Cássio Egídio Cavenaghi Prete

Molecular identification of Aspergillus spp. isolated from coffee beans

Some species belonging to the genus Aspergillus are potential producers of ochratoxin A (OA), a mycotoxin with nephrotoxic, immunosuppressive, teratogenic and carcinogenic effects. The aim of the present study was to identify the species of Aspergillus that contaminate the inside of coffee beans collected in the stage of maturation and drying, from 16 producing areas located in the northern region of the State of Parana, in the South of Brazil. A total of 108 isolates of Aspergillus spp. was identified at the species level, by sequencing the internal transcribed spacer (ITS1-5.8S-ITS2) of ribosomal DNA (rDNA). The results revealed the presence of potentially ochratoxigenic species in 82% of the geographic regions studied, among which Aspergillus niger was the species most frequently detected, followed by A. ochraceus and A. carbonarius. The presence of A. carbonarius in immature coffee fruits harvested from trees is reported for the first time.

Reliable indirect competitive ELISA used for a survey of ochratoxin A in green coffee from the North of Paraná State, Brazil.

The performance of an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) based on a monoclonal antibody (mAb) for ochratoxin A (OTA) detection was evaluated in a comparative study with high-performance liquid chromatography (HPLC) analysis using 68 freshly harvested coffee samples from the North of Paraná State, Brazil. The anti-OTA mAb showed high specificity and low cross-reactivity with OTA analogues (OTB and OTα), but cross-reacted with OTC. This ic-ELISA showed a detection limit of 3.75 ngg−1 sample, when compared to 0.80 ngg−1 by HPLC, with an ic-ELISA/HPLC correlation coefficient of 0.90. As regards OTA analysis of these coffee samples, natural contamination was detected in 10 samples (14.7%) by both methods, where the ic-ELISA values (range 3.9–7.3 ngg−1) were 1.1 to 1.6-fold higher than HPLC data (2.7–4.7 ngg−1). Five samples (7.4%) were OTA positive (range 0.84–1.30 ngg−1) only by HPLC assay, probably due to the higher detection limit reached by ic-ELISA. OTA was undetectable in 53 samples (77.9%) by both methods, while all positive samples (range 0.84–7.30 ngg−1) showed OTA levels lower than 8 ngg−1 (maximum limit recommended by the European Union). The matrix interference of green coffee was minimized by dilution of sample extracts before carrying out the ELISA assay. This mAb-based ic-ELISA can be effectively applied for OTA screening in coffee, because it is simple, sensitive and sample preparation is easy.

Genetic distance estimated by RAPD markers and its relationship with hybrid performance in maize

The objective of this work was to evaluate the genetic diversity of 16 maize inbred lines, and to determine the correlation between genetic distance and hybrid performance, using random amplified polymorphic DNA (RAPD) molecular markers. Twenty-two different random primers were used, which resulted in the amplification of 265 fragments, 237 (84.44%) of them being polymorphic. A genetic similarity matrix was created from the RAPD data, using Jaccard coefficient, and a dendrogram was constructed. Hybrid analyses were carried out using random block design and Griffing method VI for diallel crossings. The genetic associations showed five distinct heterotic groups. Correlations between genetic divergences detected by RAPD, as well as the means observed in the diallel crossings were positive and significant for plant height, ear height, prolificacy, and grain weight. The correlation of genetic divergences, detected by RAPD, and the specific combining ability between heterotic group associations, showed significance in all characteristics under study, except prolificacy. A direct relationship between genetic divergence and productivity was found in 79.2% of the 120 hybrids confirming the hypothesis that genetic divergence is directly related to the performance of hybrids and is efficient in predicting it.

Inoculant of Arbuscular Mycorrhizal Fungi (Rhizophagus clarus) Increase Yield of Soybean and Cotton under Field Conditions.

Nutrient availability is an important factor in crop production, and regular addition of chemical fertilizers is the most common practice to improve yield in agrosystems for intensive crop production. The use of some groups of microorganisms that have specific activity providing nutrients to plants is a good alternative, and arbuscular mycorrhizal fungi (AMF) enhance plant nutrition by providing especially phosphorus, improving plant growth and increasing crop production. Unfortunately, the use of AMF as an inoculant on a large scale is not yet widely used, because of several limitations in obtaining a large amount of inoculum due to several factors, such as low growth, the few species of AMF domesticated under in vitro conditions, and high competition with native AMF. The objective of this work was to test the infectivity of a Rhizophagus clarus inoculum and its effectiveness as an alternative for nutrient supply in soybean (Glycine max L.) and cotton (Gossypium hirsutum L.) when compared with conventional chemical fertilization under field conditions. The experiments were carried out in a completely randomized block design with five treatments: Fertilizer, AMF, AMF with Fertilizer, AMF with 1/2 Fertilizer, and the Control with non-inoculated and non-fertilized plants. The parameters evaluated were AMF root colonization and effect of inoculation on plant growth, nutrient absorption and yield. The results showed that AMF inoculation increased around 20 % of root colonization in both soybean and cotton; nutrients analyses in vegetal tissues showed increase of P and nitrogen content in inoculated plants, these results reflect in a higher yield. Our results showed that, AMF inoculation increase the effectiveness of fertilizer application in soybean and reduce the fertilizer dosage in cotton.

Deposição de glyphosate aplicado para controle de plantas daninhas em soja transgênica

6 RESUMO - Inumeros fatores estao envolvidos na tecnologia de aplicacao de um herbicida, sendo a deposicao correta fundamental para que o produto possa expressar sua eficiencia. Com o objetivo de avaliar a deposicao de uma solucao tracante constituida de glyphosate Roundup Ready (0,96 kg e.a. ha -1 ) + corante FDC-1 (1.500 ppm), foi conduzido um experimento em area semeada com soja transgenica e infestada com amendoim-bravo (Euphorbia heterophylla), localizada em Londrina-PR. As aplicacoes foram efetuadas em diferentes estadios de desenvolvimento da cultura, correspondendo a 17, 24, 31, 38 e 45 dias apos a emergencia da soja. Os alvos, plantas de soja, amendoim-bravo e placas na superficie do solo (linha e entrelinha), foram coletados apos pulverizacao, e a solucao tracante foi nestes depositada, posteriormente recuperada atraves de lavagem com agitacao em agua destilada. As amostras das solucoes recuperadas foram submetidas a analise, utilizando-se procedimentos espectrofotometricos, e os resultados de absorbância convertidos para concentracao em µL cm -2 e µL por planta. As frequencias acumuladas dos dados originais de deposito foram adequadamente ajustadas segundo modelo de Gompertz, apresentando elevada precisao (R 2 > 0,95). Os resultados indicaram que o deposito da calda de pulverizacao nas plantas de soja e amendoim-bravo reduziu progressivamente com o desenvolvimento da cultura e infestacao, sugerindo que a maior garantia de eficiencia de controle pode ser conseguida com aplicacoes precoces. Palavras-chave: Roundup Ready, tracante (Blue Brilhant) e soja transgenica. ABSTRACT - Several factors are involved in herbicide application technology, with correct deposition being essential to ensure product efficacy. To evaluate the deposition of a glyphosate tracer solution (RR) with an FDC-1 dye, an experiment was carried out in a transgenic soybean cultivated area, infested with wild poinsettia (Euphorbia heterophylla). Applications were carried out at different crop development stages, corresponding to 17; 24; 31; 38 and 45 days after soybean emergence. The targets, soybean plants, wild poinsettias, and Petri dishes on the soil surface, were collected after spraying and the tracer solution was later recovered by washing and stirring in distilled water. Samples of recovered solutions were submitted to spectrophotometer analysis, and the absorption data were converted in µL cm -2 and µL per plant. The accumulated frequencies of the original deposit data were adequately adjusted to the Gompertz model, showing high precision (R 2 > 0.95). The results showed that the spraying solution deposition on soybean plants and wild poinsettia reduced progressively with crop development and weed infestation, suggesting that control efficiency can be obtained with early applications.

Interação genótipo-ambiente de soja convencional e transgênica resistente a glifosato, no Estado do Paraná

Os objetivos deste trabalho foram: comparar a produtividade e a adaptacao de genotipos de soja convencional e de soja transgenica resistente ao herbicida glifosato, de diferentes grupos de maturacao, desenvolvidos pelo programa de melhoramento da Embrapa Soja para o Estado do Parana; estudar a importância relativa dos efeitos de local, ano, cultivar e suas respectivas interacoes; e verificar a possibilidade de se estratificar o Estado em regioes mais homogeneas, para reduzir o numero de locais nos ensaios de competicao de linhagens. Foram utilizados dados de produtividade de graos de ensaios regionais, no Estado do Parana, entre 2001 e 2005. O delineamento experimental utilizado foi o de blocos ao acaso. A possibilidade de se realizar a estratificacao do Estado em regioes mais homogeneas e de descarte de locais foi verificada pela significância da interacao genotipo x ambiente entre locais. Nao houve diferenca significativa de produtividade entre a soja convencional e a transgenica, independentemente do grupo de maturacao. O efeito de local foi mais importante que o efeito de ano, na composicao dos ambientes. A estratificacao do Estado do Parana em regioes nao trouxe vantagens, nos anos analisados, para os testes de linhagens; apenas os locais da regiao Sul mostraram algum grau de similaridade entre si.

Novas cultivares de acerola (Malpighia emarginata DC): UEL 3 -- Dominga, UEL 4 -- Lígia e UEL 5 -- Natália

The Caribbean cherry breeding program at Londrina State University began in 1992 with the establishment of a clone orchard from selected genotypes collected in the north of Parana state. UEL 3 -Dominga, UEL 4-Ligia, UEL 5-Natalia cultivars were selected after five assessment cycles taking in consideration earliness, yield, vitamin C fruit content, pest and disease tolerance, fruit size and appearance. UEL 3-Dominga and UEL 5-Natalia were outstanding for plant yield, vitamin C content and fruit size. The fructification of these cultivars happens from November to March in Londrina. UEL 4-Ligia cultivar was outstanding for earliness and yield. Its fructification happens from October to March in Londrina. UEL 3-Dominga cultivar presented an average fruit weight of 6,31g, vitamin C content of 2.906 and 1.250 mg/100g in unripe and ripe fruits respectively, acidity of 694.34 mg/100g and Brix of 9,2o. UEL 4-Ligia cultivar presented an average fruit weight of 7,85g, vitamin C content of 3579 and 1.458 mg/100g in unripe and ripe fruits respectively, acidity of 1110 mg/100g and Brix of 7,85o. UEL 5-Natalia cultivar presented an average fruit weight of 7,47g, vitamin C of 3.134,5 and 1.098 mg/100g in unripe and ripe fruits respectively, acidity of 725 mg/100g and Brix of 7,6o These three cultivars are indicated for planting in Parana state.

Época de dessecação de pastagem de inverno e produtividade de grãos de soja

The objective of this work was to evaluate the effect of the winter pasture burndown time on soybean grain yield and on its components. The experiment was performed in an integrated crop-livestock area, in Campo Mourao, PR, Brazil, from 2002 to 2005 cropping seasons. A experimental design in randomized complete blocks, with eight replicates, was used. The treatments consisted of burndown at 30, 20, 10 and 0 days before sowing (DAS). Evaluations were done for: pasture dry matter at the sowing day; soybean plant height; number of plants per meter; number of pods per plant; number of grain per pod; weight of one thousand grains; and soybean yield. Burndown can be performed at 0, 10, 20 and 30 DAS without any damage to soybean grain productivity. Yield components tend to adjust to decrease grain productivity variations; the reduction on the number of plants per meter is compensated by higher number of pods per plant.

Variabilidade genética e efeito do ambiente para o teor de proteína em grãos de feijão

O objetivo deste trabalho foi avaliar a variabilidade genetica, o efeito ambiental e a estabilidade para o teor de proteina em graos. Na safra da seca 2006, foram conduzidos dois experimentos, um para o grupo comercial carioca e outro para o grupo preto, em tres locais do Estado do Parana. O delineamento experimental utilizado foi o de blocos casualizados com tres repeticoes e parcelas constituidas de quatro linhas de 5 m, espacadas 0,50 m. Na maturidade fisiologica, retiraram-se amostras de 200 g de graos de cada parcela experimental; estas foram armazenadas em câmara fria ate a realizacao das analises do teor de proteina. A analise de variância conjunta revelou efeito significativo do genotipo, do ambiente e da interacao genotipo por ambiente. Estes resultados indicam a existencia de variabilidade genetica entre as cultivares e linhagens de feijao estudadas e que esses genotipos comportaram-se de maneira diferenciada nos diferentes ambientes onde foram avaliados. Os genotipos de feijao que apresentaram maiores teores medios de proteina, ampla adaptabilidade e alta estabilidade de comportamento foram: FT120, FT Soberano, Xamego e LP99-96 (grupo preto); BRS Pontal, FT Magnifico, IAC Tibata, IAPAR 81, IPR Juriti e Perola (grupo carioca).

Influence of genotype on protein and oil concentration of soybean seeds

Com o objetivo de avaliar a influencia do genotipo sobre as concentracoes de proteina e oleo, sementes imaturas das cultivares de soja CD 202 e CD 206 foram retiradas da planta mae no estadio R5, cultivadas in vitro em meio de cultura liquido por oito dias, contendo 20, 40 e 60 mM de glutamina. Depois disso, as concentracoes de oleo e proteina foram comparadas com as das sementes que continuaram seu desenvolvimento in vivo. Com a maior disponibilidade de glutamina para a semente, houve um aumento do conteudo proteico nas sementes. Quanto as concentracoes de proteina, os genotipos foram estatisticamente diferentes, levando a afirmar a sua influencia na concentracao de proteina na semente. As concentracoes de proteina e oleo foram inversamente relacionadas quando variou a concentracao de glutamina.