ABSTRACT The aim of this study was to evaluate the efficiency of the porous ceramic cup extractors, associated with ion meters, for the determination of nutrients availability for bell pepper and melon crops in substrate. Substrate solution was acquired using aqueous extract 1:1.5 (v/v) and also the porous ceramic cup extractor. Electrical conductivity (EC), pH and macronutrient contents were determined for the substrate solution through analytical method. The concentrations of NO- and K+ in the solutions obtained with porous ceramic cup extractors, and the N and K contents in the diagnostic leaf for nutritional evaluation were also determined. The concentrations of NO3- and K+ using the porous ceramic cup extractors have strong correlation (r=0.96 and 0.92, respectively) with the ones obtained using the standard method, as well as a moderate correlation (r=0.65) and a strong one (r=0.71) with contents of N and K, respectively, in the melon diagnostic leaf; and a weak correlation (r=0.36 and 0.26, respectively) in the bell pepper diagnostic leaf. The use of porous ceramic cup extractors for obtaining the substrate solution and the determination of the N-NO- and K+ contents by means of specific ion meters are a fast method of evaluating nutrients availability in soilless cultures.

ABSTRACT Powdery mildew is an important disease in tomato, which requires technologies for its control. Homeopathy is a science that has been improved as an alternative method in agriculture. Thus, this study aimed to evaluate the homeopathic medicine Ferrum sulphuricum in 6, 12, 24, 48, 72 and 96CH dynamizations on powdery mildew control. The experiment was conducted from May to June 2013 in a greenhouse, in split-split- plot design, and the results were compared with the controls 30% ethanol and distilled water. We evaluated the area under disease progress curve (AUDPC), relative chlorophyll index (SPAD), influence on plant growth by volume and mass of roots, and mass of fruits and shoots and even the pathogen sporulation on leaves. For the AUDPC, all the dynamizations reduced the disease. The Santa Clara genotype showed up to 41% less and Cedro 31% less disease compared with the control ethanol, in the upper third of the plant. For the SPAD index, there was an increase of up to 322% in the middle third of the plant treated with 24CH dynamization. For the growth variables, all the dynamizations increased up to 197% the volume and weight of roots for Cedro and Santa Clara. The 6, 12, 24, 72 and 96CH dynamizations reduced the pathogen sporulation on Santa Clara tomato leaves by up to 40%. The data indicate that the medicine Ferrum sulphuricum can control powdery mildew on tomato, increase the growth of plants and that there is a differential response according to the host genotype.

ABSTRACT The objective of this work was to compare soil beetle (Coleoptera) species composition between two sites on the Borborema Plateau in Northeastern Brazil. We collected 483 individuals belonging to 23 Coleoptera families and 75 species/morphospecies. On the east face of the Borborema Plateau (Areia-PB) we collected a total of 332 individuals representing 58 species/morphospecies and 21 families. On the west face (Cabaceiras-PB) we collected 151 individuals representing 24 species/morphospecies and eight families. Among the 75 total species/morphospecies collected, 51 occurred exclusively on the eastern face of the plateau and 17 occurred exclusively on the west face. Only seven morphospecies were sampled in both areas. The marked difference in beetle assemblage species composition between the west and east sides of the Borborema Plateau suggests that the positioning and climatic variations maintain and promote high levels of beetle diversity in northeastern Brazil.

ABSTRACT The objective of this study was to evaluate the effect of combinations of nitrogen, phosphorous and potassium doses on the production components of custard-apple irrigated with saline waters. The experiment was conducted in a greenhouse, using a Neossolo Regolítico (Entisol) of clay loam texture in Campina Grande-PB, Brazil. The treatments were distributed in a randomized block design, in a 2 × 8 factorial scheme, with three replicates, corresponding to two levels of electrical conductivity of water - ECw (0.8 and 3.0 dS m-1) and eight combinations of fertilization with nitrogen, phosphorus and potassium (100-100-100; 100-100-125; 100-125-100; 100-125-125; 125-100-100; 125-100-125; 125-125-100 and 125-125-125% of the recommendation, for the third year of cultivation). The combination of 100-100-100% corresponded to 100, 60 and 60 g of N, P2O5, K2O per plant per year, respectively. High concentrations of salts in the irrigation water reduced the number of fruits, fresh fruit mass, total number of seeds and mass of seeds of custard-apple. Plants achieved the best development when grown under 125-100-100, 125-125-125 and 100-100-100% combinations of N-P-K recommendation. Irrigation with ECw of 3.0 dS m-1 associated with the 100-125-125% combination of fertilization increased the average mass and height of the custard-apple fruits.

ABSTRACT Absence of drainage associated with high evapotranspiration and irregular precipitations contributes to the accumulation of salts in the soil, reducing nutrient absorption and yield. Nutritional management is important for the crop to express its maximum production potential, and nitrogen is the macronutrient most required by the corn crop. The objective of this study was to evaluate yield and leaf contents in corn under different nitrogen fertilization recommendations and salt stress. The experiment was conducted from June to September 2019, at the University of International Integration of Afro-Brazilian Lusophony in Redenção-CE, Brazil. The experimental design used was completely randomized, in a 2 x 3 factorial arrangement, with 6 replicates, with two levels of electrical conductivity (0.3 dS m-1 and 3.0 dS m-1) and three nitrogen fertilization recommendations (0, 50 and 100% of the recommendation). The variables analyzed were unhusked ear weight, husked ear weight, yield and leaf contents of N, P, K, Ca, Mg and Na. Irrigation with saline water (3.0 dS m-1) reduces the unhusked ear weight, husked ear weight and yield. Nitrogen fertilization recommendations of 50% and 100% promoted higher values of unhusked ear weight, husked ear weight and leaf N contents, but reduced leaf P contents. The 50% and 100% recommendations promote higher yield values for the two levels of electrical conductivity studied (0.3 and 3.0 dS m-1). The 50% and 100% recommendations associated with saline water irrigation increased the leaf contents of K, Na, Mg and Ca.

ABSTRACT Bitter melon (Momordica charantia L.) is a plant species recommended by the Brazilian Health Regulatory Agency (Anvisa) as hypoglycemiant. The characterization of plants is an essential step in any breeding program. The objective of the present work was to organize and characterize a bitter melon germplasm collection, based on morpho-agronomic characters, to assess its genetic diversity and identify genotypes of agronomic interest. Eighty-eight genotypes were characterized for 38 descriptors. Redundant descriptors were identified through Principal Component Analysis (PCA); after their exclusions, a new PCA was carried out to verify the dispersion among the genotypes. Groups in the PCA were defined using the kmeans clustering method. The groups were studied for phenotype pattern using radar chart. Populational diversity was estimated through Shannon and Pielou indexes. Intra group diversity was estimated through analysis of similarity (anosim). The relative importance of variables for diversity was also estimated. Seventeen variables were redundant. The genotypes were grouped into 5 groups. Groups G1 and G5 were antagonist regarding fruit and seed productions and fruit, leaf, and seed sizes. A trend of decrease in fruit, leaf, and seed sizes was found in groups from G1 to G5. The diversity was high. Intra group diversity was high among small fruit genotypes, and low for medium-sized fruit genotypes. The variable number of male flowers (NMFL) was identified as that presented the greatest contribution to estimation of diversity. The genotypes UFRRJ MSC072, 042, 028, and 087 stood out with the highest number of fruits produced.

ABSTRACT - Based on its nutritional and economic value, the lima bean (Phaseolus lunatus L.) is the second most important species of the genus. It has high genetic diversity and potential for production and is considered an alternative food and income source. The objective of this study was to apply the restricted maximum likelihood/ best linear unbiased prediction (REML/ BLUP) methodology to estimate genetic parameters and predict genotypic values in F3 populations of lima beans. Twelve characteristics were evaluated in five populations with indeterminate growth habits (H39, H72, H53, H90, and H56). Model 83 from the Selegen program was used for analysis. Considering the genetic parameters, the highest values of genetic variance were for plant height and number of pods per plant. Pod thickness and seed width are favorable for breeding programs. Seed width selection gain was significant for populations H56 and H90 at 11.26 mm and 10.50 mm, respectively. As for the length and thickness of seeds, the gains were less significant, with population H53 showing the greatest gain. The REML/ BLUP methodology proved efficient in estimating genetic parameters and predicting gains in lima bean populations. The estimated selection gains indicated that the highest gains were obtained for plant height, the number of pods per plant, pod thickness, seed width, and the number of days to maturity. Populations H53 and H56 stood out for having large and white seeds, thus being potential populations for species improvement.

ABSTRACT Lima bean (Phaseolus lunatus) can be considered as an alternative income and food supply to farmers of the Brazilian Northeast. This crop has faced serious sanitary problems. Among the most important diseases that attack this crop, the anthracnose caused by Colletotrichum truncatum requires greater attention. This study aimed to determine the resistance of lima bean accessions to the isolates of C. truncatum. Detached leaves were used from ten lima bean accessions, originated from production fields in Paraíba State - Brazil. They were artificially inoculated with ten isolates of C. truncatum. The isolates were grown on bean-dextroseagar medium under temperature 27 ± 2 °C and a photoperiod of 12 hours, for fourteen days. The evaluations of the accessions’ resistance to the isolates were performed at 5, 7, 9, 11 and 13 days after inoculation (DAI), adopting a scale of notes, and the results were transformed in the area under the disease progress curve. The research was carried out in completely randomized design, in a 10x10 factorial arrangement (accessions x isolates) with 12 replications. The first symptoms of anthracnose on the detached leaves appeared from the third day after inoculation. The accessions were grouped from highly to moderately resistant or susceptive. The aggressiveness among C. truncatum isolates varied depending on the genetic variability of the lima bean accessions used. Accessions with significant resistance levels to anthracnose can be used as resistance sources in future breeding programs.

ABSTRACT The objective of this study was to evaluate potassium and chloride accumulation in, and the yield and quality of the potato tubers of the Asterix cultivar, under the application of two potassium fertilizer sources (KCl and K2SO4.2MgSO4) and their combinations. The experimental design was a randomized complete block with five treatments and four replications in a factorial scheme with a subdivided plot. The presence of greater than 61.8% of the recommended dose of chloride in potassium fertilization affects potato plant growth, with less dry matter accumulation in the aerial part. This does not occur in the tubers because of lower nutrient translocation to the tubers. K accumulation varies between levels depending on the companion ions of the sources. Throughout the cycle, the amount of chloride increased in the aerial parts and tubers with an increase in the percentage of KCl. The total productivity is affected by the use of a combination of potassium sources in different proportions, with a maximum yield of 41.3 t ha-1 with a combination of 64.5% KCl and 36.5% K2SO4.2MgSO4. Soluble solids did not vary with the sources at a dose of 180 kg ha-1 K2O.

ABSTRACT Lima bean is an important crop in Northeastern Brazil and a source of food and income for farmers in the region. However, there have been few genetic studies on this species, which limits the knowledge available for use in breeding programs. The objective of this study was to estimate the relationship between cycle and production traits using canonical correlation analysis and to identify traits that can be used for the indirect selection of lima bean. The experiment was conducted at the Department of Plant Science of the Universidade Federal do Piauí, Teresina, in a randomized block design with five replications, in which 11 agronomic traits from six lima bean populations in the F3 generation originating from biparental crosses were evaluated in 2019. The data were subjected to canonical correlation analysis using the virtual environment R. The results showed that only the first coefficient of the canonical pair was significant (r = 0.5531) by the quisquare test, suggesting that the studied groups were not independent, as the cycle traits showed coefficients of large magnitudes in the relationship between groups. The canonical correlation results suggested that there is a linear association between cycle and production traits in lima beans, in which days to flowering, days to maturation, pod length, seed width, and seed thickness contribute the most to the association between groups.