Formação de porta-enxertos de goiabeira sob diferentes salinidades da água de irrigação e ácido salicílico.

Abstract

In the Northeast region, guava has great socioeconomic importance, being widely cultivated, due to its great demand and acceptance by consumers, but its cultivation in areas that have high levels of salts in the water is a limiting factor due to its sensitivity to salt stress. Thus, the search for strategies capable of mitigating the deleterious effects on guava is of paramount importance for the expansion of irrigated cultivation, highlighting the foliar application of salicylic acid. In this sense, the objective of this study was to evaluate the growth, physiological indices, and quality of 'Paluma' guava seedlings irrigated with saline water and foliar application of salicylic acid during the rootstock formation phase. The research was conducted under greenhouse conditions, belonging to the Center of Technology and Natural Resources of the Federal University of Campina Grande (CTRN/UFCG), located in the municipality of Campina Grande, PB. The design used was randomized blocks in a 5 × 5 factorial arrangement, with five levels of electrical conductivity of water (0.6, 1.5, 2.4, 3.3, and 4.2 dS m-1) and five concentrations of salicylic acid (0, 0.8, 1.6, 2.4, and 3.2 mM), with four replications and two plants per plot. Salicylic acid up to a concentration of 1.3 mM increased the relative water content and decreased intercellular electrolyte leakage from the leaf blade of 'Paluma' guava seedlings. Foliar application of salicylic acid at a concentration of 1.7 mM attenuated the effects of salt stress on chlorophyll a of guava seedlings irrigated with water of up to 1.6 dS m-1. The concentrations of 1.6 and 1.5 mM of salicylic acid increased the levels of chlorophyll b and chlorophyll total, respectively. The harmful effects of salt stress on carotenoid concentration and quantum efficiency of photosystem II were not attenuated by the application of salicylic acid. The concentrations of salicylic acid applied via foliar spray did not attenuate the harmful effects of irrigation water salinity on the growth and quality of 'Paluma' guava seedlings.