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Borges L.M.F.,Federal University of Goais | Duarte S.C.,Federal University of Goais | Louly C.C.B.,Instituto Federal Goiano IF Goiano
Ciencia Rural | Year: 2015

Although Rhipicephalus microplus mainly parasitizes bovines, different breeds can have variable parasite burdens, with indian breeds being less susceptible to tick infestation than european breeds. These ticks use pasture questing to seek out their hosts in the open spaces of their grassland habitats. Using an olfactometer bioassay, where the larva could express questing, the authors aimed to answer whether R. microplus exhibit different behaviors depending on the bovine breed. Sixteen larvae were individually exposed to the odors of five holstein friesian cattle, five nelore cattle, hexane (negative control) and 2-nitrophenol (positive control). The highest questing responses were observed to 2-nitrophenol and holstein odors. The lowest response was observed to the solvent and was statistically similar to nelore odors. It is possible to conclude that R. microplus express different questing behaviors depending on the odor of the breed perceived. This behavior can help R. microplus to avoid parasitizing nelore bovines and is biologically advantageous for the tick because it is known that ticks that feed on this host have impaired development. © 2015, Universidade Federal de Santa Maria. All rights reserved.

Silva R.V.,Federal University of Vicosa | Silva R.V.,Instituto Federal Goiano IF Goiano | de Lima Oliveira R.D.,Federal University of Vicosa | da Silva Ferreira P.,Federal University of Vicosa | And 2 more authors.
Bragantia | Year: 2015

Considering that the root-knot nematode Meloidogyne exigua has caused great yield losses to cofee production in Brazil, this study aimed to determine whether the penetration and the reproduction events of this nematode on the roots of plants from two cofee cultivars with diferent levels of basal resistance to this nematode could be afected by silicon (Si). Cofee plants from the cultivars Catuaí and IAPAR 59, which are susceptible and resistant, respectively, to M. exigua, were grown in pots containing Si-deficient soil that was amended with either calcium silicate (+Si) or calcium carbonate (–Si). The Si concentration on the root tissue significantly increased by 159 and 97% for the +Si plants from the cultivars Catuaí and IAPAR 59, respectively, compared to the –Si plants of these cultivars. The population of M. exigua, the number of galls and the number of eggs were significantly reduced on the roots of the +Si plants of the cultivars Catuaí and IAPAR 59 compared to the –Si plants of these cultivars. It was concluded that the development and reproduction events of M. exigua were negatively impacted on the roots of cofee plants supplied with Si. © 2015, Instituto Agronomico. All rights reserved.

Costa R.R.G.F.,State University of Goias | Quirino G.S.F.,State University of Goias | Naves D.C.F.,State University of Goias | Santos C.B.,Instituto Federal Goiano IF Goiano | Rocha A.F.S.,State University of Goias
Pesquisa Agropecuaria Tropical | Year: 2015

The misuse of fertilizers has become a growing concern in terms of agricultural and environmental sustainability. One alternative to reduce the impact of chemical fertilizers is the use of inoculants containing nitrogen-fixing and plant growth promoting bacteria. This study aimed at evaluating the effects of an inoculant with Azospirillum brasilense on the growth and yield of secondharvest maize. The experimental design was randomized blocks with three replications, in a 3 × 5 factorial scheme. The treatments consisted of three inoculation methods (control without inoculation, seed inoculation and leaf-sprayed inoculation at the V4 stage) and five cover N-fertilization doses (0%, 25%, 50%, 75% and 100%, with the 100% dose corresponding to 50 kg ha-1 of N as urea). Inoculated plants showed a greater growth for height (9.5% and 16%), stem dry biomass (49% and 6.75%) and root dry biomass (123% and 97%), respectively for seed inoculation and spraying, as well as increases in ear size (8%), chlorophyll content (4%), 1,000-grain weight (12%) and grain yield (29%), when compared to non-inoculated plants. The effects of N doses were only significant for 1,000-grain weight and grain yield (kg ha-1), with seed inoculation providing a higher yield for second-harvest maize. © 2015, Universidade Federal De Goias (UFG). All rights reserved.

Moreto J.A.,Instituto Federal Goiano IF Goiano | Junior F.A.P.,Empresa Brasileira de Aeronautica EMBRAER S.A | MacIel C.I.S.,University of Sao Paulo | Bonazzi L.H.C.,University of Sao Paulo | And 3 more authors.
Materials Research | Year: 2015

The aim of this study was to evaluate and compare the effect of low temperature and saline environment on the fatigue crack growth behavior of the AA7050-T7451 Al alloy and the recently developed AA2050-T Al-Cu-Li alloy. Fatigue at room and low temperature and corrosion-fatigue tests were carried out using an applied stress ratio (R) of 0.1, 15 Hz frequency (air at RT and-54 C) and 1 Hz frequency (seawater fog) using a sinusoidal wave form. In the near-threshold region, in air and at RT it was found a ?Kth = 2.9 MPa.m1/2 for AA2050-T84, in saline environment this value increased to ?Kth = 4.9 MPa.m1/2, due to closure effect through wedge effect by the corrosion products. At the beginning of the Paris-Erdogan region, the crack closure effect was not present for the AA7050-T7451, but persisted for the AA2050 Al-li alloy. It was observed that both alloys were equally affected by temperature reduction. When the saline environment is considered it was observed that the AA7050-T7451 presents lower m value (2.6) than the one for AA2050-T84 (3.4), meaning a lower FCG rate variation with ?K, however it presented the highest C value, as a consequence the worst FCG behavior.

Valdisser P.A.M.R.,Laboratorio Of Biotecnologia | Pappas G.J.,University of Brasilia | de Menezes I.P.P.,Instituto Federal Goiano IF Goiano | Muller B.S.F.,University of Brasilia | And 6 more authors.
Molecular Genetics and Genomics | Year: 2016

Researchers have made great advances into the development and application of genomic approaches for common beans, creating opportunities to driving more real and applicable strategies for sustainable management of the genetic resource towards plant breeding. This work provides useful polymorphic single-nucleotide polymorphisms (SNPs) for high-throughput common bean genotyping developed by RAD (restriction site-associated DNA) sequencing. The RAD tags were generated from DNA pooled from 12 common bean genotypes, including breeding lines of different gene pools and market classes. The aligned sequences identified 23,748 putative RAD-SNPs, of which 3357 were adequate for genotyping; 1032 RAD-SNPs with the highest ADT (assay design tool) score are presented in this article. The RAD-SNPs were structurally annotated in different coding (47.00 %) and non-coding (53.00 %) sequence components of genes. A subset of 384 RAD-SNPs with broad genome distribution was used to genotype a diverse panel of 95 common bean germplasms and revealed a successful amplification rate of 96.6 %, showing 73 % of polymorphic SNPs within the Andean group and 83 % in the Mesoamerican group. A slightly increased He (0.161, n = 21) value was estimated for the Andean gene pool, compared to the Mesoamerican group (0.156, n = 74). For the linkage disequilibrium (LD) analysis, from a group of 580 SNPs (289 RAD-SNPs and 291 BARC-SNPs) genotyped for the same set of genotypes, 70.2 % were in LD, decreasing to 0.10 %in the Andean group and 0.77 % in the Mesoamerican group. Haplotype patterns spanning 310 Mb of the genome (60 %) were characterized in samples from different origins. However, the haplotype frameworks were under-represented for the Andean (7.85 %) and Mesoamerican (5.55 %) gene pools separately. In conclusion, RAD sequencing allowed the discovery of hundreds of useful SNPs for broad genetic analysis of common bean germplasm. From now, this approach provides an excellent panel of molecular tools for whole genome analysis, allowing integrating and better exploring the common bean breeding practices. © 2016 Springer-Verlag Berlin Heidelberg

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