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Passo Fundo, Brazil

Bianchin V.,University Of Passo Fundo | Barcellos A.L.,OR Melhoramento de Sementes Ltda | Reis E.M.,PPGAgro | Turra C.,OR Melhoramento de Sementes Ltda
Summa Phytopathologica | Year: 2012

Studies on the genetic variability of Puccinia triticina in inoculum collected in Brazil started in 1941 with Vallega (20). The pioneering work in Brazil dates from 1949 (16) at "Instituto Agronômico do Sul", Ministry of Agriculture (MA), in Pelotas, Rio Grande do Sul State (RS), and continued after 1975 at Embrapa Wheat in Passo Fundo, RS. In 2002, analyses for the identification of P. triticina races continued at OR Seed breeding, simultaneously to Embrapa's program, both in Passo Fundo. The investigators involved in the identification of races in Brazil were Ady Raul da Silva in Pelotas (MA), Eliza Coelho in Pelotas (MA) and in Passo Fundo (Embrapa), Amarilis Labes Barcellos in Pelotas (MA) and in Passo Fundo (Embrapa and OR), Camila Turra in Passo Fundo (OR) and Marcia Chaves in Passo Fundo (Embrapa). From 1979 to 2010 growing season, 59 races were determined, according to the differentiation based on the expression of each Lr resistance gene. On average, one to three new races are detected per year. Research has focused on the use of vertical resistance; however, lately some institutes have searched more durable resistance, of the adult-plant type (horizontal, less race-specific). The uninterrupted monitoring of the wheat rust pathogenic population in Brazil during so many decades allowed the understanding of the evolution and virulence of races. The use of international nomenclature adopted by some programs has allowed the comparison of the fungus variability in Brazil with that in other countries, especially where frontiers are not barriers for spore transportation, confirmed by the occurrence of the same races all over one region. Source

Blum M.M.C.,University do Alto Uruguai | Reis E.M.,University Of Passo Fundo | Reis E.M.,OR Melhoramento de Sementes Ltda | Vieira F.T.,University Of Passo Fundo | Carlini R.,University Of Passo Fundo
Summa Phytopathologica | Year: 2015

In vitro experiments were conducted to assess the effects of substrate, temperature and time of exposure to temperature and photoperiod on P. pachyrhizi uredospore germination and germ tube growth. The following substrates were tested: water-agar and soybean leaf extract-agar at different leaf concentrations (0.5, 1.0, 2.0 and 4.0 g of leaves and 15g agar/L water), temperatures (10, 15, 20, 25, 30, and 35oC) and times of exposure (1, 2, 3, 4, 5, 6, 7, and 8 hours) to temperature and 12 different photoperiods. The highest germination and germ tube length was found for the soybean leaf extract agar. Maximum P. pachyrhizi uredospore germination was obtained at 21.8 and 22.3°C, and maximum germ tube growth at 21.4 and 22.1°C. The maximum uredospore germination was found at 6.4 hours exposure, while the maximum germ tube length was obtained at 7.7 h exposure. Regarding photoperiod, the maximum spore germination and the maximum uredospore germ tube length were found in the dark. Neither spore germination nor uredospore germ tube growth was completely inhibited by the exposure to continuous light. © 2015, Universidade Estadual Paulista (UNESP) . All rights reserved. Source

Oliboni R.,OR Melhoramento de Sementes Ltda | Faria M.V.,State University of the Central West | Neumann M.,State University of the Central West | Resende J.T.V.,State University of the Central West | And 3 more authors.
Semina:Ciencias Agrarias | Year: 2013

Twelve commercial maize hybrids were intercrossed in a complete diallel. These genotypes and three checks were evaluated in lattice design with three replications in the South-Central region of Parana State, in Laranjeiras do Sul, Guarapuava and Cantagalo. Data of yield of husked ear, plant height and ear height were submitted to joint diallel analysis according to Griffings method 4, i.e. only F1 were evaluated. Significant effect was found for general combining ability (GCA), specific combining ability (SCA) and interaction 'GCA x locations' for all characters. The interaction 'SCA x location' was not significant for both characters. Hybrids P30F53 and AS1575 showed positive and high estimates of GCA for yield of husked ear and high mean of yield, being interesting for the generation of populations with potential for intrapopulation breeding to obtain superior lines. The hybrids P30F44 and 2B688 are potentially indicated to generate populations for interpopulational breeding, since their high in yield of husked ears, positive GCA and SCA estimates, besides favorable estimates for ear height. Source

Avozani A.,University Of Passo Fundo | Reis E.M.,OR Melhoramento de Sementes Ltda | Tonin R.B.,University Of Passo Fundo
Summa Phytopathologica | Year: 2014

The experiment was conducted and repeated twice in a controlled environment, temperature of 25 ± 2ºC and photoperiod of 12 hours. Data on the percentage of mycelial inhibition were subjected to logarithmic regression analysis and the concentration that inhibits 50% of the mycelial growth (IC50) was calculated. Loss of sensitivity to carbendazim was observed for three fungal isolates, IC50 > 40 mg/L. Considering all five isolates, the IC50 for tebuconazole ranged from 1.89 to 2.80 mg/L, for epoxiconazol from 2.25 to 2.91, for cyproconazole from 9.21 to 20.32 mg/L, and for flutriafol from 0.77 to 2.18 mg/L. In the absence of information on the reference IC50 determined for wild isolates, the lowest values generated in our study can be used as standard to monitor the fungus sensitivity.Soybean target leaf spot, caused by the fungus Corynespora cassiicola, is controlled especially by leaf application of fungicides. In the last seasons, in the central-west region of Brazil, the disease chemical control efficiency has been low. This led to the hypothesis that the control failure could be due to the reduction or loss of the fungus sensitivity to fungicides. To clarify this fact, in vitro experiments were conducted to determine mycelial sensitivity of five C. cassiicola isolates to fungicides. Mycelial growth was assessed based on the growth of the mycelium on the culture medium, in Petri dishes. The medium potato-dextrose-agar was supplemented with the concentrations 0; 0.01; 0.1; 1; 10; 20 and 40 mg/L of the active ingredients carbendazim, cyproconazole, epoxiconazole, flutriafol and tebuconazole. © 2014, Universidade Estadual Paulista (UNESP). All rights reserved. Source

Ghissi V.C.,University Of Passo Fundo | Reis E.M.,OR Melhoramento de Sementes Ltda | Deuner C.C.,University Of Passo Fundo
Summa Phytopathologica | Year: 2014

In a survey of damages caused by soybean root rot to crops in the south of Brazil for several years, a root rot caused by Phomopsis sp has been found with increasing frequency. The primary symptoms are seen when the main root is cut longitudinally, including the death of the wood which shows white coloration and well-defined black lines that do not have a defined format. Thus, based on similarity, it has been called geographic root rot due to its aspect resembling irregular lines that separate regions on a map. In isolations, colonies and alpha spores of Phomopsis have prevailed. Pathogenicity test was done by means of inoculation in the crown of plants cultivated in a growth chamber. The geographic symptoms were reproduced in plants and the fungus Phomopsis sp. was reisolated. In soybean stems naturally infected with pod and stem blight, geographic symptoms caused by Phomopsis phaseoli are found. To the known symptoms on stems, pods and grains, that of root rot caused by P. phaseoli is now added. © 2014, Universidade Estadual Paulista (UNESP). All rights reserved. Source

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