ABSTRACT Bromeliads are the target of predatory extractivism and consequently many species are included in the red list of threatened species, such as those belonging to the genus Neoregelia. Although Neoregelia mucugensis has not been evaluated for the degree of threat, its exploitation is exclusively extractive and its occurrence in Chapada Diamantina-BA is subject to the action of fires that affect the region annually. In this context, applying techniques aimed at protecting this genetic resource is fundamental for both the maintenance of its natural populations and the ex situ conservation of this genetic material. Plant tissue culture techniques have been successfully applied for the conservation of several bromeliad species. One of the methods used is slow growth, which consists in reducing plant metabolism and consequently decelerating its growth, which allows the maintenance of in vitro plant collections without the need for subculture. In this context, the objective of this study was to test the reduction of salts in the culture medium and the addition of osmoregulators on the induction of slow growth of N. mucugensis. Plants were subjected to treatments composed of different concentrations of MS medium and mannitol for a period of 12 months, when then analyses were conducted to evaluate growth, chlorophyll content and regeneration capacity of shoots in vitro. It was found that the treatment containing MS ½ and 7.8 g.L-1 of mannitol is indicated for in vitro conservation of N. mucugensis with maintenance of the regenerative capacity of its tissues.

ABSTRACT No isolated factor influences soybean development and production more than the sowing date, but the responses of cultivars sown on different sowing dates depends on their sensitivity to environmental conditions. Thus, this study evaluated the adaptability and stability of 17 soybean genotypes in relation to yield, as well as to the grain oil and protein contents as a function of different sowing times. The experiment was designed in randomized blocks with three replications and a 17 × 5 factorial scheme. The genotypes were: Conquista, CD 223 AP, Elite, Garantia, Bioagro lineage, M-Soy 8400, M-soy 8001, Nambu, Sambaíba, Esplendor, UFVS 2006, UFVS 2005, UFVTN 102, UVF 18, UFV 16, Valiosa, Vencedora, and the five sowing dates were: SD1 = 11/3, SD2 = 11/20, SD3 = 12/07, SD4 = 12/23, and SD5 = 01/09. The M-Soy 8001, UFV 18 and Garantia genotypes showed high oil contents, with adaptation to all sowing dates and stability when sown on the most favorable dates. The Bioagro lineage, CD 223 AP, and Garantia genotypes were adapted and stable when sown on all sowing dates and had higher protein contents than the other genotypes, regardless of the sowing date. The Elite, Nambu, and Garantia genotypes were adapted and stable when sown on the most favorable sowing dates and presented high grain yields when sown in early December. The findings indicate that the Garantia genotype is the most suitable for the growing conditions of the central-north region of the state of São Paulo.

ABSTRACT Splitting nitrogen (N) fertilizer application can be an efficient nutrient management technique to improve productivity and plant quality, as well as to reduce the negative environmental impact caused by N losses. In this context, the present study investigated how the management of N affects the agronomic characteristics of field-grown arugula plants. Nine treatments were assessed in a randomized complete block design, in a 4 x 2 + 1 factorial scheme, with three replicates. The evaluated factors were doses of N (60, 120, 180 and 240 kg N ha-1), split N fertilizer applications at side-dress (two and three times) and an additional treatment without a N supply. Maximum height was obtained with the application of 198 kg N ha-1. Nitrate content, fresh mass and productivity increased with increasing N doses. There was no effect of split N fertilizer applications on the characteristics evaluated. Therefore, the supply of 240 kg N ha-1 divided into two portions was considered as the best management strategy.

ABSTRACT Castor bean (Ricinus communis L.) is a plant native to Africa that presents important socioeconomic value for many countries, and has been the subject of breeding programs. In this context, the objective of this work was to identify genotypes with potential for improvement, focused on lowering plant height, using 19 hybrids and eight parents of R. communis. The study was developed at the experimental area of the Federal University of Recôncavo da Bahia in Cruz das Almas, BA, Brazil. The experiment was conducted in 2017 using a randomized block design with three replications, consisting of eight parents and 19 hybrids resulting from hybridization of these parents, grown with spacing of 3 meters between rows and 1 meter between plants. The characters stem diameter (SD), primary raceme insertion height (PRI), number of stem internodes (NSI), mean stem internode length (SIL), plant height (PH), number of harvested racemes (NHR), primary raceme length (PRL), and effective raceme length (ERL) were evaluated by analyzing the genetic parameters of variances and correlation between them. Five (H17, H2, H11, H13, and H6) of the 19 hybrids evaluated have potential to decrease PH of castor bean plants, presenting heights below 1.07 m. Direct selection for plant height is the most indicated for this purpose due to the high heritability of the character. However, the characters SD, PRI, and SIL stood out by assisting in indirect selection to decrease plant height because they can be early measured and present high heritability and strong correlation with PH.

ABSTRACT The use of filler liming in the sowing furrow can improve the chemical characteristics of the soil and, together with nitrogen fertilization, increase common bean yield. The objective of this study was to determine the effect of filler liming of the sowing furrow along with nitrogen topdressing fertilization on the yield of common bean, cultivar Pérola, irrigated by central pivot, in the Cerrado Region. The field experiments were conducted for three consecutive cropping years, in a randomized block design with four replications, in a 2x4 factorial scheme, consisting of two doses of nitrogen topdressing fertilization (zero and 60 kg ha-1 of N) and four doses of filler liming application in the sowing furrow (0, 200, 400 and 600 kg ha-1 of CaCO3). The plant density (PD), number of pods (NP), number of grains (NG), mass of 100 grains (M100) and, grain yield (GY) were evaluated. The use of 60 kg ha-1 of N provided greater M100 and GY. The increase of the filler liming doses in the sowing furrow led to a reduction of the NP. The filler liming dose of 200 kg ha-1 provided higher values of NG and M100, and when combined with the nitrogen topdressing fertilization, improved the GY of the common bean.

ABSTRACT The aim of the present study was to determine the beekeeping potential of Croton heliotropiifolius Kunth (Euphorbiaceae) based on flowering strategy, floral characteristics, available floral resources, and the individuals frequencies and foraging activities of Apis mellifera L. on its flowers in Fazenda Ingazeira, Brazil. Each C. heliotropiifolius plant possessed inconspicuous diclinous flowers clustered into 560 ± 60 dense terminal inflorescences containing 59 ± 12 pistillate and 160 ± 26 staminate flowers. Although both types of flowers produced nectar (pistillate: 2.8 ± 0.8 μL ; staminate: 0.3 ± 0.06 μL ), A. mellifera workers mostly visited staminate flowers (98%) during the peak visitation period (08:00-11:00 h). Moreover, during the foraging period, each plant produced approximately 5.376 × 10 8 pollen grains, ensuring approximately 33 visitation cycles from a colony of A mellifera workers that picked up an average of 405 pollen grains per visit per flower. Further, C. heliotropiifolius showed an annual cornucopia flowering strategy with high flower production for five months, which is an important characteristic that ensures floral resource availability in the environment. These findings suggest that C. heliotropiifolius has a great potential for apiculture in this region.

ABSTRACT This study was carried out with the objective of evaluating the water relations, photosynthetic pigments and growth of passion fruit cv. BRS Rubi do Cerrado, as a function of the cationic nature of irrigation water and exogenous application of hydrogen peroxide. The experiment was carried out under greenhouse conditions in Pombal – PB, Brazil. The experimental design was randomized blocks, in a 6 × 4 factorial scheme, corresponding to six cationic nature of water - CNW (S1 - Control; S2 - Na+; S3 - Ca2+; S4 - Na++Ca2+; S5 - Mg2+ and S6 - Na++Ca2++Mg2+) and four concentrations of hydrogen peroxide - H2O2 (0, 20, 40 and 60 μM), distributed in a randomized block design with four replicates. Plants in the control treatment (S1) were irrigated using water with electrical conductivity (ECw) of 0.3 dS m-1, while those of the other treatments (S2; S3; S4; S5 and S6) were subjected to ECw of 3.0 dS m-1, prepared with different cation(s). Application of 60 μM of H2O2 reduced the percentage of intercellular electrolyte leakage in plants irrigated with water of calcic composition. Salinity of water composed of sodium, sodium+calcium and sodium+calcium+magnesium, and H2O2 concentrations of 40 and 60 μM resulted in lower leaf water potential. The biomass accumulation of passion fruit was more sensitive to the variation of the electrical conductivity of the water. Regardless of the cationic nature, the use of water with electrical conductivity of 3.0 dS m-1 produced passion fruit seedlings with a Dickson quality index higher than 0.2, considered acceptable.

ABSTRACT Corn, one of the main grain crops in Brazil, needs to have its nutritional requirements fully satisfied to achieve high biological productivity. Thus, the objective of this work was to evaluate the influence of increasing doses of poultry litter biochar on nutrient concentrations in the leaves of hybrid corn BRS 2022 and in the soil after harvest. The experiment was carried out in a completely randomized design, with four replicates, evaluating six doses of biochar (0; 2.02; 4.05; 6.07; 8.10 and 10.12 t ha-1) and the plots composed of one plant per pot with a volume of 20 dm3. The collection of leaves for leaf diagnosis was carried out at the time of flowering, removing the opposite leaf from the ear base in the middle third region. These leaves were dried in a forced air circulation oven, 65 °C, for a period of 48 hours, ground, sieved through 20 mesh and analyzed for the concentrations of macronutrients in the leaf tissue. At the end of the experiment, 83 days after corn sowing, soil samples were collected as a function of the treatments and then analyzed chemically. Biochar application promoted an increase in the leaf contents of N, P and K, resulting in improvements in the nutritional status of plants for these nutrients. The chemical characteristics of the soil, analyzed after the corn harvest, revealed that there was an influence of the doses of biochar on the levels of calcium, organic carbon, potassium and phosphorus.

ABSTRACT Yellow passion fruit is a fruit species widely cultivated throughout the Brazilian semi-arid territory, but its yield is affected by the quality of the waters of this region. In this context, the objective was to evaluate the gas exchange and production of passion fruit cv. BRS Rubi do Cerrado irrigated with waters of different cationic natures. The study was conducted in drainage lysimeters under greenhouse conditions in Campina Grande, PB, Brazil, in a randomized block design, and the treatments were eight cationic natures of irrigation water (S1 - Control; S2 - Na+; S3 - Ca2+; S4 - Mg2+; S5 - Na+ + Ca2+; S6 - Na+ + Mg2+; S7 - Ca2+ + Mg2+ and S8 - Na+ + Ca2+ + Mg2+) with three replicates. Plants in the control treatment were irrigated with water of low electrical conductivity (ECw = 0.4 dS m-1), while those of the other treatments were irrigated using water with ECw of 3.5 dS m-1. The treatments Na+ + Ca2+, Na+ + Mg2+ and Ca2+ + Mg2+ were prepared in the equivalent ratio of 1:1, and Na++Ca2++Mg2+ in the ratio 7:2:1, respectively. Water salinity of 3.5 dS m-1 reduced gas exchange, and stomatal conductance and transpiration were the most sensitive variables of passion fruit. The number of fruits of passion fruit cv. BRS Rubi do Cerrado decreased with water salinity, regardless of the cationic nature. The waters of calcic and calcic+magnesian nature caused the greatest deleterious effects on the production variables of passion fruit, at 259 days after transplanting.

ABSTRACT The objective of this work was to characterize the physical and physicochemical parameters of pequi powders obtained by means of convective drying at different temperatures (50, 60, 70 and 80 °C) and pulp layer thicknesses (0.5, 1.0 and 1.5 cm). Initially, the physicochemical characterization of fresh pulp was carried out, followed by convective drying under the conditions mentioned, until the equilibrium moisture content and subsequent disintegration to obtain the powders. Subsequently, the physical and physicochemical properties of the obtained powders were analyzed and the best powder was selected based on reduced moisture content and water activity and lower peroxide index. Pequi pulp showed a high fat content and a yellowish color; with the increase in drying temperature, there were reductions in the moisture content, water activity and protein content of the powders. As for the color parameters, the powder showed a darkening with the increase in drying time; the water adsorption isotherms of the selected pequi powder were classified as Type II, and the GAB model showed the best fits. The pequi powders showed good solubility and low cohesiveness. The powder that showed good flowability was produced at a drying temperature of 60 °C and with pequi pulp layer thickness of 0.5 cm.