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Silva R.R.,Federal Technological University of Parana | Benin G.,Federal Technological University of Parana | Marchese J.A.,Federal Technological University of Parana | da Silva E.D.B.,Federal University of Santa Maria | Marchioro V.S.,Cooperativa Central de Pesquisa Agricola
Acta Scientiarum - Agronomy | Year: 2014

The potential yield of wheat is mainly determined by temperature, solar radiation and the photothermal quotient. The objective of this study was to determine the temporal and spatial variability of the photothermal quotient and the frost risk to identify suitable sowing dates for wheat in Parana State, Brazil. The results showed that the photothermal quotient has greater spatial variability than temporal variability. The sowing date affects crop conditions that can in turn affect yield. However, the photothermal quotient and frost risk fluctuate differently in different Value for Cultivation and Use (VCU) regions. The regions VCU 1 and VCU 2 showed greater temporal variability of the photothermal quotient. The photothermal quotient ranged from 1.5 to 2.0 MJ m-2 day °C in VCU 1, from 1.1 to 1.5 MJ m-2 day °C in VCU 2 and from 1.0 to 1.2 MJ m-2 day °C in VCU 3. Sowing performed in June provided the greatest photothermal quotient in all VCU regions. However, June sowing increased the frost risk in VCU 1. Thus, the sowing date can be used as a management tool for the attainment of higher yield in wheat. Source

Vieira E.S.N.,Cooperativa Central de Pesquisa Agricola | von Pinho E.V.R.,Federal University of Lavras | Carvalho M.G.G.,Federal University of Lavras | Esselink D.G.,Plant Research International | Vosman B.,Plant Research International
Genetics and Molecular Biology | Year: 2010

Microsatellite markers, also known as SSRs (Simple Sequence Repeats), have proved to be excellent tools for identifying variety and determining genetic relationships. A set of 127 SSR markers was used to analyze genetic similarity in twenty five Coffea arabica varieties. These were composed of nineteen commercially important Brazilians and six interspecific hybrids of Coffea arabica, Coffea canephora and Coffea liberica. The set used comprised 52 newly developed SSR markers derived from microsatellite enriched libraries, 56 designed on the basis of coffee SSR sequences available from public databases, 6 already published, and 13 universal chloroplast microsatellite markers. Only 22 were polymorphic, these detecting 2-7 alleles per marker, an average of 2.5. Based on the banding patterns generated by polymorphic SSR loci, the set of twenty-five coffee varieties were clustered into two main groups, one composed of only Brazilian varieties, and the other of interspecific hybrids, with a few Brazilians. Color mutants could not be separated. Clustering was in accordance with material genealogy thereby revealing high similarity. © 2010, Sociedade Brasileira de Genética. Source

Dranski J.A.L.,Cooperativa Central de Pesquisa Agricola | Malavasi U.C.,West Parana State University | Malavasi M.M.,West Parana State University | Jacobs D.F.,PurdueUniversity
Revista Arvore | Year: 2013

Immediately after planting, tree seedlings face adverse environmental and biotic stresses that must be overcome to ensure survival and to yield a desirable growth. Hardening practices in the nursery may help improve seedling stress resistance through reduction of aboveground plant tissues and increased root volume and biomass. We conducted an assay to quantify changes in the morphogenesis following application of ethephon on seedlings of Pachystroma longifolium (Ness) I. M. Johnst.during hardening. The results showed no effect of the ethephon treatments on the number of leaves but a reduction of up to 50% in seedling height increment, and an increase in stem diameter increment of up to 44% with the 600 mg L-1ethephon treatment, which consequently altered seedling Dickson Quality Index. Our results indicate that ethephon may help to promote desired morphological changes that occur during seedling hardening in nurseries. Source

Nasu E.G.C.,West Parana State University | Pires E.,Cooperativa Central de Pesquisa Agricola | Formentini H.M.,West Parana State University | Furlanetto C.,University of Brasilia
Tropical Plant Pathology | Year: 2010

The aim of this work was to study the nematicidal effect of manipueira on the control of Meloidogyne incognita. In vitro tests were split into two completely randomized assays: 1. manipueira 100%, 75%, 50% and 25% in 12 replications; 2. manipueira 15%, 10%, 8%, 6%, 4% and 2% in 5 replications. The pot assay followed a completely randomized design with the treatments manipueira 10%, 25% and 50% in 5 replications. For both assays the positive control was water and the negative control was the nematicide Carbofuran (50 mg.L-1 of active ingredient (a.i.) or 2 g of commercial product/pot). For in vitro assays the variables assessed were live or dead nematodes and number of galls on inoculated plants. For the pot assay the variables evaluated were plant height, root length, number of galls, number of eggs and reproduction factor (RF). The in vitro results indicated that only the manipueira treatments from 100% to 10% dilution showed maximum control. The pot assay demonstrated that the treatment manipueira 50% caused better development of tomato shoots than the others. However, manipueira 10% and 25% were more effective against of M. incognita in pots. Source

de Paula M.F.B.,Federal University of Vicosa | Sagio S.A.,Federal University of Lavras | Lazzari F.,Cooperativa Central de Pesquisa Agricola | Barreto H.G.,Federal University of Lavras | And 2 more authors.
Coffee Science | Year: 2012

In order to use sensitive techniques of molecular biology, such as the study of differentially expressed genes, a highquality RNA in suitable quantities is necessary. Due to the presence of several varieties and often expressive quantities of secondary compounds in plants, there is no standard method for the isolation of nucleic acids that can be used for all species. Polyphenols and polysaccharides are the compounds that interfere the most in the extraction process, and when they are present, a low-quality RNA is produced. Four RNA extraction methods (CTAB method, Hot Borate, CONCERT and Tri Reagent), in four different coffee tissues (root, leaf, flower and fruit) were tested in this work, aiming at determining which method is more efficient. It was observed that the CTAB and Hot Borate methods, in which PVP and/or β-mercaptoethanol were added and precipitation with LiCl was performed, presented more pure RNA, with no degradation observed in any of the tissues, being suitable for further gene expression analysis. High-quality RNA was not obtained from any tissue in the extraction with Tri Reagent, which includes the use of phenol, and thus expression analysis was disturbed. The CTAB macro extraction method presented samples with the highest RNA quality and largest quantities in all tissues. Future works need to be carried out aiming the standardization of this macro extraction method. Source

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