Application of 4.5 mM salicylic acid inhibited the growth, chlorophyll index, and quality of cashew seedlings. The Embrapa 51 genotype was the most sensitive to water deficit in the absence of salicylic acid application.