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The objective this study was to evaluate the effects of foliar application of ascorbic acid – AsA on the production and postharvest quality of sour passion fruit under deficit irrigation strategies. The experimental design was randomised blocks, in a split-plot scheme, with plots consisting of six strategies of irrigation with water deficit, based on crop evapotranspiration – ETc (irrigation with 100% ETc during the entire cycle – S1; irrigation with 50% ETc in the different stages: vegetative – S2; flowering – S3; fruiting – S4; and successively in the vegetative/flowering stages – S5; and vegetative/fruiting stages – S6) and three concentrations of AsA (0, 88.06 and 176.12 mg/L), with three replicates and three plants per plot. Water deficit reduces the production of sour passion fruit, regardless of the phenological stage of the plants without AsA application. Irrigation with water deficit in the flowering stage (50% of crop evapotranspiration) reduces the physical and chemical quality of sour passion fruits. Ascorbic acid in applied levels was effective in alleviating the effects of water deficit on production, with emphasis on the concentration of 176.12 mg/L on the quality of sour passion fruits, in the period from 160 to 220 days after transplanting. [ABSTRACT FROM AUTHOR]

The present study aimed to analyze the application of a seaweed biofertilizer as an attenuator of salt stress on the morphophysiology of scarlet eggplants. The experiment was carried out under protected conditions in Areia, PB, Brazil, using an incomplete factorial arrangement in a randomized block design with four replications and two plants per plot by adopting the Box Central Composite Design with five electrical conductivities of irrigation water – ECiw (0.50 – control, 1.15, 2.75, 4.35 and 5.00 dS m−1) and five concentrations of seaweed biofertilizer (0 – control, 1.45, 5.00, 8.55 and 10 mL L−1). The electrical conductivity of irrigation water at values starting at 0.5 dS m−1 negatively affected the growth of scarlet eggplants. Therefore, the crop is considered sensitive to salt accumulation. The increase in electrical conductivity of irrigation water negatively affected the morphophysiology of scarlet eggplants, with reductions higher than 10% at electrical conductivity values higher than 1.37 dS m−1. Biofertilization at 6.67 mL L−1 mitigates the effects of salt stress on the gas exchange variables and the phytomass accumulation of scarlet eggplants 60 days after sowing. The seaweed biofertilizer can be used to improve the physiological and morphological performance of scarlet eggplants. [ABSTRACT FROM AUTHOR]

The establishment of quality seedlings when irrigated with water with a high saline index has become a challenge for fruit growers in arid and semi-arid regions, requiring the adoption of techniques that will mitigate such effects. In this scenario, this study aimed to evaluate the effects of irrigation with saline water and foliar nitrogen fertilization on the formation of custard apple seedlings. The experiment was conducted in a randomized block design and arranged in a 5 × 5 factorial corresponding to five electrical conductivity levels of irrigation water—ECiw (0.5, 1.15, 2.75, 4.35, and 5.0 dS m−1) and five nitrogen levels applied on the leaves (0, 0.33, 1.15, 1.97, and 2.3 g L−1), with four replicates and two plants per plot, totaling nine combinations generated by Box's central composite design. Irrigation with the electrical conductivity level of 1.33 dS m−1 caused acceptable losses of up to 10% in the net photosynthesis rate, phytomass accumulation, and quality of custard apple seedlings. Nitrogen fertilization at the level of 1.45 g L−1 mitigated the effects of salt stress on the morphophysiology and quality of custard apple seedlings. The N level of 1.59 g L−1 associated with the ECiw of 0.5 dS m−1 increased the gas exchange, phytomass accumulation, and Dickson Quality Index of custard apple seedlings 90 days after emergence. The application N level from 0.95 ml L−1 maintains the acceptable quality of custard apple seedlings under irrigation conditions with water of 5.0 dS m−1. [ABSTRACT FROM AUTHOR]

Germination, floristic composition and phytosociology in the soil weed seed bank are important to know the weed flora and to predict weed infestations. The objective of this research was to assess and to compare germination, the weed flora and phytosociology of the soil weed seed bank in rice intercropped with corn fields in Maranhão State, northeastern Brazil by the germination method in the greenhouse and by weed sampling in the field. Phytosociological parameters computed were frequency, density, abundance and the importance value of each species. Diversity was assessed by the Shannon's Diversity Index. We recorded a total of 1,998 individuals from 40 species, 31 genera and 16 families from which 1,339 individuals germinated in the greenhouse and 659 in the field. Weed density was higher in the greenhouse (878 plants m-2) than in the field (261 plants m-2). The Cyperaceae family had the highest floristic richness with 12 species. The dominant species based on the importance value were Scleria lithosperma (IV = 37.0%) in the greenhouse and Lindernia crustacea (IV = 27.7%) in the field. Floristic diversity was higher in the greenhouse with H' = 2.66. These results could help to predict weed infestation potential and could lead to improved weed management practices in rice intercropped with corn fields in Maranhão State. [ABSTRACT FROM AUTHOR]

The objective of this research was to assess the density, floristic composition, phytosociology and diversity of a soil weed seed bank ex situ by germination in a greenhouse and in situ by weed sampling on a smallholder corn field located in Lago Verde County, Maranhão State. Fifteen pairs of 25 m2 plots were designated. In half of these plots, 90 soil samples were collected with an open metal template measuring 25 x 16 x 3 cm and placed in a greenhouse to germinate. In the other half, 90 weed samples were collected using the same metal template. We recorded a total of 1,998 individuals from 40 species, 31 genera and 16 families, from which 659 individuals germinated in situ and 1,339 ex situ. Density was higher ex situ, with 372 plants m-2. The Cyperaceae family had the highest floristic richness with nine species, followed by the Poaceae with six. The dominant species based on the Importance Value Index were Lindernia crustacea (IVI 27.7%) in situ and Scleria lithosperma (IVI 37.0%) ex situ. Floristic diversity was higher ex situ, with H' = 2.66 nats ind-1. These results could help predict infestation potential and could lead to improved weed management strategies in corn-growing areas on smallholdings in Maranhão State, northeastern Brazil. [ABSTRACT FROM AUTHOR]

The objective of this study was to select progenies of Opuntia undulata Griffiths cv. African Elephant Ear (AEE) through morphological, productive, and nutritional traits, and also evaluate the repeatability and selection gain. The experiment was carried out between 2018 and 2020, in the semiarid region of Brazil. A completely randomized design was used, with ten replications. The treatments consisted of 12 progenies of Opuntia undulata cv. AEE. Morphological, productive, and nutritional characteristics were evaluated, also the selection gain and repeatability were estimated. There was a variation in the productivity of up to 11.2 t DM ha−1. Progenies number 6 and 7 stood out in terms of selection gain. Progenies 6, 7, 9, and 12 were the most productive. Progeny 6 stood out in terms of dry matter production and minor presence of spines; both traits are of great interest in breeding programs of forage cacti. Based on the repeatability analysis, fewer evaluations were enough to predict with confidence morphological traits and dry matter production in different progenies of Opuntia undulata Griffiths. [Display omitted] • Fewer evaluations could predict the morphological traits in Opuntia undulata Griffiths. • Forage cacti Opuntia undulata Griffiths displays high repeatability for the morphological and productive traits. • Forage cacti Opuntia undulata Griffiths displays a superior in vitro dry matter digestibility. [ABSTRACT FROM AUTHOR]

The experiment was conducted in a greenhouse from May 1 to July 31, 2008, in Areia county, Paraiba State, PB, Brazil, in order to evaluate the effects of irrigation water salinity on initial growth of the passionfruit seedlings in non-saline substrate with and without bovine biofertilizer. The treatments were distributed in a completely randomized design, with three replications and twelve plants per plots, in a factorial arrangement 5 x 2 x 2, corresponding the former to the levels of salinity in the irrigation water: 0.5; 1.0; 2.0; 3.0 and 4.0 dS m-1, in soils with and without bovine biofertilizer applied at two moments (25 and 65 days after seedling emergence). The growth of the seedlings and the soil electrical conductivity were evaluated at the end of the experiment. The biofertilizer was diluted in a low saline water at a 1:1 ratio and was applied once two days before sowing, corresponding to 10% of the substrates volume. The increase in water salinity inhibited the growth in height of plants, leaf area and root length, but always to a lesser extent in the treatments with bovine biofertilizer. The increase in electrical conductivity of the irrigation water elevated the soil salinity, independently of the addition of biofertilizer. [ABSTRACT FROM AUTHOR]

Ecophysiological studies are highly important to seek understanding of the plant-environment relationship. The objective of this work was to evaluate the influence of environmental factors on physiological aspects in young plants of Erythroxylum pauferrense throughout the day. A completely randomized design with 10 treatments and 4 replicates was used. Treatments were at different evaluation times throughout the day (8:00 h-17:00 h) with a 60-minute interval between them. The physiological variables evaluated were: photosynthesis rate, internal CO2 concentration, transpiration, stomatal conductance, vapor pressure deficit, instantaneous water use efficiency, intrinsic water use efficiency, instantaneous carboxylation efficiency and leaf temperature. Internal and external temperature, relative humidity of the internal and external air of the greenhouse and photosynthetically active radiation were measured as climatic variables. The climatic variables presented correlations with the physiological parameters, with a strong association between photosynthetically active radiation and internal and external temperature of the greenhouse with the rate of photosynthesis, vapor pressure deficit, leaf temperature, transpiration, intrinsic efficiency of the use of water, stomatal conductance and instant water use efficiency. The influence of climatic factors on the physiological aspects in plants of E. pauferrense can be observed. The most suitable period of the day for conducting the physiological evaluations in species is between 11:00 h and 13:00 h. [ABSTRACT FROM AUTHOR]

The umbu tree is a species of the genus Spondias of big expression in the semiarid region, since it is present in all the Brazilian northeast. However, the lack of a propagation protocol is one of the barriers to commercial cultivation of this species. In this sense, the objective of this study was to evaluate the effect of the treatment in the matrix plant with zinc in the promotion of rooting of umbu tree cuttings treated with indolebutyric acid (IBA). It was adopted a completely randomized design with nine treatments at levels determined by the matrix "Central Box Compound" for zinc concentrations (0, 5.8, 20, 34.2 and 40 mg L-1) and combinations with concentrations of AIB (0; 872.35; 3000, 5127.65 and 6000 mg L-1) and four replicates. Each experimental unit consisted of 12 stakes. Treatment of matrix plants with zinc does not affect the development of roots and shoots of umbu tree cuttings. Indolbutyric acid promotes better development and rooting of umbu tree cuttings at the concentration of 6000 mg L-1. However, there is less growth of the aerial part of the cuttings with the use of this vegetal regulator. [ABSTRACT FROM AUTHOR]

The variability and low Watermelon yields in northeastern Brazil are linked to the lack of research on the fertilization management of culture. This experiment aimed to evaluate the watermelon production at soil under the levels cattle manure and potassium. The treatments were distributed in randomized block design with three replications and 21 plants per plot in factorial scheme 3 × 5 + 1, referring to three cattle manure levels (0.0 1.10 and 2.52 kg hole-1), five K2O levels (0.0; 7.5; 15; 22.5 and 30 kg ha-1), and one additional treatment (without organic and mineral fertilizers). Except additional treatment, the other treatments received nitrogen, in the form of urea (120 kg ha-1 N). Were evaluated: number of fruits per plant, average fruit weight, productivity and fruit size (longitudinal diameter fruit-LDF and equatorial diameter fruit-EDF). The K2O levels supplied were not sufficient to raise the average mass of watermelon fruits to satisfactory values. The 1.10 kg dose of bovine manure was the one that promoted higher values of productivity. The increase in the dose of manure reduced the need for potassic fertilizer to increase the productivity of watermelon plants. [ABSTRACT FROM AUTHOR]