Alexandre Rossetto Garcia

Molecular mapping of soybean rust ( Phakopsora pachyrhizi ) resistance genes: discovery of a novel locus and alleles

Soybean production in South and North America has recently been threatened by the widespread dissemination of soybean rust (SBR) caused by the fungus Phakopsora pachyrhizi. Currently, chemical spray containing fungicides is the only effective method to control the disease. This strategy increases production costs and exposes the environment to higher levels of fungicides. As a first step towards the development of SBR resistant cultivars, we studied the genetic basis of SBR resistance in five F2 populations derived from crossing the Brazilian-adapted susceptible cultivar CD 208 to each of five different plant introductions (PI 200487, PI 200526, PI 230970, PI 459025, PI 471904) carrying SBR-resistant genes (Rpp). Molecular mapping of SBR-resistance genes was performed in three of these PIs (PI 459025, PI 200526, PI 471904), and also in two other PIs (PI 200456 and 224270). The strategy mapped two genes present in PI 230970 and PI 459025, the original sources of Rpp2 and Rpp4, to linkage groups (LG) J and G, respectively. A new SBR resistance locus, rpp5 was mapped in the LG-N. Together, the genetic and molecular analysis suggested multiple alleles or closely linked genes that govern SBR resistance in soybean.

Sistema silvipastoril na Amazônia: ferramenta para elevar o desempenho produtivo de búfalos

Agroforestry systems are alternative techniques for the soil used, involving forest species, agricultural crops and livestock. Silvopastoral Systems are a less aggressive alternative, contributing to the reversion of altered areas and to raise biodiversity. These systems explore natural resources, controlled erosive process, improve the soil structure and balance the microorganisms activity, promote better quality of the pastures, providing animal ambience, due to the efficient shade of pastures. Thus, provide barrier against the winds, decreasing thermal stress and improving animal performance. This review describes the silvopastoral system as a strategy for management of buffaloes, aiming to raise productive performance.

Variáveis fisiológicas de búfalas leiteiras criadas sob sombreamento em sistemas silvipastoris

The objective of this work was to evaluate the use of silvipastural systems as a management option to maintain physiological features of dairy buffaloes and to provide higher levels of thermal comfort. Fifty-six adult females (79±44.12 months; 575±92.90 kg) were evaluated: 30 in an unshaded silvipastural system and 26 in a silvipastural system with 19.9% of shaded area. Heart and respiratory rates, rectal temperature and animal comfort index were evaluated weekly. Means were submitted to analysis of variance, and meteorological and physiological data were correlated by Pearsons method. Shading significantly reduced heart rate and rectal temperature. In 71.4% of the observations, the animals kept in the silvipastural system with shaded area showed thermal comfort index closer to the ideal level. Shading maintains the physiological parameters of dairy buffaloes closer to normal, and improves the animal comfort index. The adoption of silvipastural systems for buffalo production in tropical areas can avoid energy loss due to thermolysis.

Assessment of surface temperatures of buffalo bulls (Bubalus bubalis) raised under tropical conditions using infrared thermography

This paper aimed to evaluate the surface temperatures of buffalo bulls using infrared thermography, considering four distinct anatomical parts over time, and to correlate surface temperatures and thermal comfort indexes. The humid tropical climate (Koppens Afi) was predominant in the research station where the experiment was performed and the trial lasted from April to August. Ten bulls (n=10) were evaluated every 25 days (morning: 6:00-9:00; afternoon: 12:00-15:00) and the parameters assessed were respiratory rate (RR), rectal temperature (RT), and the thermograms of surface temperature for orbital area (ORB), right flank (RF), left flank (LF) and scrotum (SCR). Climatological data was continuously monitored and the Temperature and Humidity Index (THI) and the Index of Comfort of Benezra (ICB) were calculated. The average values of THI were ≥78, and significant differences between shifts were observed (P<0.05). The ICB ranged from 1.96 to 2.25 and significant differences were observed for shifts and throughout the months (P<0.05). The averages of surface temperatures were RT=38.2±0.5°C, ORB=36.1±0.8°C, LF=33.5±2.5°C, RF=35.4±1.7oC and SCR=33.3±1.1°C, which exhibited significant differences for shifts and throughout the months (P<0.05). Positive correlations were obtained between THI and ORB (0.72), RF (0.77), LF (0.75) and SCR (0.41) (P<0.0001). The maximum temperature of ORB showed the highest correlation with RT (0.58, P<0.0001). Therefore, the surface temperatures are subject to climatic variations and increase throughout the day, due to the variation in thermal comfort indexes, and the maximum ORB temperature was the parameter most related to rectal temperature. Lastly, the results indicate that IRT may be a useful non-invasive and accurate tool to detect the variations in ORB, LF, RF and SCR temperature in buffalo bulls.

Conforto ambiental de bezerros bubalinos (Bubalus bubalis Linnaeus, 1758) em sistemas silvipastoris na Amazônia Oriental

Foi analisado o efeito de dois sistemas silvipastoris nos indices de conforto ambiental e alteracoes nos parâmetros fisiologicos de bezerros bubalinos criados na Embrapa Amazonia Oriental, Belem-PA (clima Afi), no Periodo 1 (abril a setembro/2007) e Periodo 2 (outubro/2007 a marco/2008). Foram inseridos onze bezerros no Sistema Silvipastoril 1 (SSP1), que apresentava sombreamento util nas pastagens de 18 a 21%, e oito no Sistema Silvipastoril 2 (SSP2), sem sombreamento, com lago para banho. Foram mensuradas as variaveis fisiologicas: temperatura retal (TR), frequencia respiratoria (FR), temperatura da pele (TP), e calculados o Indice de Temperatura e Umidade (ITU) e Indice de Conforto de Benezra (ICB), nos dois periodos experimentais, comparados pelo Teste Tukey (P < 0,05). O ITU apresentou diferenca estatistica entre horarios (P < 0,05) e periodo do ano (P < 0,05), e oscilou de 73,5 ± 1,3 ate 82,2 ± 0,8. A TR apresentou diferenca estatistica entre horarios e periodos do ano (P < 0,05), com amplitude de 38,3 ± 0,26 a 39,3 ± 0,38 °C. A FR apresentou diferenca significativa entre horarios (P < 0,05), com amplitude de 32,2 ± 9,2 a 56,5 ± 19,0 mov min-1, consideradas acima dos niveis normais, enquanto a TP foi diferente estatisticamente entre periodos e horarios (P < 0,05) e variou de 23,6 ± 8,3 a 31,7 ± 5,4 °C. Nos Periodos 1 e 2 e nos dois SSPs, os ICBs estiveram acima do valor ideal, variando de 2,46 ± 0,33 a 3,31 ± 0,62 (SSP1) e 2,42 ± 0,30 a 3,45 ± 0,66 (SSP2).

Análise multivariada dos componentes da resistência à ferrugem-asiática em genótipos de soja

The objective of this study was to detail the infection cycles of Phakopsora pachyrhizi Syd. & P. Syd. in soybean genotypes, in order to establish a group of the most promising genotypes for use as sources of resistance to Asian soybean rust. The infection cycle components were quantifi ed in 48 genotypes. The assessments consisted of: type of lesion, intensity of sporulation, severity, number of lesions and uredinias, and productivity of urediniospores. The cluster analysis formed four groups: A - developed the highest amount of disease; B - developed the lowest amount of disease; C - low initial resistance; and D - high initial resistance. All the genotypes of groups B, C and D had RB (redish-brown) lesions and varied for initial resistance, delayed resistance, intensity of sporulation, stability of the qualitative response, productivity of urediniospores, and number of days to reach 50% of the maximum severity. Qualitative responses and disease severity evaluations refl ect the combined effects of resistance on all the infection components and show practical importance in genotypes differentiation, regarding disease resistance. The genotypes of groups B, C and D presented qualitative and quantitative resistance, in different degrees, and they are promising genotypes as sources of resistance to Asian soybean rust.

Conforto térmico de búfalas em sistema silvipastoril na Amazônia Oriental

The objective of this work was to evaluate the effects of a silvipasture system on the thermal comfort of 20 female buffaloes, from which 10 raised in under nonshaded paddocks (SS) and 10 in paddocks shaded by Racosperma mangium (CS), in Belem county, PA, Brazil. All animals were fed in pastures with Urochloa humidicola, and had free access to drinking water and mineral salt. Every three days, measurements were made for air temperature (TA), relative humidity ( UR ), black globe temperature (TGN), rectal temperature (TR), respiratory rate (FR), heart rate (FC), and body surface temperature (TSC), in the morning (7 AM) and in the afternoon (1 PM). The values of TR, TSC, RR and FR, mainly for the SS group, were higher in the afternoon. The TR, TSC and FR showed a significant and positive correlation with TA and the temperature and humidity index (ITGU), and a negative correlation with UR . These correlations were higher for the less rainy period. The FR showed significant and positive correlations with TA and ITGU, during both the most and the less rainy seasons, and negative correlations with UR only in the rainy season. The forestation of pasture areas is efficient to increase the thermal comfort for Murrah females, especially in the afternoon.

Biometria testicular, eletroejaculação e características seminais de caititus, Tayassu tajacu Linnaeus, 1758 (Mammalia, Artiodactyla, Tayassuidae) mantidos em cativeiro na Amazônia Oriental

Estudos relacionados a obtencao e avaliacao de semen de Tayassu tajacu sao escassos, sendo necessarias pesquisas a respeito. Os objetivos do estudo foram avaliar a biometria testicular de caititus adultos cativos, testar a eficiencia da eletroejaculacao para obtencao de semen e avaliar suas caracteristicas seminais ao longo do ano. Procedeu-se a eletroejaculacao em oito animais adultos e as amostras de semen colhidas foram avaliadas quanto as caracteristicas fisicas e morfologicas. Os animais tinham testiculo esquerdo com 3,8 ± 0,4 cm X 2,6 ± 0,3 cm e 2,3 ± 0,2 de consistencia, e testiculo direito com 3,8 ± 0,5 cm X 2,7 ± 0,3 cm e 2,3 ± 0,2 de consistencia. A taxa de sucesso nas colheitas foi de 75,21%. O semen possuiu: volume 0,81 ± 0,86 mL, concentracao 137,44 ± 153 x 106 sptz mL-1, pH 7,92 ± 0,73, motilidade 52,66 ± 28,79%, vigor 2,2 ± 0,8, integridade de membrana plasmatica 55,84 ± 28,55%, defeitos maiores 22,87 ± 12,93%, defeitos menores 9,11 ± 5,88% e defeitos totais 31,52 ± 13,81%. Os animais apresentaram simetria testicular, a eletroejaculacao se mostrou eficiente para a obtencao de ejaculados em caititus e as flutuacoes observadas na producao seminal nao foram suficientes para caracteriza-los como animais de reproducao sazonal.

Perfil hematológico de búfalas da raça Murrah, criadas ao sol e à sombra, em clima tropical da Amazônia Oriental

Foram avaliadas as respostas hematologicas de 20 bufalas, criadas ao sol (grupo - SS) e a sombra (grupo - CS), em Belem, Para. Os animais do grupo CS (n = 10) estavam em sistema silvipastoril, com Racosperma mangium e os do SS (n = 10), em piquetes sem sombra, em pastagem de Brachiaria humidicola, agua para beber e sal mineral. Foram mensuradas temperatura do ar (TA), umidade relativa do ar (UR) e temperatura de globo negro, em cada tratamento. A coleta de sangue para eritrograma e numero total de leucocitos foi realizada a cada 14 dias, as 13 h, durante o ano de 2009. Atraves da analise de variância constatou-se que em todos os periodos do ano, a TA e indice de temperatura de globo e umidade (ITGU) foram diferentes (P < 0,05), com niveis mais elevados no grupo SS. No periodo mais chuvoso, o grupo CS apresentou valores elevados de leucocitos, enquanto nos periodos de transicao e menos chuvoso, foram maiores no grupo SS. No periodo menos chuvoso do ano, o grupo SS apresentou maiores valores de hemacias. O teor de hemoglobina teve maiores niveis (P < 0,05) nos periodos de transicao e menos chuvoso. Somente a hemoglobina teve correlacao significativa e negativa (P < 0,05) com a UR. Conclui-se que as novilhas bufalas Murrah estao sujeitas a um ambiente hostil e o periodo menos chuvoso e o mais propicio a causar estresse termico.

Hormonal changes in female buffaloes under shading in tropical climate of Eastern Amazon, Brazil

The hormonal responses of 20 female buffaloes raised under the sun (SS group) or in the shade (CS group) in Belem, Para, Brazil, were assessed. The CS group (n = 10) was kept in a silvopasture system featuring Racosperma mangium, whereas the SS group (n = 10) was kept in paddocks without shade featuring Brachiaria humidicola, drinking water, and mineral salt. The following parameters were measured for each treatment: dry-bulb temperature (AT), relative humidity (RH), and black-globe temperature in order to calculate the globe temperature and humidity index (GTHI). Blood sample collections to quantitatively determine levels of cortisol, triiodothyronine (T3), and thyroxine (T4) were performed every 14 days, at 13.00 h. Different seasons of the year were also assessed: rainy (January-April), transition (May-July), and less rainy (August-December). Analysis of variance revealed that AT and the index of global temperature and humidity (GTHI) differed between groups; specifically, higher values were found in the SS group, which shows how important silvopastoral systems are in buffalo farming in tropical climates. Relative humidity was significantly different across seasons and particularly high in the rainy season. The treatments influenced cortisol such that higher values were observed in the SS group. The highest mean cortisol levels were recorded during the rainy and less rainy seasons, whereas the highest T3 and T4 levels were recorded only during the rainy season. Triiodothyronine and thyroxine were negatively correlated with AT and GTHI and positively correlated with RH. Silvopastoral systems provide thermal comfort to buffaloes, and the less rainy season is more likely to cause heat stress.