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Several equipments and methodologies have been developed to make available precision agriculture, especially considering the high cost of its implantation and sampling. An interesting possibility is to define management zones aim at dividing producing areas in smaller management zones that could be treated differently, serving as a source of recommendation and analysis. Thus, this trial used physical and chemical properties of soil and yield aiming at the generation of management zones in order to identify whether they can be used as recommendation and analysis. Management zones were generated by the Fuzzy C-Means algorithm and their evaluation was performed by calculating the reduction of variance and performing means tests. The division of the area into two management zones was considered appropriate for the present distinct averages of most soil properties and yield. The used methodology allowed the generation of management zones that can serve as source of recommendation and soil analysis; despite the relative efficiency has shown a reduced variance for all attributes in divisions in the three subregions, the ANOVA did not show significative differences among the management zones. KEYWORDS:Precision agriculture, spatial variability, fuzzy clustering, management zones, autocorrelation, cross-correlation. DEFINIÇÃO DE UNIDADES DE MANEJO USANDO ATRIBUTOS QUÍMICOS E FÍSICOS DO SOLO EM UMA ÁREA DE SOJA RESUMO:Diversos equipamentos e metodologias vêm sendo desenvolvidos para tornar a agricultura de precisão disponível, especialmente considerando o alto custo de sua implantação e de amostragem. Uma possibilidade interessante é definir a área em unidades menores de produção que podem ser tratadas de maneira diferente, servindo como fonte de recomendação e análise. Assim, o presente estudo utilizou propriedades físicas e químicas do solo e de produtividade visando à geração de unidades de manejo, a fim de identificar se estas podem ser usadas como recomendação e análise. Unidades de manejo foram geradas pelo algoritmo Fuzzy C-Means, e sua avaliação foi realizada por meio da redução da variância e realização de testes de comparação de médias. A divisão da área em duas unidades de manejo foi considerada adequada, e as médias apresentaram-se distintas da maioria das propriedades do solo e produtividade; a metodologia utilizada permitiu a geração de unidades de manejo que podem servir como fonte de recomendação e análise do solo. Apesar de a eficiência relativa demonstrar que houve redução da variância para todos os atributos na divisão em três sub-regiões, a ANOVA não apresentou diferenças significativas entre as unidades de manejo. PALAVRAS-CHAVE:

This report provides the first estimates of the genetic basis of all key breast muscle myopathies (BMM) in broiler chickens [Deep pectoral myopathy, wooden breast, white striping and spaghetti breast] and their relationship with body weight and breast yield. Data from a pure bred high yielding commercial broiler line were analysed to estimate the genetic parameters using a multivariate animal model with the appropriate fixed effects and permanent environmental effect of the dam. Heritabilities of the BMM ranged from 0.04 to 0.25 and the genetic correlation of the BMM with body weight and breast yield ranged from-0.06 to 0.41. Here we highlight that the genetic variance of BMM accounts for a low proportion of the phenotypic variance and the BMM have a low genetic relationship with performance traits. The large contribution of residual variance to the phenotypic variance for the BBM was >71.5% which indicates the importance of the non-genetic effects on BMM. The data presented also show that the moderate to low genetic influence for the development of BMM can be used, through balanced selection, to reduce the myopathy incidence in the long term. The impact of genetic selection against BMM was tested empirically by comparing the incidence of WB and % breast yield of a commercial broiler with a high generation (HG) broiler. The HG broiler used represents 2 years of genetic improvement compared to the commercial broiler; the HG broiler had an 18.4% relative decrease in WB and a 1.02% relative increase in breast yield compared to the commercial broiler. This paper describes the relationship between the genetic and non-genetic factors influencing BMM highlighting the importance of understanding the non-genetic effects on myopathy incidence. It also shows that the genetic component of BMM can be reduced whilst at the same time improving breast yield as part of balanced breeding goals.

ABSTRACT. The objective of this study was to compare tests used to identify vigor in soybean seeds and to establish a model that relates the seeds' vigor, as determined in the laboratory, with field emergence. Five soybean cultivars were evaluated based on their germination, sand emergence, immersion in sodium hypochlorite, accelerated aging, controlled deterioration, cold test, seedling growth, electrical conductivity, tetrazolium, emergence percentage, seedling length in the field and seedling dry weight. The experimental design was completely randomized and means were compared by the Tukey test at 5% probability. Assays for accelerated aging, controlled deterioration and tetrazolium showed the closest correlation to field emergence. The regression model included the sand emergence speed, germination speed index and index of sand emergence speed as the variables that best correlated with field emergence.Keywords: germination, seeds quality, regression model.Comparação de testes para análise de vigor em sementes de soja e sua relação com a emergência em campo RESUMO. O objetivo deste trabalho foi comparar testes utilizados para indicar o vigor de sementes de soja, e estabelecer um modelo que relacione os testes de vigor propostos até o momento com a emergência das plântulas em campo. Foram utilizadas cinco cultivares de soja as quais foram submetidas aos seguintes testes de vigor: germinação, emergência em areia, hipoclorito de sódio, envelhecimento acelerado, deterioração controlada, teste de frio, crescimento de plântulas (comprimento da plântula e peso de matéria seca da plântula), condutividade elétrica, tetrazólio, porcentagem de emergência e comprimento das plântulas no campo e massa seca de plântula. O delineamento experimental utilizado foi o inteiramente casualizado com quatro repetições e as médias foram comparadas pelo teste de Tukey a 5% de probabilidade. Concluiu-se que os testes de envelhecimento acelerado, deterioração controlada e tetrazólio demonstraram mais eficiência quanto a distinguir a diferença de vigor entre as cultivares. O modelo de regressão contemplou a velocidade de emergência em areia, o índice de velocidade de germinação (IVG) e o índice de velocidade de emergência em areia, como as variáveis que melhor se relacionam com a emergência em campo.Palavras-chave: germinação, qualidade de sementes, modelo de regressão.

Th e refl ectance characteristics of plants and plant canopies far from solar noon (i.e., at large solar zenith angles) or with cloudy skies are not well known. Th is is an obstacle to making real-time, variable-rate N fertilizer applications based on canopy refl ectance because such a system must work under cloudy skies and at all times of day. Our objective was to develop spectral radiometer refl ectance corrections for variations in incoming sunlight so that the same refl ectance reading would be obtained (and the same N recommendation made) for the same plants regardless of time of day or cloud conditions. Passive spectral radiometers were mounted in a stationary position about 25 cm above the corn (Zea mays L.) canopy. Readings were taken from morning until night over several days with a range of sky conditions (sunny, overcast, and partly cloudy). Experiments were done in the fi eld in April and May on greenhouse-grown corn ranging from V10 to R2 growth stages. Sun angle, time of day, and cloud cover all infl uenced refl ectance measured from the corn canopy. When regression models were applied to correct refl ectance values to reference conditions for these variables, coeffi cients of variation were reduced by 29 to 56% for vegetation indexes and by 43 to 56% for refl ectance values. Th e near-infrared/green ratio and the green normalized diff erence vegetation index were the indices most sensitive to N defi ciency among six analyzed indices.

R ESU M OOs atributos químicos e físicos do solo apresentam, frequentemente, dependência espacial. Portanto, é imprescindível estudar sua variabilidade espacial visando ao manejo mais preciso da lavoura, a redução do impacto ambiental, a otimização do uso de máquinas e o aumento da eficiência das equipes de trabalho. Assim, o objetivo deste trabalho foi avaliar a variabilidade espacial de atributos físicos de um Latossolo Vermelho distroférrico típico após o cultivo de soja. Os dados foram coletados em uma área de 2 ha cultivada sob sistema de plantio direto utilizando-se uma grade amostral de 30 x 33 m, em que foram avaliados os parâmetros: macroporosidade, microporosidade, porosidade total, densidade e umidade do solo, na camada de 0 -0,1 m; após as análises exploratória e geoestatística, os modelos teóricos foram ajustados aos semivariogramas para cada atributo; já a interpolação dos dados foi realizada utilizando-se a krigagem ordinária, verificando-se que todas as variáveis estudadas apresentaram dependência espacial, que variou entre moderada (macroporosidade, porosidade total e umidade do solo) e forte (microporosidade e densidade do solo), em função do coeficiente de efeito pepita. Palavras-chave: geoestatística, porosidade do solo, umidade do solo, densidade do solo Spatial variability of physical attributes of a distroferric Red Latosol after soybean crop A B ST R A C TThe chemical and physical properties of a soil often show a spatial dependence. Thus, it is important to study their spatial variability, aiming to improve the crop management, to reduce the environmental impact, to optimize the machinery use, and to increase the efficiency of staff. So, this study aimed to evaluate the spatial variability of the physical properties of a distroferric Red Latosol (Typic Haplorthox) after soybean crop. The data were collected in an area of 2 ha managed under no tillage system, using a sampling grid of 30 x 33 m, where it was evaluated the macro, micro and the total porosity, the bulk density and the soil water content in 0 -0.1 m layer. After the exploratory and geostatistical analyses, the theoretical models were set to the semivariograms for each attribute. The data interpolation was performed using the ordinary kriging. All the variables showed spatial dependence, which ranged from moderate (macroporosity, total porosity and soil water content) to strong (microporosity and bulk density), according to the nugget effect coefficient.