Gas exchange and yellow passion fruit production under irrigation strategies using brackish water and potassium

Abstract

The occ urrence of water sources with high concentrations of salts is a common problem in the semi-arid region of north-eastern Brazil. The search for management strategies that can minimize the effect of salt stress on crops is therefore extremely important. As such, this study aimed to evaluate gas exchange and production in the yellow passion fruit 'BRS GA1'as a function of irrigation strategies using brackish water and doses of potassium. The research was carried out under fi eld conditions in São Domingos, in the state of Paraíba, Brazil, using a randomized block design in a 6 × 2 factorial scheme, with treatments comprising six irrigation strategies using water (irrigat ion with low-salinity water throughout the cycle -WS; irrigation with high-salinity water during the vegetative stage -VE; during the fl owering stage -FL; the fruiting stage -FR; during successive vegetative/fl owering stages -VE/FL; successive vegetative/fruiting stages -VE/FR) and two doses of potassium (60% and 100% of the recommended dose of 345 g K 2 O per plant per year), with four replications and three plants per plot. Two levels of water salinity (1.3 and 4.0 dS m -1 ) were used during different phenological stages of the crop. Irrigation with water at 4.0 dS m -1 reduced the leaf water potential, leaf osmotic potential, stomatal conductance, transpiration, and rate of CO 2 assimilation of the yellow passion fruit, regardless of the irrigation strategy. The continuous salt stress during the vegetative and fl owering stages compromised production in the yellow passion fruit.

Brackish water irrigation strategies and potassium fertilization in the cultivation of yellow passion fruit

“…Plant spacing and formative and cleaning prunings were according to Pinheiro et al (2022). The second cycle started after the crown cleaning (at 254 DAT) carried out at the end of the fruiting stage of the first cycle.…”

Potassium fertilization in the cultivation of sour passion fruit under irrigation strategies with brackish water

“…At 61 days after sowing (DAS), transplanting was performed to the area in the field. Brackish water irrigation management started at 50 DAT (Pinheiro et al, 2022).…”

“…The spacing used was 3 m between rows and 3 m between plants, using the vertical trellis system with smooth wire n° 14. Formative pruning, pollination, and other cultural practices and phytosanitary control were carried out as described by Pinheiro et al (2022).…”

“…The high concentrations of salts present in irrigation water can induce physiological changes that compromise growth, development and the physicochemical quality of fruits (Silva et al, 2019a;Pinheiro et al, 2022). Among the strategies that can reduce the impacts of salt stress, the use of brackish water in the stages in which the crop has greater tolerance (Lima et al, 2020a;Soares et al, 2021) and potassium fertilization (Gurgel et al, 2010) stand out, because the tolerance of plants to salinity may vary between cultivars of the same species, with the phenological stage of the crop and with the duration of the exposure to salts (Silva et al, 2022). Pinheiro et al (2022), in a study with sour passion fruit under brackish water irrigation strategies varying the phenological stages of the crop, concluded that the passion fruit 'BRS GA1' is sensitive to salt stress in the vegetative and flowering stages continuously.…”

“…Among the strategies that can reduce the impacts of salt stress, the use of brackish water in the stages in which the crop has greater tolerance (Lima et al, 2020a;Soares et al, 2021) and potassium fertilization (Gurgel et al, 2010) stand out, because the tolerance of plants to salinity may vary between cultivars of the same species, with the phenological stage of the crop and with the duration of the exposure to salts (Silva et al, 2022). Pinheiro et al (2022), in a study with sour passion fruit under brackish water irrigation strategies varying the phenological stages of the crop, concluded that the passion fruit 'BRS GA1' is sensitive to salt stress in the vegetative and flowering stages continuously.…”