ABSTRACT This study aimed to validate the artificial hybridization without emasculation in lima beans, identifying F1 generation using microsatellite markers (SSR). We used four accessions from the Active Germplasm Bank of Phaseolus, Universidade Federal do Piauí (BGP-UFPI), with contrasting growth habits and days-to-maturity traits. The 241 crosses performed had a percentage of hybrid pods of 5.8%, obtaining 42 seeds in F1. Artificial cross-fertilization was confirmed by microsatellite markers (BM 211, BM 141, BM 154, and GAT 591), and four plants were identified as hybrids. Thus, the proposed method is effective in performing artificial crosses for lima beans.

ABSTRACT Handroanthus impetiginosus is a tree species with ecological and economic potential. Despite that, in the Brazilian market, its wood is heavily exploited in the illegal trade. Therefore, studies on genetic diversity are necessary in order to propose strategies for conservation of this species. Thus, the aim of this study was to select Inter Simple Sequence Repeat (ISSR) primers for genetic diversity studies applied to the forest population of H. impetiginosus. For this, 30 ISSR molecular primers were tested in 30 individuals, evaluating the total number of loci, polymorphism rate and polymorphic information content, as well as marker index and resolving power. Eight primers were selected for having a better amplification pattern, which provided 62 loci. The polymorphic information content of the primers ranged from 0.34 to 0.49, while the marker index (MI) averaged 3.20, with resolving power (RP) of 2.40, Nei’s diversity (He) of 0.35 and Shannon index (I) of 0.52. The results show that the primers UBC 807, 809, 818, 824, 857, 860, 873 and 881 are efficient for quantifying the genetic diversity of H. impetiginosus. These results can contribute to supporting strategies aimed at the conservation of this species and selection of parent trees.

ABSTRACT Family farming is important for the production of food for human consumption, but it lacks resources to invest in the soil fertility of its crops. The objective of this study was to analyze whether the use of green manures increases soil fertility in terms of the nutrients N, P and K with low environmental risk for family agricultural production. An experiment was set up in the State of Mato Grosso (Brazil), in randomized complete block design, with a 6 x 3 factorial scheme, four replications, corresponding to 6 types of plants and 3 doses of phosphorus. Leguminous green manure plants were: velvet bean, Crotalaria juncea, Crotalaria ochroleuca and dwarf pigeon pea, in addition to plots with pearl millet and weedy fallow control. Rock phosphate (i.e., reactive natural phosphate) was applied as a source of phosphorus at 0, 50 and 100 kg P2O5 ha-1. The species used as green manure were cut in full bloom and the levels of N, P, K and C in plants and soil were determined. Leguminous green manure plants, after mineralization, increased the stocks of N, P and K in the soil. Crotalaria juncea was the one that reached the highest N accumulation in its constitution, being recommended in the intercropping with species with C/N ratio > 30 to minimize risks of contamination with nitrate in the soil. This work concluded that the managements with green manure plants, especially Crotalaria ochroleuca, are recommended and environmentally safe technical alternatives for family farming.

ABSTRACT Morphoagronomic characterization is a basic requirement to identify a phenotypic profile of a population. The quantification of variability allows efficient selection of superior and divergent genotypes. Thus, this study aimed to estimate the variability among 490 genotypes and seven strains, from an F2 population of Ricinus communis L., in 35 morphoagronomic traits and 12 agronomic traits. For qualitative descriptors, the entropy technique was used in the percentage frequencies of each category, computing its level using the coefficient of Rényi (1961). Quantitative descriptors were subjected to analysis of variance by the F test, and Tukey test was performed at 1% probability level. Of the morphoagronomic traits used, 13 were related to plants, nine were related to inflorescence, six were related to fruits and seven were linked to seeds, in addition to 12 agronomic traits. The material was arranged in the field with families (strains of five families) interspersed with their respective parents (controls). Stem color, shape and number of racemes collected, main color, type of secondary color and hundred-seed weight have high variability in the population, with formation of 68 groups as a function of genetic similarity. The possibility of selection as to the number of racemes harvested is clear, so it is possible to identify genotypes with higher number, aiming to enhance crop yield.

ABSTRACT The knowledge of genetic diversity in plant population is essential to the success of plant breeding programs. Thus, previous characterization of landraces is one of the first steps before the indication of genotypes to these plant breeding programs. This study aimed to characterize, through morphological traits, and estimate the genetic diversity in landraces of lima bean (Phaseolus lunatus L.). Genetic diversity was estimated by using multivariate methods that selected individual landraces to be indicated for farmers and consumers. According to morphological traits proposed by Biodiversity International, the genotypes UFPI-667 and UFPI- 682 showed higher dissimilarity and high potential to be used in crosses since they are genetically distant and complementary. The principal component analysis identified positive and significant phenotypic associations between variables: pod length, pod width, and grain production. According to the multivariate methods used, the landraces UFPI-666, UFPI-650, UFPI-651, UFPI-687, UFPI-658, UFPI-673, UFPI-667, and UFPI-674 are potential candidates for selection since they have relevant features for lima bean breeding, such as shorter cycles and higher grain production. This study showed that multivariate analysis can be used as an effective tool to find potential traits in lima bean and can assist the lima bean breeders in the selection of potential landraces. Accessions UFPI-667 and UFPI-682 can be indicated as genitors for breeding programs, as they are genetically distant and complementary in their characteristics.

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.