Brave bean (Capparis flexuosa L.) is a Caatinga species that is used as forage, mainly during the dry season when some plant species lose their leaves. The aim of this study was to assess genetic diversity within and among brave bean populations using Random Amplified Polymorphic DNA (RAPD) markers. Brave bean leaves were collected from 30 accessions in the following municipalities of Paraíba state, Brazil: Barra de Santa Rosa (BSR), Cuité (C), São João do Cariri (SJC), Damião (D), Baraúna (B), and Picuí (P). DNA extraction followed the standard methodology of CTAB with modifications. RAPD analyses were carried out using 18 primers, and polymorphism of the amplified DNA fragments was visualized using agarose gel electrophoresis. Data were used to calculate Jaccard Similarity Coefficient values, which were then used to group samples with the Unweighted Pair Group Method with Arithmetic Mean. Cophenetic Correlation Coefficient, Stress, and Distortion Coefficient values were also calculated from these analyses. Band polymorphism was generated with 14 primers, but the sampled populations showed low numbers of polymorphic loci (27 in BSR, 18 in C, 7 in SJC, 9 in D, and 0 in B and P). The highest polymorphic information content was found in samples from the BSR (9 groups), C (22 groups), SJC (7 groups), and D (6 groups) municipalities. In the interpopulation analysis, 34 groups were formed, the matrices of which showed high cophenetic correlations (0.95 to 0.98), but low stress (12.9 to 17.45%) and distortion (3.05%). Therefore, results showed that there was genetic variability both among and within brave bean populations.

The objective of this study was to evaluate the effect of different doses of bovine biofertilizer on yield and post harvest of the strawberry crop in different growing environments. The experiment was carried out in two cycles of production, in Fortaleza, Ceará. The experimental design was in randomized blocks, arranged in subdivided plots, where the plots were of three cultivated environments (A1 = protected environment with screens, cold-water spraying, and white floor; A2 = environment with full sun, cold-water spraying, and white floor; A3 = environment with full sun, no cold-water spraying, and grey floor). The subplots consisted of five doses of biofertilizer (D1 = 0,0, D2 = 500, D3 = 750, D4 = 1000 and D5 = 1250 mL plant-1 week -1), with five replications. In the two-year period, the dose was higher in the protected environment of the weed type, with nebulization and on the white floor, at the dose of 500 mL week-1 plant-1 in the first cycle and 325 mL week-1 plant-1 in the second cycle. The dose of bovine biofertilizer of 1250 mL week-1 plant-1 promotes a longer duration and duration of the first cycle. During the second cycle, as the bovine biofertilizer doses of 585 and 620 provide higher and lower output than the protected environment. The environment without nebulization and on the floor without painting, the best soluble practices (Brix) in relation to the protected environment of the type screened and a full sun with nebulization.

Water availability and substrate type are essential factors in seed germination tests, influencing imbibition and seedling development. The objective of this study was to evaluate the influence of two substrates and different water volumes on the germination and vigor of chia seeds. The experimental design was completely randomized in a 2 x 6 factorial scheme, which consisted of two substrates, paper towel (Germitest®) and blotting paper, soaked with six water volumes equivalent to 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 times their dry weight, in four replicates of 50 seeds each. Germination percentage, mean time of germination, shoot length, radicle length, shoot dry matter, radicle dry matter, total dry matter (seedling), and root/shoot ratio were evaluated. Based on our results, germination tests for seeds of chia should be conducted using blotting paper (on paper) as substrate, with a water volume of 2.5 to 4.0 times its dry weight. Chia seedlings grown on blotting paper showed greater growth and dry matter accumulation compared to those grown on paper towel.

Vegetable production is an impactful activity, characterized by intensive land use, high input demand, and it requires strategic management adoption, especially in sustainable production systems, where the pillars of sustainability (environmental, social and economic) must be respected. In this sense, the objective of this work was to evaluate economic indicators of lettuce production using Caatinga spontaneous species (Calotropis procera: rooster tree) as fertilizer and cultivated in two seasons (spring and fall-winter) in the municipality of Serra Talhada, PE. The experimental design was in randomized blocks, arranged in a 4 x 4 factorial scheme, with three replications. The first factor was the biomass amounts of green manure (5.4, 8.8, 12.2 and 15.6 t ha-1 on a dry basis); and the second was their incorporation times in the soil (0, 10, 20 and 30 days before lettuce transplanting). The green mass yield, production costs, rate of return, and net profit margin were determined. The amount 15.6 t ha-1 of C. procera allowed higher profitability to the organic production of lettuce, and it is considered ideal to incorporate the green manure 11 (spring) and 15 (fall-winter) days before transplanting the vegetable. The spring crop promoted a superior economic return to the fall-winter planting, demonstrating economic viability even in the smallest amount of C. procera.

The presence of microorganisms, especially during storage, can lead to the rapid deterioration of macauba fruits (Acrocomia aculeata) and reduce the quality of extracted oil for biodiesel production. An alternative to ensure the quality of the oil is the use of ozone gas, a oxidizing agent that has high antimicrobial and sanitizing power. The objective of this study was to evaluate the influence of high concentrations of ozone gas on macaúba fruit and its effect on the quality of the oil throughout storage for the production of biodiesel. Ozonation was performed 20 days after harvest using fruits with and without the epicarp. Ozone was applied at a concentration of 18.0 mg L-1 and a flow of 1.5 L min-1 for 10 h. After ozonation, the fruits were stored for different periods, and the physical-chemical parameters of the oil were evaluated. The ozonation of fruits without the epicarp visually reduced microorganism attack. In general, the ozonation process of macauba fruits maintained the visual characteristics of the fruits and the physical-chemical characteristics of the oil for biodiesel production compared to untreated fruits. The average acidity values of the oil were lower in the treatments with the ozone gas. Removal of the epicarp tends to facilitate the ozonation process, potentially by improving gas penetration into the fruit.

Sunflower can be an economically viable crop in the Northeast region of Brazil depending on the use of appropriate irrigation and fertilization managements. The objective of this work was to evaluate production components of sunflower plants (Helianthus annuus L.) of the BRS-324 cultivar subjected to different organic fertilizer rates (goat manure) and irrigation water depths in two crop cycles (November 2014 to February 2015; and August to November 2015). The experiment was conducted in a randomized block design with a split-split-plot arrangement, consisting of five organic fertilizer rates (OFR) (0, 300, 600, 900, and 1.200 mL plant-1 week-1) and five irrigation water depths (IWD) (33; 66; 100; 133, and 166% of the class A tank evaporation), with three blocks. The highest achene yield (1,220.78 kg ha-1) in the first cycle was found using OFR of 1,200 mL plant-1 week-1 and IWD of 134.9% (524.9 mm); and the highest yield (882.07 kg ha-1) in the second crop cycle was found using the highest OFR combined with IWD of 166% (843.0 mm). The use of goat manure as organic fertilizer had no effect on the sunflower oil content; however, this variable was affected by the irrigation water depths used. Protein content was higher in the second crop cycle (14%) when using IWD of 100% and OFR of 536 mL plant-1 week-1.

The accumulation and transformation of organic matter in the soil are fundamental for the maintenance and improvement of the chemical, physical, and biological attributes of the soil, and consequently, for the tropical forests functioning. The objective of this study was to evaluate the influence of secondary forests with different successional stages on soil organic matter, carbon and nitrogen stocks, and soil fertility. Three areas of seasonal semideciduous forest, located in Pinheiral - RJ, with different successional stages were selected: initial stage forest - ISF, medium stage forest - MSF, and advanced stage forest - ASF. The values of total carbon and nitrogen, C and N stocks, δ13C (‰) isotope, chemical and granulometric fractionation of soil organic matter, and soil fertility were determined. Based on the values of δ 13C (‰), it was verified that most of the soil carbon of the different successional stages comes from forest species (C3 plants). The areas with the highest succession time (MSF and ASF) possess higher levels of carbon and nitrogen contents and stocks, and carbon associated with minerals compared to ISF. In addition, ASF showed increased phosphorus, fulvic acid, humic acid, whereas soil density exhibited reduced values when compared to that of other areas. The MSF showed, in general, greater fertility of the soil. This study emphasizes the importance of secondary forests that, even in the initial stages of succession, have great potential to store and stabilize organic carbon in the soil.

Monosporascus root rot and vine decline (MRRVD) is an important disease in the melon crop in Brazil. In our research, we evaluated the reaction of 45 melon genotypes to M. cannonballus in two successive cropping seasons in a greenhouse. Melon seedlings were transplanted into naturally infested soil. The evaluation of the genotypes was performed after 55 days, using a score scale to group each genotype into one of five classes and to calculate the disease severity index. None of the genotypes showed an immune reaction to M. cannonballus, regardless of the season. In the first cycle, only 28.9% ('AF 464', 'Auraprince', 'DRG 2278', 'Estoril', 'Guaporé', 'Kousto', 'Mabel', 'Magisto', 'Massaï', 'Nectar', '8530', 'RZ 34130' and 'RZ 34292') had a similar reaction to the high resistance to the MRRVD. Most genotypes (66.7%) behaved as moderately resistant while 4.4% were susceptible and none were highly susceptible. Conversely, in the second cycle, no genotype showed a reaction similar to high resistance while 42.2% behaved as moderately resistant, 48.9% as susceptible, and 8.9% as highly susceptible. The severity levels ranged from 7.5 to 60% and 27.5 to 92.5% for the first and second cycles, respectively. The genotypes 'DRG 2278', 'Estoril', 'Guaporé', 'Kousto', 'Mabel', 'Massaï', 'RZ 34130' and 'RZ 34292' were identified as highly resistant and moderately resistant in the first and second cycles of cultivation, respectively. Therefore, these genotypes are promising sources of resistance to M. cannonballus and should be preferred in commercial fields infested with the pathogen.

Nitrogen fertilization is a limiting factor for grapevine production; its excess or deficiency can cause changes in fruit quantity and quality. Thus, the objective of this work was to evaluate productive parameters of grapevines of the Isabel-Precoce cultivar subjected to nitrogen and organic fertilization in the western semiarid region of the state of Rio Grande do Norte (RN), Brazil. The experiment was conducted at the Experimental Farm of the Federal Rural University of the Semi-Arid Region, in Mossoró, RN, Brazil, during two production cycles. The soil of the area used was classified as dystrophic Red Argissolo (Udult) of sandy texture. The experiment was conducted in a randomized block design with six replications, using a 5×2 factorial arrangement, with 5 nitrogen fertilizer rates (0, 30, 60, 90, and 120 kg ha-1) and two organic fertilizer rates (0, and 20 m3 ha-1 of bovine manure). The production components number of bunches per plant, grape production per plant, grape yield, weight, length and width of bunches, number of berries per bunch, and ten-berry weight were evaluated. The nitrogen rates and organic fertilizer rates used were significant (p=0.05) for all evaluated components. The N rate of 60 kg ha-1 combined with the organic fertilization generated the best results for the analyzed variables. N rates from 60 to 120 kg ha-1, applied singly or combined with organic fertilizer, hindered the production components of the Isabel-Precoce grapevines.

The aim of this study was to assess the productive performance of cowpea cultivars with different growth habits as a function of population density in the MATOPIBA region, Brazil. The experiments were carried out in Magalhães de Almeida, MA in the agricultural season 2014/2015. The cultivars BRS Itaim, BRS Tumucumaque, and BRS Pajeú, which present an erect, semi-erect, and semi-prostrate growth habits, respectively, were assessed. For the erect and semi-erect cultivars, a total of 8, 12, 16, 20, 24, and 28 plants m−2 were used whereas for the semi-prostrate cultivar, a total of 2, 6, 10, 14, 18, and 22 plants m−2 were used. The experimental design was a randomized block design with four replications and treatments composed of plant densities. Grain yield and number of pods per area presented a quadratic response to the increased plant density whereas a decreasing linear response was observed for the number of pods per plant. The maximum grain yield of erect, semi-erect, and semi-prostrate cultivars were 1,076 kg ha−1 (19.5 plants m−2), 1,252 kg ha−1 (18.7 plants m−2), and 755 kg ha−1 (14.5 plants m−2), respectively. The number of pods per area was the character that most correlated (P<0.01) with grain yield, regardless of the plant growth habit.