Valdenir Queiroz Ribeiro

Adaptabilidade e estabilidade produtiva de genótipos de feijão-caupi de porte semi-ereto na Região Nordeste do Brasil

O objetivo deste trabalho foi avaliar a adaptabilidade e a estabilidade da produtividade de graos de 20 genotipos de feijao-caupi de porte semi-ereto, utilizando o modelo de efeitos aditivos principais e interacao multiplicativa. Os ensaios foram conduzidos em 16 ambientes da Regiao Nordeste do Brasil. Os efeitos de genotipos, ambientes e da interacao genotipo x ambiente, e os tres primeiros eixos da analise de componentes principais (ACP) foram significativos. Os dois primeiros eixos da ACP explicaram juntos 55,11% da soma de quadrados da interacao, correspondendo a 83,20% do padrao da interacao genotipo x ambiente. As linhagens TE-97-321G-4, EVX-92-49E e EVX-63-10E apresentaram alta adaptabilidade, mas somente a ultima foi altamente previsivel. A cultivar BRS Guariba e as linhagens EVX-92-49E e TE97-321G-4 expressam melhor potencial genetico em ambientes de alta produtividade.

Caracterização fisiológica, cultural e patogênica de diferentes isolados de Lasiodiplodia theobromae

Lasiodiplodia theobromae is responsible for diseases in several cultivated plants, causing significant losses in production, particularly among fruit trees in the Brazilian Northeast. Basic studies on this fungus are necessary to understand better the pathogen-host interactions and to trace control strategies. This work aimed to characterize eight isolates of L. theobromae from different hosts, accessing the mycelial growth, pycnidium production and fertility, morphological aspects of the colonies and pathogenicity. The isolates varied in all the characteristics studied. The culture medium of oatmeal agar provided best pycnidium production and fertility, with the isolate obtained from mango and passion fruit standing out. The culture medium of carrot agar did not provide pycnidium production. With relation to mycelial growth, V-8 juice medium was the culture medium which provided fastest mycelial growth. Coloration of the colony varied across a wide range, with white-gray coloration prevailing. As to the formation of pycnidia, it was verified that most of the isolates formed pycnidia. Assays evaluating pathogenicity by cross inoculation revealed that all isolates were pathogenic against all tested host plants.

Inter-relação entre caracteres de caupi de porte ereto e crescimento determinado

Ten characteristics were studied in 32 cowpea genotypes [Vigna unguiculata (L.)Walp.] with the objective of evaluating the association among yield and yield components. The experiment was conduced at Embrapa-Centro de Pesquisa Agropecuaria do Meio-Norte in Teresina, PI, Brazil. Acomplete random blocks design with six replications was used. The data were collected from the two central rows subtracting two hills at the extremities. Initial flowering and 100-seed weight, that presented the highest direct effect and positive correlation with grain yield, were the most important characters in the process of indirect selection to obtain an efficient correlated response on grain yield. However, selection for the characters angle insertion of the secondary branches and number of grains per pod had no significant direct influence on grain yield.

Cowpea protein reduces LDL-cholesterol and apolipoprotein B concentrations, but does not improve biomarkers of inflammation or endothelial dysfunction in adults with moderate hypercholesterolemia

INTRODUCTION The risks of cardiovascular diseases, the leading cause of death in the world, can be reduced by diet. Cowpea protein has been shown to significantly reduce total cholesterol, LDL-cholesterol, and liver steatosis in hamsters. OBJECTIVE The objective of this proof-of-concept study was to verify whether the consumption of cowpea protein improves lipid profile and biomarkers of inflammation and endothelial dysfunction in adults with moderate hypercholesterolemia. METHODS In a randomized, double-blind, crossover design, 38 hypercholesterolemic subjects (LDL-cholesterol = 182.5 ± 2.7 mg/dL) consumed 25 g/day of cowpea protein isolate or 25 g/day of casein (control group) for 6 weeks each, separated by a 4-week washout interval. Fasting blood samples were collected at baseline and at the end of each diet period. Lipids (total cholesterol, LDL-cholesterol, triglycerides, HDL-cholesterol) were determined by enzymatic methods, apolipoproteins (apoA-I and apoB) by standardized immunoassays, inflammatory biomarkers (C-reactive protein) by turbidimetry, and biomarkers of endothelial dysfunction (intercellular adhesion molecule 1 and vascular cell adhesion molecule 1) by enzyme-linked immunosorbent assays. RESULTS AND DISCUSSION Consumption of cowpea protein significantly reduced total cholesterol ( 12 %), LDL cholesterol ( 18.9 %), non HDL-cholesterol ( 16 %) and apoB ( 14 %), and increased HDL cholesterol (+2.7 %). No significant differences between treatment groups were observed for any of the serum inflammatory or endothelial dysfunction biomarkers. CONCLUSION The present findings demonstrated the favorable effect of cowpea protein consumption on proatherogenic serum lipids and apoB in subjects with moderate hypercholesterolemia, similar to what was observed in a previous studies on animals.

Estoques de C e de N e produtividade do milho sob sistemas de preparo e adubação nitrogenada em um Latossolo Vermelho-Amarelo do cerrado piauiense

Total soil organic carbon (C) and nitrogen (N) stocks and crop yield are influenced by tillage, biomass input from crop and nitrogen fertilization. This research aimed to evaluate the effect of different tillage systems associated to nitrogen doses on corn yield and C and N stocks in the Red Yellow Latosol in savanna of Piaui state, Brazil. The experiment was carried out in Baixa Grande do Ribeiro, south of Piaui state. The treatments were distributed in a randomized complete blocks and factor arrange 2x5, two tillage systems (no-tillage (NT) and conventional (CT)) and five nitrogen doses (0, 60, 120,180 and 240kg ha-1 N), respectively, with six replications. The corn grain yield (GY) and C and N inputs were measured and C and N soil stocks were evaluated in the 0-5, 5-10, 10-20 and 20-40cm. N doses caused a quadratic response in the grain yield, C and N inputs from maize crop and soil C stocks in both tillage systems. Higher GY were obtained by 138 and 134kg N ha-1 to CT and NT, respectively. Higher C and N inputs were obtained by 140 and 175kg N ha-1, in the CT and by 139 and 100kg N ha-1 in the NT system, respectively. Nitrogen fertilization increased soil C stocks in the NT comparing to CT in the 0-5 and 5-10 depths. No tillage adoption combined with balanced nitrogen fertilization can be important to soil organic matter production in soils under cerrado of Piaui state.

Adaptabilidade e estabilidade produtiva de feijão-caupi

ABSTRACT The objective of this work was to evaluate thegrain yield stability and adaptability of 15 cowpea ( Vignaunguiculata ) genotypes using the additive main effectsand multiplicative interaction model. The trials werecarried out at 13 environments of Piaui and Maranhao,Brazil, from 1999 to 2001. Genotype showed low effect,but environment, genotype x environment interaction, andthe first tree axes of the principal components analysiswere highly significant (P<0.01). The principalcomponents analysis explained 72.82% of the sum ofsquares of the genotype x environment interaction. Evx91-2E and Evx 63-4E genotypes showed high adaptabilityand stability and can be cultivated in all environments.Evx 47-6E and Evx 92-49E genotypes were adapted tolow yield environments, while Evx 63 - 10E genotype hadthe highest yield averages, and specific adaptation tohigh quality environments. Brejo, MA, 2001, and BomJesus, PI, 2000 environments were the most previsionalones, while Teresina, PI, 2001, and Baixa Grande doRibeiro, PI, 2001, were higly unstables. The genotype xenvironment interaction is variable inside andhomogeneous between the states of Piaui and Maranhaoin terms of environmental quality.

Potencial genético de progênies de feijão-caupi segregantes quanto ao tipo da inflorescência

The objective of this work was to evaluate the genetic yield potential of segregating cowpea progenies regarding inflorescence type. Sixty-eight F4 progenies obtained from the backcrosses (TV x 5058-09C x Curly-purple) x TV x 5058-09C, and (AU94-MOB-816 x Curly-purple) x AU94-MOB-816, with parents, were evaluated. Two experiments were carried out in a randomized complete block design with 17 progenies and four replicates, in a split-plot arrangement regarding inflorescence: simple and composite. The statistical analysis was carried out by mixed models via REML/BLUP procedure. The estimates of genetic variance were significant for all evaluated traits. The traits peduncle length, average number of pods per peduncle, and initial flowering showed high variability and expression of the composite inflorescence genetic component. Progenies with simple inflorescence show similar genetic yield potential to the progenies with composite inflorescence. The progenies resulting from the backcrosses (AU94-MOB-816 x Curly-purple) x AU94-MOB-816 are promising as a strategy to increase the current levels of grain yield in cowpea.

Reação de genótipos de feijão-caupi revela resistência às coinfecções pelo Cucumber mosaic virus, Cowpea aphid-borne mosaic virus e Cowpea severe mosaic virus

Many factors can affect the yield of cowpea, especially viruses. The main species of viruses infecting cowpea in Brazil are Cucumber mosaic virus (CMV), Cowpea aphid-borne mosaic virus (CABMV), Cowpea severe mosaic virus (CPSMV) and Cowpea golden mosaic virus (CPGMV). This study aimed to evaluate the reaction of cowpea genotypes for resistance to CMV in single or in co-infections (CMV+CABMV, CMV+CPSMV-I and CMV+CABMV+CPSMV-I), which was accomplished in two steps. Firstly, 57 genotypes were evaluated in four evaluations: three in aphid proof cages with infection under controlled conditions, and one in field-grown plants under natural infection. To perform the second step, we selected 18 genotypes to be conducted in nine trials, with eight under aphid proof cages control infection, and one under natural infection. The qualitative and quantitative effects resulting from infections were evaluated. In the field trial, we assessed the number of asymptomatic plants, pod length, number of grains per pod, 100-grain mass and yield. Mixed infections reduced the plant height and dry weight, and premature death of some genotypes was observed in infections involving the three viruses. The genotypes BR17-Gurgueia, Epace V-96, TE97-309G-9, TE97-309G-22, TE97-309G-24 and Patativa showed the best behavior in relation to the mixed viral infections, presenting seeds with appropriate commercial standard and with potential for using in breeding programs.

Produtividade de grãos verdes do feijão-caupi sob diferentes regimes hídricos

The objective of this study was to evaluate green grain yield, production components and water use efficiency for cowpea-bean under different water regimes. The experiment was carried out at Embrapa Meio-Norte, in Teresina, PI, Brazil, from September to November 2009. Five irrigation blades, based on reference evapotranspiration fractions (25, 50, 75, 100, and 125% of ETo), and the evaluated cowpea-ben cultivars were BRS Guariba and BRS Paraguacu.Irrigation was performed by conventional fixed sprinkling system. The experimental designwas a randomized complete blockwith four replicates, in a split-plot arrangement (cultivars). Maximum green grain yields achieved 2,937.3 kg ha-1 for BRS Guariba and 2,492.9 kg ha-1 for BRS Paraguacu; these productivities were obtained under 354 mm and 423 mm irrigation blade, respectively. The irrigation blades of 275 mm and 231 mm for BRS Guariba and BRS Paraguacu cultivars, respectively, accomplished the most efficiency in water use for green grain yield. BRS Guariba shows a better performance compared with BRS Paraguacu.

Path analysis of iron and zinc contents and others traits in cowpea

The objective of this study was to estimate the direct and indirect effects of agronomic and culinary traits on iron and zinc contents in 11 cowpea populations. Correlations between traits were estimated and decomposed into direct and indirect effects using path analysis. For the study populations, breeding for larger grain size, higher number of grains per pod, grain yield, reduced cooking time, and number of days to flowering can lead to decreases in the levels of iron and zinc in the grain. Genetic gains for the iron content can be obtained by direct selection for protein content by indirect effects on the number of grains per pod, 100-grain weight and grain yield. The positive direct effect of grain size and protein content on the zinc content indicates the possibility of simultaneous gain by combined selection of these traits.