Production and postharvest quality of yellow passion fruit cultivated with saline water and hydrogen peroxide

The present study aimed to evaluate the production and postharvest quality of yellow passion fruit, cultivated under different levels of irrigation water salinity and exogenous application of hydrogen peroxide. At low concentrations, hydrogen peroxide may favor plant acclimatization when subjected to saline stress conditions due to the activation of defense mechanisms. The experiment was conducted in greenhouse in the municipality of Campina Grande-PB, Brazil, using drainage lysimeters filled with sandy loam Entisol. The experimental design was randomized blocks, with 4 x 4 factorial arrangement with three replicates, consisting of four levels of irrigation water electrical conductivity--ECw (0.7, 1.4, 2.1 and 2.8 dS [m.sup.-1]) and four concentrations of hydrogen peroxide--[H.sub.2][O.sub.2] (0, 20, 40 and 60 [micro]M). The different concentrations of [H.sub.2][O.sub.2] were applied by soaking the seeds for a 24-h period before sowing and spraying the leaves on the adaxial and abaxial sides. At the end of the cycle (205 days after transplanting-DAT), passion fruit production was evaluated by determining the number of fruits per plant, mean fruit weight and total fruit weight. Postharvest quality was determined by physical characterization of fruit (equatorial and polar diameters and rind and pulp thicknesses), hydrogen potential in the pulp, titratable acidity and ascorbic acid. Increasing levels of irrigation water salinity negatively affected the production and physical and chemical quality of passion fruits. Number and total weight of fruits per plant were the most compromised variables. There was significant interaction between irrigation water salinity levels and [H.sub.2][O.sub.2] concentrations on fruits' polar diameter, at 205 days after transplanting. Foliar application at estimated concentration of 27.5 and 41.5 [micro]M [H.sub.2][O.sub.2] led to the highest values of total titratable acidity and vitamin C, respectively, at 205 DAT. Water salinity above 0.7 dS [m.sup.-1] resulted in changes in the physico-chemical characteristics of passion fruit. Peroxide concentrations up to 60 [micro]M did not mitigate the deleterious effects of salt stress on passion fruit yield and quality in the first crop cycle. Keywords: Passiflora edulisf. Flavicarpa; reactive oxygen species; acclimation; salt stress; semi-arid