ABSTRACT Stress caused by soil water deficit has been one of the main factors that inhibit plant growth. The knowledge of the factors related to the behavior of weed species under water stress conditions can contribute to the elaboration of effective control strategies. Two experiments were carried out to evaluate the effects of the degree and duration of water deficit on physiological and growth indicators of two weed species (Bidens pilosa L. and Bidens subalternans DC.). The stress degree was simulated by four soil moisture: 100, 75, 50, 25% of total soil capacity. The water deficit duration was evaluated by five intervals of water supply: 0, 1, 2, 3, 4, 5, and 6 days. The experiments were carried out in a randomized complete block design with six replicates. The evaluated variables were: the photosynthetic rate (A; μmol CO2 m-2), stomatal conductance (gs; μmol H2O m-2 s-1), transpiration (E; mmol H2O m-2 s-1), number of leaves per plant, and dry matter of the roots, stems, leaves, and total. The results showed that the species of B. pilosa and B. subalternans tolerate low water availability conditions. Low stomatal opening and loss of leaves are mechanisms that ensure the survival of Bidens plants to the water deficit. However, water stress close to 25% of field capacity caused the death of species. The B. subalternans had higher sensitivity to the water deficit, showing a lower dry matter of leaf, stem, and root than B. pilosa.

ABSTRACT Cenostigma pyramidale, a pioneer species presents in all different successional stage (early, intermediate and late) of fifteen natural regeneration areas of Caatinga after land used changed and abandonment was used to investigates the morphological and physiological attributes that are very important to xeromorphic conditions as against herbivories. Leaf samples were collected to evaluate the percentage of the herbivory and index of sclerophylly. Anatomy, histochemistry, total phenolic content, epicuticular wax load, and n-alkanes profile were also performed. The results showed an inverse relationship between the percentage of herbivory and the index of sclerophylly. The leaves showed typical morphological and anatomical characteristics of xeric environments plants such as uniseriate epidermis and trichomes. Furthermore, it was also noticed a decrease in the overall thickness and the tissues according to the advancement of the successional stages. The histochemical revealed the presence of lipidic substances coating the epidermal layers, phenolics compounds stored in secretory structures, and starch in the mesophyll. The concentration of phenolics compounds indicating the difference from health leaves of plants between different stages of regeneration, but no difference when they were herbivored. The amount of cuticle wax did not change significantly with the successional stage. The profile of n-alkanes was characterized by the predominance of nonacosane (C29) and hentriacontane (C31). The C29 content decreases with the advancement of the successional stage, while the C31 content increases. All those attributes have a role to protect the plants to acclimate to the various environmental conditions of Caatinga.

ABSTRACT Using organic filters produced in local communities with low financial cost can reduce the environmental impacts caused by the disposal of untreated wastewater into receiving water bodies. In this study, the objective was to evaluate the efficiency of the filtration of swine wastewater (SWW) using banana stalk as an alternative material in an organic filter. SWW was applied to the organic filter and the filtered volume was converted into pore volume. Analyses of total solids, turbidity, color, total phosphorus, and total nitrogen were performed in the filter feed solution and effluent to evaluate treatment efficiency. Regression analyses were used to obtain equations in the estimation of the filtration performance in removing these variables from wastewater, with pore volume as an independent variable. The banana stalk filter did not remove total solids and color from the feed solution applied. Removal of 10–50% of SWW turbidity were obtained by the banana stalk. Banana stalk was highly efficient in removing nitrogen and phosphorus from SWW, reaching mean removals of 67% and 62%, respectively. In general, a banana stalk filter can be considered a promising alternative in the primary treatment of SWW.

ABSTRACT The lack of knowledge of the genetic parameters and the type of gene action results in difficulties to obtain varieties that combine agronomic and functional characteristics. The objective of this study was to determine the type of gene action associated with the contents of chlorophyll and agronomic characteristics in lettuce populations. The research was conducted at the Experimental Station of Vegetables, Monte Carmelo, Brazil. To perform the crosses and obtain the generations P1, P2, F1, F2, Bc1 and Bc2 the genotypes UFU-Albina#2, UFU-Albina#3, UFU-Lisa124#2#1, UFU-Crespa199#1#1 and UFU-Lisa217#5#2 were used as parents. The generations were evaluated for three characteristics: number of leaves, plant diameter and chlorophyll content. The parameters: genetic, phenotypic, environmental and additive variance, the dominance in F2, heritability in the broad and narrow-sense, the average degree of dominance based on averages, number of genes, the measure of the dominance deviations, additive effects and all interactions of ‘additive x additive’, ‘additive x dominant’ and ‘dominant x dominant’ type, were evaluated. Chlorophyll content was the most influenced by the environment. Plant diameter had the highest narrow-sense heritability for the cross UFU-Lisa-124#2#1 x UFU-Albina#3 (82.1%). The number of genes for the number of leaves varied from inconclusive to a minimum of 9 genes. The gene interactions for number of leaves were of overdominance type, while for plant diameter and for chlorophyll content the gene interactions were of partial dominance. The characteristics are suggested as being of polygenic or oligogenic nature.

ABSTRACT Garlic is a vegetable that has a high economic importance for Brazil. However, despite increases in garlic bulb production in the last years, Brazil is still dependent on imported garlic to meet the national demand. Thus, proper management practices and the use of virus-free clove-seeds are promising alternatives to ensure a high productivity and profitability. Thus, the objective of this work was to evaluate production characteristics and profitability of conventional and virus-free garlic crops as a function of different clove-seed sizes and plant spacings. Two experiments were conducted simultaneously, using virus-free and conventional garlic plants in Portalegre, state of Rio Grande do Norte, Brazil, in a randomized block experimental design, with four replications. The treatments were arranged in split-plot, with the clove-seed size (large and small) in the plots, and the spacing between plants (7.5, 10.0, 12.5, and 15.0 cm) in the subplots. The combination between the use of virus-free clove-seeds, large clove-seed size, and spacing of 12.5 cm between plants resulted in the highest commercial bulb yield and net income, R$ (BRL) 85,151.00 ha-1. The use of large clove-seeds and spacing of 7.5 cm between plants are recommended for conventional garlic crops.

ABSTRACT This work aimed to evaluate the physiological and biochemical changes resulting from controlled deterioration in different lots of sunflower seeds. Two sunflower seed lots of the cultivar Hélio 253 were subjected to simulated deterioration, using the accelerated aging test methodology (41 °C and 100% RH) for 0, 48, 72, and 96 h. Then, the seeds were subjected to the tests of germination, first germination count, seedling length and dry matter, emergence, accelerated aging, electrical conductivity, and total seedling length. The antioxidant activity was evaluated through the enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), and peroxidase (POX) at 0, 2, 4, and 6 days after sowing. Deterioration caused a reduction in the germination and vigor of the seeds, mainly in the lot with lower initial vigor and for the longest exposure times (72 and 96 h). For both lots, reductions in SOD activity and increases in POX and APX were observed during seed germination, mainly after 48 h of exposure to aging deterioration. Peroxidase enzymes are activated in deteriorated and non-deteriorated sunflower seeds, mainly after two days of germination.

ABSTRACT Alternative management measures have been used to reduce nematode population levels in affected areas. In this perspective, the objective was to evaluate the efficiency of nematicides based on fungus and bacterium, associated with poultry litter applied via ground in the management of Pratylenchus brachyurus and Heterodera glycines in soybean and corn crops in succession. The experiment was conducted in the 2018/19 growing season in the municipality of Ipameri– GO (-17°34’55.58”S−48°12’02.35”O) in naturally infested field, arranged in a randomized block design, with 10 treatments and 4 replicates, being: T1- Witness/ control, T2- Poultry litter, T3- P. lilacinum + T. harzianum, T4- B. subtilis + B. licheniformis, T5- P. chlamydosporia, T6- Abamectina, T7- P. lilacinum + T. harzianum + Poultry litter, T8- B. subtilis + B. licheniformis + Poultry litter, T9- P. chlamydosporia + Poultry litter, T10- Abamectina + Poultry litter. The poultry litter was added in the soil 10 days before planting. The plots were composed of 6 lines of 6 m, with a spacing of 0.5 m. In the soybean crop at 45 and 90 days after sowing (DAS), the fresh weight of the roots (MFR), nematological variables and productivity were evaluated. In corn, only nematological variables were evaluated at 60 DAS. The treatments using P. lilacinum + T. harzianum and B. subtillis + B. licheniformes increased the MFR and reduced the number of P. brachyurus and H. glycines at the root. P. chlamydosporia associated with poultry litter increased in productivity in soybean plants.

ABSTRACT Melon is a vegetable of great socioeconomic importance, and its cultivation is carried out under different production systems. The protected cultivation of melon can be carried out in coconut shell fiber, which is a substrate widely used in olericulture, but little information is available regarding its continuous use in more than one cultivation cycle. Therefore, this study aimed to evaluate the performance of muskmelon hybrids as a function of the reuse of coconut shell fiber with fertigation in a protected environment. The experiment was carried out in a greenhouse from March to July 2008 and designed in randomized blocks in a 2×3 factorial arrangement, with four replications. The factors consisted of two hybrids (‘Bonus 2’ and ‘Fantasy’) and three types of substrate (S1: new coconut shell fiber; S2: coconut shell fiber reused once in sweet pepper cultivation; and S3: coconut shell fiber reused twice, i.e., first in sweet pepper cultivation and then in melon cultivation). Transverse and longitudinal fruit diameter, fruit shape index, transverse and longitudinal locule diameter, locule shape index, peduncle insertion diameter, mesocarp thickness, firmness, skin netting, fresh mass, soluble solids, titratable acidity, pH, and yield were evaluated after harvest. Reusing twice the coconut shell fiber as a substrate did not affect the agronomic and physicochemical characteristics of the hybrids Bonus 2 and Fantasy.

ABSTRACT The interaction between Meloidogyne and Fusarium can alter the resistance behavior of passion fruit genotypes. The study was aimed to evaluate the reaction of genotypes of Passiflora spp. to Meloidogyne incognita race 3 (Mi)-Fusarium solani (Fs) complex. The assay was carried using RBD in the factorial arrangement: 10 genotypes (BRS-SC, M-19-UFV, P. alata, P. nitida, P. giberti, P.setacea, P. mucronata, P. murifolia, P. cincinnata, P. ligularis) x 3 treatments (Mi, Mi+Fs, Fs). After 180 days of planting the reaction to Mi was determined by RF (Pi/Pf) and to Fs by lesions size in roots and stems. According to the criteria of Oostenbrink and Moura and Regis, BRS-SC, M-19-UFV. P. alata and P. cincinnata behaved as resistant and P. giberti as susceptible. According to the Taylor and Sasser, BRS-SC, M-19-UFV, P. alata, P. cincinnata and P. giberti behaved as resistant, moderately resistant, moderately suscetible and susceptible, respectively. Lower percentage of plants with symtoms of Fs was found in P. mucronata, P. nitida, P. setacea, P. cincinnata and M-19-UFV In the presence of both pathogens, M-19-UFV, P. alata and P. nitida were those with larger lesion. In the presence de Fs, BRS-SC, P. alata, P. cincinnata and P. ligularis showed the largest lesions.

ABSTRACT The rational use of water while considering the increases in food production is a great challenge for agriculture currently. The aim of the present study was to evaluate the soil properties of rice paddy areas under different water management systems. For this, the rice cultivars BRS Tropical and IRGA 424 were grown under the following treatments: M1: Intermittent flooding; M2: Intermittent flooding, followed by continuous flooding; M3: Continuous flooding, followed by intermittent flooding; and M4: Continuous flooding for the entire plant cycle. As a control, a non-cultivated area, adjacent to the experimental plots was also evaluated. The variables analyzed were P, K+, Ca2+, Mg2+ and Al3+ contents, pH, soil organic carbon (SOC), total nitrogen (TN) Carbon Stock (C-Stock), nitrogen stock (N-Stock), Cation-exchange capacity (CEC), C/N ratio; CO2 emission, soil microbial biomass carbon (SMB), metabolic coefficient (qMic) and acid phosphatase and urease activities. There was not difference among the different water management systems for P, K+, Mg2+, CEC and C/N ratio. The SMB and the acid phosphatase and urease activities were lower under the different treatments when compared to the control. The CO2 emission under rice paddy system was influenced by the phenological phase of the crop. The variables SOC, C-Stock, SMB, C/N ratio, K+, acid phosphatase and usease activities are those most sensitive attributes observed in the soil under different water management systems during rice cultivation. Water management in the rice paddy system influenced soil by changing its quality.