Ácido salicílico como atenuante do estresse hídrico em porta-enxertos de cajueiro anão precoce.

Abstract

The cashew tree is a crop that is of great importance in the semi-arid Northeast due to its economic and social return. However, the occurrence of prolonged periods of drought in the Brazilian semi-arid region has hampered the expansion of early dwarf cashew cultivation, making it necessary to adopt irrigation management strategies and the use of osmoregulators. In this context, the objective was to evaluate the physiology, growth, biochemistry and water relations of early dwarf cashew genotype under water stress and salicylic acid concentrations in the semi-arid region of Paraibano. The research was carried out in a greenhouse belonging to the Agro-food Science and Technology Center of the Federal University of Campina Grande, Pombal-PB. The experimental design adopted was in randomized blocks, arranged in a 3×2×4 factorial scheme, with treatments resulting from the combination of three cashew rootstocks (Embrapa 11, Faga 11 and CCP 76), two water conditions, corresponding to irrigation with 100% of the real evapotranspiration ETr (full irrigation) and another at 40% of the ETr (water deficit) and four concentrations of salicylic acid - AS (0; 1.5; 3.0 and 4.5 mM) with three repetitions and two plants per plot, totaling 144 experimental units. The growth and accumulation of phytomass of cashew rootstocks are harmed by the reduction of the irrigation depth by 40% of ETr. The Faga 11 genotype presents higher leaf production and leaf expansion rate than Embrapa 51. The concentration of 3 mM salicylic acid in rootstocks with water deficit provided an increase in stem diameter at 70 DAS. Application of 4 mM salicylic acid to rootstocks with ideal irrigation conditions reduces the accumulation of dry phytomass in the aerial part of the plants.