Leaf gas exchange and production of peanut under brackish water irrigation strategiesABSTRACT
Proper management of irrigation with brackish water can reduce the deleterious effects of salt stress on the peanut crop, considering application at more tolerant stages. The aim of this study was to evaluate the effects of salt stress applied at different phenological stages of the peanut crop. The experiment was conducted from February to April 2023 in an arch-type greenhouse. A completely randomized experimental design was used, with eight treatments and six replications, corresponding to strategies of irrigation with brackish water in the phenological stages: use of low-salinity water (W1 = 0.8 dS m-1) throughout the crop cycle; use of high-salinity water (W2 = 4.0 dS m-1) throughout the crop cycle; use of W2 only in the flowering and pod formation phases; use of W2 only in the vegetative and gynophore formation phases; use of W2 in the gynophore formation phase; use of W2 in the vegetative and flowering phases; use of W2 in the pod formation phase; use of W2 in the vegetative, flowering and gynophore formation phases. It is possible to irrigate the peanut crop with high-salinity water without production losses during the flowering, pod formation and gynophore formation phases. Irrigation with brackish water during the vegetative and flowering stages significantly reduces the average mass of peanut pods. In contrast, irrigation during the pod formation stage more strongly affects pod length and diameter.
Key words:
Arachis hypogea L.; salinity; phenological stage; photosynthetic activity; production components
HIGHLIGHTS:
Water use efficiency of peanut decreased when irrigated with 4.0 dS m-1 water during the vegetative stage.
Production of peanut was not affected by irrigation with brackish water (4.0 dS m-1) during the flowering and fruiting stages.
Peanut production is severely reduced by salt stress applied during the pod formation stage (37-80 DAS).
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VEG - Vegetative phase (0 - 14 days after sowing - DAS); FLO - Flowering phase (15 - 29 DAS); G.F - Gynophore formation phase (30 - 36 DAS); P.F - Pod formation phase (37 - 47 DAS); P.M - Pod maturation (47 - 80 DAS)
VEG - Vegetative phase (0 - 14 days after sowing - DAS); FLO - Flowering phase (15 - 29 DAS); G.F - Gynophore formation phase (30 - 36 DAS); P.M - Pod maturation (37 - 80 DAS)
S1 - Use of low-salinity water (W1 = 0.8 dS m-1) throughout the crop cycle; S2 - Use of high-salinity water (W2 = 4.0 dS m-1) throughout the crop cycle; S3 - Use of W2 only in the flowering and pod formation phases; S4 - Use of W2 only in the vegetative and gynophore formation phases; S5 - Use of W2 in the gynophore formation phase; S6 - Use of W2 in the vegetative and flowering phases; S7 - Use of W2 in the pod formation phase; S8 - Use of W2 in the vegetative, flowering and gynophore formation phases. Means followed by different letters indicate significant differences by Tukey’s test (p ≤ 0.05). Error bars represent the standard error of the mean (n = 6).
S1 - Use of low-salinity water (W1 = 0.8 dS m-1) throughout the crop cycle; S2 - Use of high-salinity water (W2 = 4.0 dS m-1) throughout the crop cycle; S3 - Use of W2 only in the flowering and pod formation phases; S4 - Use of W2 only in the vegetative and gynophore formation phases; S5 - Use of W2 in the gynophore formation phase; S6 - Use of W2 in the vegetative and flowering phases; S7 - Use of W2 in the pod formation phase; S8 - Use of W2 in the vegetative, flowering and gynophore formation phases. Means followed by different letters indicate significant differences by Tukey’s test (p ≤ 0.05). Error bars represent the standard error of the mean (n = 6).
S1 - Use of low-salinity water (W1 = 0.8 dS m-1) throughout the crop cycle; S2 - Use of high-salinity water (W2 = 4.0 dS m-1) throughout the crop cycle; S3 - Use of W2 only in the flowering and pod formation phases; S4 - Use of W2 only in the vegetative and gynophore formation phases; S5 - Use of W2 in the gynophore formation phase; S6 - Use of W2 in the vegetative and flowering phases; S7 - Use of W2 in the pod formation phase; S8 - Use of W2 in the vegetative, flowering and gynophore formation phases. Means followed by different letters indicate significant differences by Tukey’s test (p ≤ 0.05). Error bars represent the standard error of the mean (n = 6).
S1 - Use of low-salinity water (W1 = 0.8 dS m-1) throughout the crop cycle; S2 - Use of high-salinity water (W2 = 4.0 dS m-1) throughout the crop cycle; S3 - Use of W2 only in the flowering and pod formation phases; S4 - Use of W2 only in the vegetative and gynophore formation phases; S5 - Use of W2 in the gynophore formation phase; S6 - Use of W2 in the vegetative and flowering phases; S7 - Use of W2 in the pod formation phase; S8 - Use of W2 in the vegetative, flowering and gynophore formation phases. Means followed by different letters indicate significant differences by Tukey’s test (p ≤ 0.05). Error bars represent the standard error of the mean (n = 6).
S1 - Use of low-salinity water (W1 = 0.8 dS m-1) throughout the crop cycle; S2 - Use of high-salinity water (W2 = 4.0 dS m-1) throughout the crop cycle; S3 - Use of W2 only in the flowering and pod formation phases; S4 - Use of W2 only in the vegetative and gynophore formation phases; S5 - Use of W2 in the gynophore formation phase; S6 - Use of W2 in the vegetative and flowering phases; S7 - Use of W2 in the pod formation phase; S8 - Use of W2 in the vegetative, flowering and gynophore formation phases. Means followed by different letters indicate significant differences by Tukey’s test (p ≤ 0.05). Error bars represent the standard error of the mean (n = 6)