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Piracicaba, Brazil

A greenhouse experiment was installed with bait cultures to extract the AMF species present in a rhizosphere soil sample of a native Araucaria angustifolia forest in Campos do Jordão, Brazil. The experimental design was completely randomized, with four increasing phosphorus doses (0, 20, 50, and 150 mg kg-1, as triple superphosphate), with five replicates, the bait plant was araucaria, and all pots were inoculated with 100 g of rhizospheric soil collected in an araucaria forest. After twelve months the spores were extracted, counted and identified, and the percent root colonization was also determined. When taking all four P doses into account, eleven AMF species could be identified: Acaulospora bireticulata, Acaulospora morrowiae, Acaulospora sp., Entrophospora colombiana, Gigaspora margarita, Glomus diaphanum, Glomus etunicatum, Glomus macrocarpum, Scutellospora calospora, Scutellospora gilmorei, and Scutellospora pellucida. There was no effect of the P dose on the total amount of spores neither on the percent root colonization. However, the correspondence analysis showed that the different AMF species were selectively associated mostly to either one or another P dose. Source

Vitti A.C.,Polo Regional Centro Sul | Trivelin P.C.O.,University of Sao Paulo | Ferreira D.A.,University of Sao Paulo | Otto R.,University of Sao Paulo | Fortes C.,University of Sao Paulo
Pesquisa Agropecuaria Brasileira | Year: 2011

The objective of this work was to evaluate the recovery, by plant cane, of the nitrogen ( 15N) from urea and from sugarcane (Saccharum spp.) crop residues - straw and root system - incorporated into the soil. The experiment was settled in 2005/2006 with the sugarcane cultivar SP81 3250. At planting, microplots of 2 m length and 1.5 m width were installed, and N applications were done with 80 kg ha -1 N (urea with 5.05% in 15N atoms) and 14 Mg ha -1 crop residues - 9 Mg ha -1 of sugarcane straw (SS) and 5 Mg ha -1 of root system (RS), labeled with 15N (1.07 and 0.81% in 15N atoms, respectively). The total N accumulation by plants was determined during the crop cycle. Although the N use by shoot from crop residue mineralization (PA and SR) increased significantly over time, this source hardly contributed to crop nutrition. The recovery of the 15N-urea, 15N-SS and 15N-RS by plant cane was 30.3±3.7%, 13.9±4.5% and 6.4±0.9%, respectively, representing 15.9, 4.7 and 1.4% of total nitrogen uptake by shoot. Source

Ronque M.U.V.,University of Campinas | Azevedo-Silva M.,University of Campinas | Mori G.M.,University of Campinas | Mori G.M.,Polo Regional Centro Sul | And 2 more authors.
Zoological Journal of the Linnean Society | Year: 2016

The closely related Camponotus renggeri and Camponotus rufipes (subgenus Myrmothrix) often live in sympatry in the Brazilian 'cerrado' savannah, and are distinguished by nuances in their blackish body colour and by the colour of the legs. Variation in morphological characters, however, makes species separation difficult and it has been suggested that the two species should be merged into one. As appropriate species identification is essential for studies in ecology and evolutionary biology, here we examine how natural history data (habitat preference, nesting biology) and molecular tools (nuclear and mitochondrial markers) perform in distinguishing sympatric populations of C.renggeri and C.rufipes. In our study area, C.rufipes was only seen in cerrado sensu stricto (scrub of shrubs and trees), whereas C.renggeri occurred in cerrado sensu stricto and cerradão (closed woodland). Camponotus renggeri nested underground or in fallen/erect dead trunks, whereas C.rufipes constructed distinctive nests of dry straw. Nest persistence through time was higher in C.rufipes, especially in the hot/rainy season. Nest distribution was random in C.renggeri and aggregated in C.rufipes. Molecular data consistently showed that, regardless of the source of genetic variation, the uppermost hierarchical level of divergence is observed between species, unambiguously differentiating the individuals identified as C.renggeri and C.rufipes as two independent evolutionary lineages. Mitochondrial data throughout the species' geographical ranges further confirmed a consistent genetic divergence between C.renggeri and C.rufipes along their distribution in Brazil. Our integrated approach combining morphological traits with natural history and molecular data confirms that C.renggeri and C.rufipes are valid species that can be separated in our study area relatively well. © 2016 The Linnean Society of London. Source

Cidade F.W.,University of Campinas | Vigna B.B.Z.,Brazilian Agricultural Research Corporation Embrapa Southeast Livestock | de Souza F.H.D.,Brazilian Agricultural Research Corporation Embrapa Southeast Livestock | Valls J.F.M.,Embrapa Genetic Resources and Biotechnology | And 4 more authors.
BMC Genetics | Year: 2013

Background: Paspalum (Poaceae) is an important genus of the tribe Paniceae, which includes several species of economic importance for foraging, turf and ornamental purposes, and has a complex taxonomical classification. Because of the widespread interest in several species of this genus, many accessions have been conserved in germplasm banks and distributed throughout various countries around the world, mainly for the purposes of cultivar development and cytogenetic studies. Correct identification of germplasms and quantification of their variability are necessary for the proper development of conservation and breeding programs. Evaluation of microsatellite markers in different species of Paspalum conserved in a germplasm bank allowed assessment of the genetic differences among them and assisted in their proper botanical classification.Results: Seventeen new polymorphic microsatellites were developed for Paspalum atratum Swallen and Paspalum notatum Flüggé, twelve of which were transferred to 35 Paspalum species and used to evaluate their variability. Variable degrees of polymorphism were observed within the species. Based on distance-based methods and a Bayesian clustering approach, the accessions were divided into three main species groups, two of which corresponded to the previously described Plicatula and Notata Paspalum groups. In more accurate analyses of P. notatum accessions, the genetic variation that was evaluated used thirty simple sequence repeat (SSR) loci and revealed seven distinct genetic groups and a correspondence of these groups to the three botanical varieties of the species (P. notatum var. notatum, P. notatum var. saurae and P. notatum var. latiflorum).Conclusions: The molecular genetic approach employed in this study was able to distinguish many of the different taxa examined, except for species that belong to the Plicatula group, which has historically been recognized as a highly complex group. Our molecular genetic approach represents a valuable tool for species identification in the initial assessment of germplasm as well as for characterization, conservation and successful species hybridization. © 2013 Cidade et al.; licensee BioMed Central Ltd. Source

Siqueira M.V.B.M.,University of Sao Paulo | Marconi T.G.,University of Campinas | Bonatelli M.L.,University of Sao Paulo | Zucchi M.I.,Polo Regional Centro Sul | Veasey E.A.,University of Sao Paulo
American Journal of Botany | Year: 2011

Premise of the study: Dioscorea alata L. is one of the most widely distributed species of the genus in the humid and semihumid tropics and is associated with traditional agriculture. Only a few microsatellite markers have been developed so far for this and other Dioscorea species. Methods and Results: We isolated 14 codominant polymorphic microsatellite markers using a microsatellite-enriched genomic library technique. Ten microsatellite loci were selected, and 80 D. alata accessions from different regions in Brazil were evaluated with nine polymorphic loci. The polymorphism information content (PIC) varied from 0.39 to 0.78 and the power discrimination (PD) ranged from 0.15 to 0.91. Six of the markers showed transferability for the species D. bulbifera, D. cayenensis-D. rotundata, and D. trifida. Conclusions: The SSR markers obtained are an important tool for further studies aiming to characterize the genetic diversity in D. alata and other Dioscorea spp. accessions. © 2011 Botanical Society of America. Source

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