HIGHLIGHTS:
Potassium dose of 60% of the recommendation promotes greater polar diameter of sour passion fruit.
Regardless of irrigation strategy and K, the pH and titratable acidity of the pulp remain within the ideal range.
Salt stress in the vegetative and vegetative/fruiting stages stimulates the synthesis of flavonoids and anthocyanins.
ABSTRACT
In the Brazilian semiarid region, the occurrence of water sources with high salt concentrations stands out as a limiting factor for the production of most crops under irrigated conditions. This research was conducted to evaluate the physical and chemical quality of sour passion fruit as a function of brackish water irrigation strategies and potassium doses. The experiment was carried out under field conditions using a randomized block design in a 6 × 2 factorial scheme, consisting of six strategies of irrigation with brackish water (irrigation with water of 1.3 dS m-1 throughout the cycle - WS; irrigation with water of 4.0 dS m-1 in the vegetative stage - VE; flowering stage - FL; fruiting stage - FR; in the successive vegetative/flowering stages - VE/FL; vegetative/fruiting stages - VE/FR) and two potassium doses: 60 and 100% (345 g of K2O per plant per year) of recommendation, with four replicates and three plants per plot. Irrigation with water of 4.0 dS m-1 in the flowering stage or continuously in the vegetative and flowering stages reduced the yield and size of sour passion fruit. Fertilization with 60% of K is recommended for the production of sour passion fruits with greater polar diameter. It is feasible to cultivate sour passion fruit under irrigation with 4.0 dS m-1 of water in the flowering and fruiting stages and fertilization with 60% of the K recommendation without losses in ascorbic acid and total soluble sugars.
Key words:
Passiflora edulis; salt stress; bioactive compounds
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STA - Start of treatment application; SH - Start of the harvest
Bars with different letters indicate significant difference among treatments by Tukey test (p ≤ 0.05); WS - Irrigation with low-salinity water throughout the cultivation cycle (1-253 days after transplanting - DAT); salt stress in VE - Vegetative stage (50-113 DAT); FL - Flowering stage (114-198 DAT); FR - Fruiting stage (199-253 DAT); VE and FL - Vegetative and flowering stages (50-198 DAT); VE/FR - Vegetative and fruiting stages (50-113 and 199-253 DAT)
Bars with the same uppercase letters indicate no significant differences between potassium doses in the same brackish water irrigation strategy, and bars with the same lowercase letters for the same potassium dose indicate no significant differences between the brackish water irrigation strategies (Tukey test, p ≤ 0.05); WS - Irrigation with low-salinity water throughout the cultivation cycle (1-253 days after transplanting - DAT); salt stress in VE - Vegetative stage (50-113 DAT); FL - Flowering stage (114-198 DAT); FR - Fruiting stage (199-253 DAT); VE/FL - Vegetative and flowering stages (50-198 DAT); VE/FR - Vegetative and fruiting stages (50-113/199-253 DAT)
Bars with the same uppercase letters indicate no significant differences between potassium doses in the same brackish water irrigation strategy, and bars with the same lowercase letters for the same potassium dose indicate no significant differences between the brackish water irrigation strategies (Tukey test, p ≤ 0.05); WS - Irrigation with low-salinity water throughout the cultivation cycle (1-253 days after transplanting - DAT); salt stress in VE - Vegetative stage (50-113 DAT); FL - Flowering stage (114-198 DAT); FR - Fruiting stage (199-253 DAT); VE/FL - Vegetative and flowering stages (50-198 DAT); VE/FR - Vegetative and fruiting stages (50-113/199-253 DAT)