OR Melhoramento de Sementes Ltda

Passo Fundo, Brazil

OR Melhoramento de Sementes Ltda

Passo Fundo, Brazil
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Turra C.,OR Melhoramento de Sementes Ltda | Turra C.,University Of Passo Fundo | Reis E.M.,University Of Passo Fundo | Barcellos A.L.,OR Melhoramento de Sementes Ltda
Summa Phytopathologica | Year: 2017

Wheat leaf rust caused by the fungus Puccinia triticina may lead to damage of up to 62%. This study aimed to test the effect of different uredospore concentrations on the infectious process of four physiological races. The races MFJ-MN, MFT-MT 4002 S, TPT-HT and TDP-HT were inoculated, when the first leaf was expanded in the seedling stage, on cultivars Ônix, Abalone, Morocco and Quartzo, respectively. The tested concentrations were 0.0; 5 x 103; 10 x 103; 20 x 103 and 40 x 103 uredospores/mL mineral oil (Soltrol). After inoculation, seedlings were kept in a growth chamber at 20°C ± 2, near 100% humidity, in the dark, for 20 hours. Fifteen days after inoculation, the density of uredia/leaf was evaluated. The concentration of 40 x 103 uredospores/mL resulted in a disease intensity that allows safe differentiation between susceptible and resistant cultivars in the seedling stage, without causing leaf senescence due to high uredinium density. © 2017, Universidade Estadual Paulista (UNESP). All rights reserved.


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.


Reis E.M.,University Of Passo Fundo | Reis E.M.,OR Melhoramento de sementes Ltda | Zanatta M.,University Of Passo Fundo | Carmona M.,University of Buenos Aires | Menten J.O.M.,University of Sao Paulo
Summa Phytopathologica | Year: 2015

Published data containing fungicide concentrations that control 50% (IC50) of a given fungus were analyzed. In the analysis we considered: (i) the IC50 determined in vitro and in vivo for a given fungicide and for a specific fungus; (ii) the concentration (g/ha) of active ingredient for the fungicide indicated to control a specific disease in the field; (iii) water volume of 120/L used in the spray; (iv) the fungicide a.i. concentration (mg/L) in 120 L volume; (v) and the ratio of the concentration used in the field with that determined in the laboratory. The analysis were performed by using IC50 data for DMIs, QoIs, a carbamate and a benzimidazol against the following fungi Bipolaris sorokiniana, Drechslera tritici-repentis, D. siccans, Fusarium graminearum, Puccinia triticina, Exserohilum turcicum, Phakopsora pachyrhizi and Corynespora cassiicola. The fungicide concentrations sprayed in the field were 33.9 (D. siccans and trifloxystrobin) to 500,000.0 (E. turcicum and iprodione) times higher than that determined in the laboratory. It was concluded that the IC50 was not related to the concentration used in the field and therefore should be used to compare the power among fungicides and to monitor the fungal sensitivity shift towards fungicides. © 2015 Universidade Estadual Paulista (UNESP). All rights reserved.


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.


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.


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.


Turra C.,OR Melhoramento de Sementes Ltda | Turra C.,University Of Passo Fundo | Reis E.M.,University Of Passo Fundo | Barcellos A.L.,OR Melhoramento de Sementes Ltda
Summa Phytopathologica | Year: 2014

The method of preserving detached wheat leaves in Petri dish was used for the inoculation and development of the fungus Puccinia triticina, the causal agent of wheat leaf rust. The reaction of 26 wheat cultivars was compared by using seedlings cultivated in pots (in vivo) and detached leaves (in vitro) inoculated with four physiological races of the pathogen. After inoculation, the material was kept in a growth chamber for 15 days. The reaction was evaluated on the 15thday after inoculation. Results for each race in the evaluated genotypes confirmed the efficiency of the detached leaf method in assessing the reaction of wheat cultivars. © 2014, Universidade Estadual Paulista (UNESP). All rights reserved.


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.


Camera J.N.,University Of Passo Fundo | Deuner C.C.,University Of Passo Fundo | Danelli A.L.D.,University Of Passo Fundo | Reis E.M.,OR Melhoramento de Sementes Ltda.
Semina:Ciencias Agrarias | Year: 2014

The leaf "frog-eye" spot is a disease that often occurs in Argentina and Brazil is becoming important in soy producing regions. The difficulty in achieving inoculum for studies with P. sojina led to the development of this work was to determine the sporulation of races P. sojina in different culture media and light regimes and check difference in sporulation of races of this fungus. The plates with the culture media BDA, STT , AI , V8 and FAA containing the three races of P. sojina were subjected to a photoperiod of 12/12 h (light and dark) and continuous dark. The experimental design was a factorial 5x2x3 (culture medium, light regimes, races of P. sojina) with four replications. The greatest number of conidia cm- 2 of the fungus was found for race 23 in the middle of STT culture and races 24 e 25 in the middle of V8 culture. The fungus race 25, with the largest number of conidia cm-2, regardless of the medium and the light regimen. With respect to light regime for all races of the fungus, the largest esporulation were checked at a photoperiod of 12/12 h. When the fungus was grown in culture medium AI, this had the largest area of the colony, regardless of breed fungus and light regime.


Carmona M.,University of Buenos Aires | Sautua F.,University of Buenos Aires | Perelman S.,University of Buenos Aires | Gally M.,University of Buenos Aires | Reis E.M.,OR Melhoramento de Sementes Ltda
Crop Protection | Year: 2015

The use of foliar fungicides is a common disease control practice among soybean producers around the world, yet there is still no clear understanding about the timing and opportunity of fungicide applications to manage late season diseases (LSD) in soybean crops. The unnecessary use of fungicides in extended areas increases production costs, risk of resistance and risk of negative environmental impact. The objective of this study was to develop and validate a scoring system to guide the application of fungicides in soybean crops to manage LSDs in Argentina, with special reference to Septoria brown spot and Cercospora leaf blight. To develop the scoring system, a risk matrix with weighted epidemiological risk factors was developed based on previous research data. The scoring system recommends application of foliar fungicides based on the total points accumulated from the risk factors. Scoring greater than 33 indicates a higher probability of obtaining a positive yield response, whereas scoring below 23 indicates no expected response and thus no need for fungicide applications. Intermediate values indicate that the application of fungicides would produce uncertain results thus detailed analysis of risk factors would be required. To validate the scoring system, 19 field trials were carried out over five growing seasons in three Argentinian provinces. The fungicide used in all trials was a mixture of a quinone outside inhibitor and a demethylation inhibitor fungicide. In most cases, the scoring system resulted in appropriate decisions to apply the fungicide within the so-called "window of opportunity", which lies between the R3 and R5 soybean developmental stages. The greatest yield responses were achieved when the scoring system recommended the fungicide application at R3 or R4 or R5, depending on the obtained sum of points. In all cases, except when the scoring system recommended no application of the fungicide, disease severity values were significantly greater in untreated than in treated plants. Regarding net income, phenology-based applications showed negative margins in cases where the scoring system recommended no applications, demonstrating that in such situations the use of fungicide caused losses rather than yield advantages. In contrast, when the scoring system recommended the application of fungicide regardless of timing (R3, R4 or R5), net margins were always positive and generally provided a higher income. The scoring system presented in this study can be a valuable tool to reduce the number of fungicide applications in soybean crops, especially in seasons when conditions for LSD development are not favorable. © 2015 Elsevier Ltd.

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