Morfofisiologia de porta-enxertos de cajueiro irrigados com águas de distintas salinidades.

Abstract

Cashew tree is a fruit of socioeconomic importance for the northeastern region of Brazil, however, the high genetic variability of the orchards has promoted reduced rates of productivity in the region. Moreover, in this region the water available for irrigation has varied quality, being common the use of waters with excess salts in the agricultural production, in order to damage the cultures in different stages of development. The aim of this study was to evaluate the tolerance of different cashew genetic material to the increase of salinity in irrigation water during the rootstock phase. The experiment was carried out in a protected environment (greenhouse) of the Center of Science and Technology Agro-Food of the Federal University of Campina Grande (CCTA / UFCG), located in the municipality of Pombal-PB. The experimental design was a randomized complete block design, in a 5 x 3 factorial scheme, with four replications and two plants per plot. The treatments consisted of five levels of electrical conductivity of the irrigation water - CEa (0.3, 1.1, 1, 9, 2.7 and 3.5 dS m-1) and with three cashew rootstocks (Embrapa 51, CCP 76 and Crioulo). Gaseous exchanges, fresh and dry mass formation, and the quality of rootstocks are reduced by increasing ECa of irrigation water, however, irrigation with CEa water of up to 1.92 dS m-1, promotes acceptable reductions of 10% in the morphophysiology of the different genetic materials of cashew tree. The CCP 76 cashew tree rootstock presented the best results for the production of fresh, dry mass and Dickson quality index. The cashew rootstock Crioulo presented the best results for the physiological variables (CO2 assimilation rate, water use efficiency and instantaneous efficacy of carboxylation).