J. H. M. Viana

Duplicate and Conquer: Multiple Homologs of PHOSPHORUS-STARVATION TOLERANCE1 Enhance Phosphorus Acquisition and Sorghum Performance on Low-Phosphorus Soils

Sorghum homologs of a rice gene contributing to P-starvation tolerance enhance P uptake and crop performance in low-P soils via modulation of root system morphology and architecture. Low soil phosphorus (P) availability is a major constraint for crop production in tropical regions. The rice (Oryza sativa) protein kinase, PHOSPHORUS-STARVATION TOLERANCE1 (OsPSTOL1), was previously shown to enhance P acquisition and grain yield in rice under P deficiency. We investigated the role of homologs of OsPSTOL1 in sorghum (Sorghum bicolor) performance under low P. Association mapping was undertaken in two sorghum association panels phenotyped for P uptake, root system morphology and architecture in hydroponics and grain yield and biomass accumulation under low-P conditions, in Brazil and/or in Mali. Root length and root surface area were positively correlated with grain yield under low P in the soil, emphasizing the importance of P acquisition efficiency in sorghum adaptation to low-P availability. SbPSTOL1 alleles reducing root diameter were associated with enhanced P uptake under low P in hydroponics, whereas Sb03g006765 and Sb03g0031680 alleles increasing root surface area also increased grain yield in a low-P soil. SbPSTOL1 genes colocalized with quantitative trait loci for traits underlying root morphology and dry weight accumulation under low P via linkage mapping. Consistent allelic effects for enhanced sorghum performance under low P between association panels, including enhanced grain yield under low P in the soil in Brazil, point toward a relatively stable role for Sb03g006765 across genetic backgrounds and environmental conditions. This study indicates that multiple SbPSTOL1 genes have a more general role in the root system, not only enhancing root morphology traits but also changing root system architecture, which leads to grain yield gain under low-P availability in the soil.

Variabilidade espacial e temporal da produtividade de culturas sob sistema plantio direto

O objetivo deste trabalho foi avaliar a variabilidade espacial e temporal da produtividade de soja, milho e trigo, em uma lavoura comercial de 57 ha, nao irrigada, manejada ha mais de dez anos sob sistema plantio direto, em um Latossolo Vermelho distrofico tipico, em Palmeira das Missoes, RS. A coleta de dados de produtividade de seis cultivos, entre 2000 e 2005, foi realizada por colhedora equipada com monitor de produtividade. Analises estatisticas e geoestatisticas foram realizadas a fim de avaliar a variabilidade espacial e a presenca de dependencia espacial ao longo dos anos. A produtividade da soja, do milho e do trigo alcancada apresenta variabilidade com continuidade espacial, correlacionando-se entre si, ao longo dos anos. Em anos de deficit hidrico, verifica-se aumento da variabilidade espacial da produtividade. A cultura do milho e mais eficiente do que a da soja em detectar a variabilidade espacial da produtividade existente na lavoura.

Effect of oxygen tension and serum during IVM on developmental competence of bovine oocytes.

With an aim to improve the in vitro production of bovine embryos, the present study investigated the effect of serum and oxygen tension during IVM on oocyte developmental competence. Four experimental groups were evaluated: G1, 10% oestrus cow serum (OCS) with 20% O(2); G2, 0.1% polyvinyl alcohol (PVA) with 20% O(2); G3, 10% OCS with 5% O(2); and G4, 0.1% PVA with 5% O(2). The proportion of MII oocytes, blastocyst rates and total cell number were not affected (P > 0.05) when the OCS was replaced with PVA under 5% O(2), whereas a higher (P < 0.05) blastocyst rate and total cell number were found with OCS compared with PVA under 20% O(2). The apoptosis index was lower in blastocysts from oocytes matured with PVA under 5% O(2) (G4) compared with other groups (G1, G2 and G3), but no differences (P > 0.05) were found in maturation and blastocyst rates. Significant differences were found in the amount of specific transcripts in oocytes matured under different conditions. In conclusion maturation with PVA and 5% O(2) provides an efficient in vitro culture condition for the maturation of bovine oocytes.

Back to Acid Soil Fields: The Citrate Transporter SbMATE Is a Major Asset for Sustainable Grain Yield for Sorghum Cultivated on Acid Soils

Aluminum (Al) toxicity damages plant roots and limits crop production on acid soils, which comprise up to 50% of the world’s arable lands. A major Al tolerance locus on chromosome 3, AltSB, controls aluminum tolerance in sorghum [Sorghum bicolor (L.) Moench] via SbMATE, an Al-activated plasma membrane transporter that mediates Al exclusion from sensitive regions in the root apex. As is the case with other known Al tolerance genes, SbMATE was cloned based on studies conducted under controlled environmental conditions, in nutrient solution. Therefore, its impact on grain yield on acid soils remains undetermined. To determine the real world impact of SbMATE, multi-trait quantitative trait loci (QTL) mapping in hydroponics, and, in the field, revealed a large-effect QTL colocalized with the Al tolerance locus AltSB, where SbMATE lies, conferring a 0.6 ton ha–1 grain yield increase on acid soils. A second QTL for Al tolerance in hydroponics, where the positive allele was also donated by the Al tolerant parent, SC283, was found on chromosome 9, indicating the presence of distinct Al tolerance genes in the sorghum genome, or genes acting in the SbMATE pathway leading to Al-activated citrate release. There was no yield penalty for AltSB, consistent with the highly localized Al regulated SbMATE expression in the root tip, and Al-dependent transport activity. A female effect of 0.5 ton ha–1 independently demonstrated the effectiveness of AltSB in hybrids. Al tolerance conferred by AltSB is thus an indispensable asset for sorghum production and food security on acid soils, many of which are located in developing countries.

The allograft valve in heart transplantation and valve replacement: Genetic assessment of the origin of the cells by means of deoxyribonucleic acid profiles

Assessment of the cellular origin of allograft valves is essential in comprehending their biologic behavior and in improving preparation methods. In this study we retrospectively analyzed 10 allografts obtained from patients who underwent valve replacement or heart transplantation. Histologic evaluation and deoxyribonucleic acid amplification by polymerase chain reaction technology with fluorescence labeled primers was performed on different parts of the valve leaflets. Automated analyses of the obtained amplimers showed in the heart transplantation group the presence of receptor cells interspersed with native donor cells in three cases. Preliminary results for the valve replacement group are inconclusive as yet.

Use of ultrasound biomicroscopy to evaluate induced ovarian follicular growth and ovulation in mice

Recent advances in image technology, including significant gains in spatial resolution, have made realtime sequential ovarian evaluations possible in small rodents, allowing longitudinal (continued) studies of the ovarian cycle and reducing the required number of experimental animals. The aim of this study was to evaluate exogenous stimulated follicular growth in mice using high-resolution ultrasound technology. Female mice (n = 15) received a 5 IU intraperitoneal injection of equine chorionic gonadotropin (eCG) and 48 h later a 5 IU injection of human chorionic gonadotropin (hCG), and were allowed to mate thereafter. In experiment 1, animals (n = 7) were evaluated every 6 h, from 3 to 51 h after eCG injection, with an ultrasound biomicroscopy (UBM) equipped with a realtime 45 MHz microvisualization probe (RMV 707b). The ovaries were identified and follicular population quantified, and follicles were classified according to the diameter as small (≤449 μm) or large (≥450 μm). A significant change in the distribution of follicle population according to category was observed only 45 h after eCG injection (P < 0.05). In experiment 2, animals (n = 8) were evaluated every 2 h, from 2 h to 10 h after hCG treatment. The largest follicles reached a maximum size (596.7 ± 106.0 μxm) 5.8 ± 2.3 h after hCG injection. As expected, the population of large follicles decreased thereafter, indicating the progress of ovulations, but large follicles were still detected late after treatment (10.1 ± 1.1 h). In conclusion, UBM can be used to evaluate follicle dynamics in superstimulated mice (C57BL/6 and BALB/c); significant changes in follicle distribution only occur at later stages after eCG stimulation; and hCG-induced ovulations may not occur synchronously in mice.

Estimation of biometric parameters from cattle rump using free-hand scanning and a 3D data processing algorithm

ABSTRACT The quantity and quality of phenotypic data recovered from farm animals became a bottleneck for breeding programmes, and new tools are required to overcome this problem. This study evaluated the use of a portable structured light scanner and a 3D modelling to recover biometric information of the rump region in cattle. Virtual 3D models were created based on coordinates extracted from the points-cloud obtained through reverse engineering. A MATLAB algorithm was implemented to identify reference points, which were used to automatically calculate rump width, length, and angle. Results were compared to measurements performed directly in vivo and in the 3D models. There was no difference among rump parameter values obtained among biometry methods, though an interaction with body condition score was observed for rump width. The algorithm allowed evaluating correlations within biometric parameters, as well as extracting silhouettes of selected areas to evaluate differences caused by the mobilisation of subcutaneous fat.

Caracterização, potencial agrícola e perspectivas de manejo de solos leves no Brasil

Light soils occupy 8% of the Brazilian territory and are especially expressive in the new and last agricultural frontier in Brazil: the Matopiba region – in the states of Maranhão, Tocantins, Piauí, and Bahia –, where they represent 20% of the area. These soils fit into the textural classes of sand and loamy sand or sandy loam, down to 0.75-m soil depth or deeper, and they are mainly represented by Neossolos Quartzarênicos (Quartzipsamments) and, partly, by Latossolos (Oxisols) and Argissolos (Ultisols). The understanding of soil functioning depends on the establishment of distinguishing criteria for: organic matter dynamics; content and mineralogy of the clay fraction; coarse sand and total sand contents, in relation to those of fine sand; mean diameter of the sand fraction; and water retention capacity. These criteria can contribute for the zoning and for the conservation and fertility management of light soils, as well as for the estimation of their agricultural potential. Integrated production systems, such as crop-livestock and crop-livestock-forestry integration, besides no-tillage with crop rotation, mixed forestry planting with legumes, and the use of green manure and cover crops are relevant for the proper management of these soils. The objective of this review was to characterize light soils and to highlight the main challenges regarding their agricultural potential and their conservation and fertility managements, in face of the expansion and consolidation of the new Brazilian agricultural frontier.

Decomposição e liberação de macronutrientes da palhada de milho e braquiária, sob integração lavoura-pecuária no cerrado baiano.

Knowledge of the dynamics of decomposition and nutrient release in production systems is of great importance for management of soil fertility and reducing waste of resources. In this regard, an experiment was conducted in Cerrado (Brazilian tropical savanna) soil from the western region of Bahia, Brazil, for the purpose of studying the decomposition and nutrient release from corn stover plus Brachiaria ruziziensis straw under an integrated crop-livestock system. The evaluations were performed using litterbags collected at 0, 15, 40, 110, 170, and 220 days after desiccation of the stover/straw, which occurred in October 2008. Initial total dry matter was around 6.6 Mg ha-1, with a half-life of 115 days. Nutrient release from this volume of straw (with the percentage in relation to the total amount of nutrients accumulated in the plant) up to the end of evaluations was 29.3 (62 %), 7.8 (80 %), 42.2 (94 %), 48.6 (74 %), 17.0 (81 %), and 7.7 (79 %) kg ha-1 of N, P, K, Ca, Mg, and S, respectively. These results assist management of crop fertilization and result in less waste of natural resources. As an example, transforming the amounts of the three main macronutrients (N, P, and K) released up to 110 days (a period of a certain coincidence with the flowering of the main successor crop) into amounts of fertilizer, there would be savings of R

Chemical, physical and micromorphological properties of termite mounds and adjacent soils along a toposequence in Zona da Mata, Minas Gerais State, Brazil

243.00 per hectare.