Determination of optimal number of independent components in yield traits in rice

The principal component regression (PCR) and the independent component regression (ICR) are dimensionality reduction methods and extremely important in genomic prediction. These methods require the choice of the number of components to be inserted into the model. For PCR, there are formal criteria; however, for ICR, the adopted criterion chooses the number of independent components (ICs) associated to greater accuracy and requires high computational time. In this study, seven criteria based on the number of principal components (PCs) and methods of variable selection to guide this choice in ICR are proposed and evaluated in simulated and real data. For both datasets, the most efficient criterion and that drastically reduced computational time determined that the number of ICs should be equal to the number of PCs to reach a higher accuracy value. In addition, the criteria did not recover the simulated heritability and generated biased genomic values.

Estruturas fetais e suas correlações com a predição do dia antes do parto em raças de cães miniaturas / Fetal structures and their correlations with a prediction of the parturition date in the miniature canine breeds

Avaliou-se a correlação entre estruturas fetais e extrafetais com a predição do dia antes do parto (DAP) em raças de cães miniaturas. Para isso, realizou-se um experimento, utilizando-se 12 cadelas, com peso corporal entre 3,0kg e 5,0kg, sendo seis da raça Chihuahua, duas da raça Shih-Tzu, duas da raça Spitz Alemão e duas da raça Yorkshire. Foram mensurados, por meio da ultrassonografia, diâmetro biparietal (DBP), diâmetro torácico (DTX), diâmetro abdominal (DAB), comprimento craniocaudal (CCC), diâmetro da cavidade coriônica interna (DCI) e espessura da placenta (EP), a partir do 15º dia após a última monta. Foram estudadas as correlações simples e a significância dos coeficientes de regressão linear simples e o coeficiente de determinação (R), com nível de significância estabelecido em P<0,05. Entre os parâmetros avaliados, DBP, DTX, DAB e CCC foram os mais correlacionados com tempo gestacional, podendo ser utilizados para prever dia antes do parto em cadelas de raças miniaturas.(AU)

The correlation between fetal and extra-fetal structures with the pre-delivery prediction (DAP) in miniature dog breeds was evaluated. For this, an experiment was carried out using 12 bitches, with body weight between 3.0kg and 5.0kg, being 6 Chihuahua, 2 Shih-Tzu, 2 German Spitz and 2 Yorkshire breed. The Biparietal Diameter (BD), Thoracic Diameter (TD), Abdominal Diameter (AD), Crown-rump length (CRL), Internal Chorionic Cavity Diameter (ICD) and Placenta Thickness (PT) were measured by ultrasonography from the 15th day after the last mating. The simple correlations and significance of simple linear regression coefficients and the coefficient of determination (R) were studied, with a significance level of P<0.05. BD, T, AD and CRL were the most correlated with gestational time, and can be used to predict day before delivery in miniature breed bitches.(AU)

Estruturas fetais e suas correlações com a predição do dia antes do parto em raças de cães miniaturas / Fetal structures and their correlations with a prediction of the parturition date in the miniature canine breeds

Avaliou-se a correlação entre estruturas fetais e extrafetais com a predição do dia antes do parto (DAP) em raças de cães miniaturas. Para isso, realizou-se um experimento, utilizando-se 12 cadelas, com peso corporal entre 3,0kg e 5,0kg, sendo seis da raça Chihuahua, duas da raça Shih-Tzu, duas da raça Spitz Alemão e duas da raça Yorkshire. Foram mensurados, por meio da ultrassonografia, diâmetro biparietal (DBP), diâmetro torácico (DTX), diâmetro abdominal (DAB), comprimento craniocaudal (CCC), diâmetro da cavidade coriônica interna (DCI) e espessura da placenta (EP), a partir do 15º dia após a última monta. Foram estudadas as correlações simples e a significância dos coeficientes de regressão linear simples e o coeficiente de determinação (R), com nível de significância estabelecido em P<0,05. Entre os parâmetros avaliados, DBP, DTX, DAB e CCC foram os mais correlacionados com tempo gestacional, podendo ser utilizados para prever dia antes do parto em cadelas de raças miniaturas.(AU)

The correlation between fetal and extra-fetal structures with the pre-delivery prediction (DAP) in miniature dog breeds was evaluated. For this, an experiment was carried out using 12 bitches, with body weight between 3.0kg and 5.0kg, being 6 Chihuahua, 2 Shih-Tzu, 2 German Spitz and 2 Yorkshire breed. The Biparietal Diameter (BD), Thoracic Diameter (TD), Abdominal Diameter (AD), Crown-rump length (CRL), Internal Chorionic Cavity Diameter (ICD) and Placenta Thickness (PT) were measured by ultrasonography from the 15th day after the last mating. The simple correlations and significance of simple linear regression coefficients and the coefficient of determination (R) were studied, with a significance level of P<0.05. BD, T, AD and CRL were the most correlated with gestational time, and can be used to predict day before delivery in miniature breed bitches.(AU)

Avaliação do modelo NRC para predição do consumo de matéria seca por vacas leiteiras manejadas em pastos tropicais / NCR Model Evaluation for prediction of dry matter intake by dairy cows managed in tropical pastures

Objetivou-se avaliar o poder preditivo do modelo do National Research Council (NRC) para gado leiteiro em estimar o consumo de matéria seca (CMS) por vacas mestiças, em pastagens tropicais. Foi efetuada uma análise conjunta de cinco estudos, contemplando três forrageiras. Foram avaliadas 132 estimativas individuais do CMS observado (CMSObs), obtidas por meio do indicador externo Cr2O3. O CMS também foi predito por meio do software do NRC (CMSPred), que, por sua vez, foi abastecido com inputs referentes aos animais e ao ambiente de criação. Os valores de CMSPred (12,7±1,6kg/d) foram semelhantes aos de CMSObs (12,3±3,3kg/d). Foram obtidas as seguintes estimativas da avaliação do poder preditivo do modelo: viés médio (-0,419kg/d), coeficiente de determinação (0,029), coeficiente de correlação (0,17; P=,051), quadrado médio do erro de predição (11,844±20,034), fator de eficiência do modelo (-0,081), coeficiente de determinação do modelo (4,1032) e fator de correção do viés (0,767). A comparação entre CMSObs e CMSPred permitiu identificar a tendência de superestimação das predições se considerado o ajuste por meio de regressão robusta para o modelo linear simples sem intercepto. Nas condições avaliadas, o modelo produz predições de CMS com satisfatória exatidão, porém com baixa precisão.(AU)

The aim of the present study was to evaluate the predictive power of estimating the dry matter intake (DMI) of crossbred cows on tropical pastures by the National Research Council (NRC) equation for dairy cattle. A joint analysis of five studies covering three forages was performed in which 132 individual estimates of observed DMI obtained through Cr2O3 as a marker. DMI was also predicted from the NRC (DMIPred) software with inputs concerning animals and breeding environment of the studies used. Predicted DMIPred average values (12.7±1.6kg/d) were similar to the observed DMIObs ones (12.3±3.3kg/d). We obtained the following estimates of the evaluation of the predictive power of the model: average bias (- 0.419kg/d), coefficient of determination (0.029), Person's correlation coefficient (0.17, P= 0.051), mean square error of prediction (11,844±20,034), model efficiency factor (- 0.081), coefficient of determination (4.1032), and bias correction factor (0.767). The comparison between DMIObs and DMIPred values allowed the identification of the overestimating tendency of the predictions demonstrated by the robust regression fit of the simple linear no intercept model. Nevertheless, the model yields predictions with satisfactory accuracy, but with low precision.(AU)

Avaliação do modelo NRC para predição do consumo de matéria seca por vacas leiteiras manejadas em pastos tropicais / NCR Model Evaluation for prediction of dry matter intake by dairy cows managed in tropical pastures

Objetivou-se avaliar o poder preditivo do modelo do National Research Council (NRC) para gado leiteiro em estimar o consumo de matéria seca (CMS) por vacas mestiças, em pastagens tropicais. Foi efetuada uma análise conjunta de cinco estudos, contemplando três forrageiras. Foram avaliadas 132 estimativas individuais do CMS observado (CMSObs), obtidas por meio do indicador externo Cr2O3. O CMS também foi predito por meio do software do NRC (CMSPred), que, por sua vez, foi abastecido com inputs referentes aos animais e ao ambiente de criação. Os valores de CMSPred (12,7±1,6kg/d) foram semelhantes aos de CMSObs (12,3±3,3kg/d). Foram obtidas as seguintes estimativas da avaliação do poder preditivo do modelo: viés médio (-0,419kg/d), coeficiente de determinação (0,029), coeficiente de correlação (0,17; P=,051), quadrado médio do erro de predição (11,844±20,034), fator de eficiência do modelo (-0,081), coeficiente de determinação do modelo (4,1032) e fator de correção do viés (0,767). A comparação entre CMSObs e CMSPred permitiu identificar a tendência de superestimação das predições se considerado o ajuste por meio de regressão robusta para o modelo linear simples sem intercepto. Nas condições avaliadas, o modelo produz predições de CMS com satisfatória exatidão, porém com baixa precisão.(AU)

The aim of the present study was to evaluate the predictive power of estimating the dry matter intake (DMI) of crossbred cows on tropical pastures by the National Research Council (NRC) equation for dairy cattle. A joint analysis of five studies covering three forages was performed in which 132 individual estimates of observed DMI obtained through Cr2O3 as a marker. DMI was also predicted from the NRC (DMIPred) software with inputs concerning animals and breeding environment of the studies used. Predicted DMIPred average values (12.7±1.6kg/d) were similar to the observed DMIObs ones (12.3±3.3kg/d). We obtained the following estimates of the evaluation of the predictive power of the model: average bias (- 0.419kg/d), coefficient of determination (0.029), Person's correlation coefficient (0.17, P= 0.051), mean square error of prediction (11,844±20,034), model efficiency factor (- 0.081), coefficient of determination (4.1032), and bias correction factor (0.767). The comparison between DMIObs and DMIPred values allowed the identification of the overestimating tendency of the predictions demonstrated by the robust regression fit of the simple linear no intercept model. Nevertheless, the model yields predictions with satisfactory accuracy, but with low precision.(AU)

Métodos de avaliação de carcaça e de carne dos animais através de predições in vivo e post mortem - revisão de literatura / Methods of evaluation of carcass and flesh of animals by predictions in vivo and post mortem - literature review

O objetivo dessa revisão é relatar os principais métodos de avaliação de carcaça e qualidade da carne através de predições in vivo e post-mortem. A avaliação de carcaça é um instrumento utilizado para caracterizar e classificar o produto final, melhorando sua qualidade, porém vários fatores influenciam na qualidade do produto final, dentre elas a raça, o sexo, a precocidade, a alimentação, o manejo pré-abate, o rigor mortis, maturação da carne, entre outros. Com isso foram desenvolvidos alguns métodos de avaliação e estes são divididos em características qualitativas da carcaça: conformação, maturidade, cor, textura, marmoreio, maciez e características quantitativas: comprimento, área de olho de lombo (AOL) e espessura de gordura subcutânea (EGS).(AU)

The objective of this review is to describe the main methods of carcass evaluation and meat quality through predictions in vivo and postmortem. The carcass evaluation is an instrument used to characterize and classify the final product, improving its quality, but several factors influence the final product quality, among them race, sex, precocity, feeding, pre-slaughter handling, the rigor mortis, the maturation of meat, among others. Therewith some methods that have been developed for assessment and these are divided into qualitative characteristics of the carcass: conformation, maturity, color, texture, marbling, meat tenderness and quantitative characteristics: length, loin eye area (REA) and fat thickness (EGS).(AU)

Métodos de avaliação de carcaça e de carne dos animais através de predições in vivo e post mortem - revisão de literatura / Methods of evaluation of carcass and flesh of animals by predictions in vivo and post mortem - literature review

O objetivo dessa revisão é relatar os principais métodos de avaliação de carcaça e qualidade da carne através de predições in vivo e post-mortem. A avaliação de carcaça é um instrumento utilizado para caracterizar e classificar o produto final, melhorando sua qualidade, porém vários fatores influenciam na qualidade do produto final, dentre elas a raça, o sexo, a precocidade, a alimentação, o manejo pré-abate, o rigor mortis, maturação da carne, entre outros. Com isso foram desenvolvidos alguns métodos de avaliação e estes são divididos em características qualitativas da carcaça: conformação, maturidade, cor, textura, marmoreio, maciez e características quantitativas: comprimento, área de olho de lombo (AOL) e espessura de gordura subcutânea (EGS).

The objective of this review is to describe the main methods of carcass evaluation and meat quality through predictions in vivo and postmortem. The carcass evaluation is an instrument used to characterize and classify the final product, improving its quality, but several factors influence the final product quality, among them race, sex, precocity, feeding, pre-slaughter handling, the rigor mortis, the maturation of meat, among others. Therewith some methods that have been developed for assessment and these are divided into qualitative characteristics of the carcass: conformation, maturity, color, texture, marbling, meat tenderness and quantitative characteristics: length, loin eye area (REA) and fat thickness (EGS).

Proposal of equations for predicting post-farrowing sow weigh

Background: Body condition score is used widely in swine production to ensure adequate nutritional levels in sows during gestation and lactation. However, body condition score is not a gold standard for the estimation of nutritional requirements in sows. Post-farrowing sow body weight assessment might serve as a useful approach for the better adjustment of the nutritional requirements during lactation; however, this approach is time-consuming, requires labor, and might result in detrimental effects on the sow behavior and welfare. The objective of the present study, therefore, was to formulate prediction equations for the estimation of post-farrowing sow weight.Materials, Methods & Results: Seven equations were formulated for predicting the post-farrowing sow body weight, by using the data from three databases, which comprised a total 522 sows (434 gilts and 88 multiparous). The sows were weighed on Day 112 of gestation and after farrowing within 12 h. The piglets birth weight was recorded within 24 h after farrowing. The equations were formulated considering all the parity orders. While formulating the equations, the following five variables were used: pre-farrowing body weight, piglets born, litter weight, the interval between pre-farrowing weighing and farrowing (in days), and the total feed intake between pre-farrowing and post-farrowing weighing. The seven models were compared using the sets of possible predictors through regression with the best subsets procedure (Minitab for Windows, v. 18). Equations (EQ) 1, 2, and 4 were validated with a database comprising 732 sows (parity orders: 1-5). The females were weighed on Day 107 of gestation and within 24 h after farrowing. The predicted weights estimated by EQ 2 and 4 (215.4 ± 34.3 kg and 216.7 ± 34.4 kg, respectively) did not significantly differ from the observed weight (216.8 ± 34.6 kg) [P > 0.05].[...]

Proposal of equations for predicting post-farrowing sow weigh

Background: Body condition score is used widely in swine production to ensure adequate nutritional levels in sows during gestation and lactation. However, body condition score is not a gold standard for the estimation of nutritional requirements in sows. Post-farrowing sow body weight assessment might serve as a useful approach for the better adjustment of the nutritional requirements during lactation; however, this approach is time-consuming, requires labor, and might result in detrimental effects on the sow behavior and welfare. The objective of the present study, therefore, was to formulate prediction equations for the estimation of post-farrowing sow weight.Materials, Methods & Results: Seven equations were formulated for predicting the post-farrowing sow body weight, by using the data from three databases, which comprised a total 522 sows (434 gilts and 88 multiparous). The sows were weighed on Day 112 of gestation and after farrowing within 12 h. The piglets birth weight was recorded within 24 h after farrowing. The equations were formulated considering all the parity orders. While formulating the equations, the following five variables were used: pre-farrowing body weight, piglets born, litter weight, the interval between pre-farrowing weighing and farrowing (in days), and the total feed intake between pre-farrowing and post-farrowing weighing. The seven models were compared using the sets of possible predictors through regression with the best subsets procedure (Minitab for Windows, v. 18). Equations (EQ) 1, 2, and 4 were validated with a database comprising 732 sows (parity orders: 1-5). The females were weighed on Day 107 of gestation and within 24 h after farrowing. The predicted weights estimated by EQ 2 and 4 (215.4 ± 34.3 kg and 216.7 ± 34.4 kg, respectively) did not significantly differ from the observed weight (216.8 ± 34.6 kg) [P > 0.05].[...](AU)

A smartphone-based apple yield estimation application using imaging features and the ANN method in mature period

Apple yield estimation using a smartphone with image processing technology offers advantages such as low cost, quick access and simple operation. This article proposes distribution framework consisting of the acquisition of fruit tree images, yield prediction in smarphone client, data processing and model calculation in server client for estimating the potential fruit yield. An image processing method was designed including the core steps of image segmentation with R/B value combined with V value and circle-fitting using curvature analysis. This method enabled four parameters to be obtained, namely, total identified pixel area (TP), fitting circle amount (FC), average radius of the fitting circle (RC) and small polygon pixel area (SP). A individual tree yield estimation model on an ANN (Artificial Neural Network) was developed with three layers, four input parameters, 14 hidden neurons, and one output parameter. The system was used on an experimental Fuji apple (Malus domestica Borkh. cv. Red Fuji) orchard. Twenty-six tree samples were selected from a total of 80 trees according to the multiples of the number three for the establishment model, whereby 21 groups of data were trained and 5 groups o data were validated. The R2 value for the training datasets was 0.996 and the relative root mean squared error (RRMSE) value 0.063. The RRMSE value for the validation dataset was 0.284 Furthermore, a yield map with 80 apple trees was generated, and the space distribution o the yield was identified. It provided appreciable decision support for site-specific management.(AU)

Relación entre las medidas biométricas y el peso corporal en ovinos de la raza Texel / Relationship between biometric measures and body weight in Texel sheep / Relação entre medidas biométricas e peso corporal em ovinos da raça Texel

Este estudio tuvo como objetivo evaluar la predicción del peso corporal de ovinos de la raza Texel, mediante regresión lineal y no lineal basado en las medidas del cuerpo de la circunferencia del pecho, longitud del cuerpo, cruz de la altura y la circunferencia escrotal, y para describir el comportamiento de crecimiento de las medidas en relación con el peso. Se utilizaron datos de 200 animales de Texel. Los datos fueron recolectados por técnicos capacitados para exposiciones agrícolas que tuvieron lugar en el estado de Paraná entre 2009 y 2014. Los datos para los machos y las hembras se analizaron por separado. Se determinó las correlaciones entre los rasgos. Todas estas características se correlacionaron significativamente, con la circunferencia que presenta mayor correlación con el peso corporal (r = 0,93 para los machos y r = 0,90 para las hembras). Entre los modelos estadísticos generados para la predicción de peso, lo que considera la circunferencia de pecho y la altura fueron los más acertados. La longitud del cuerpo no fue satisfactoria en la predicción. Al probar regresión no lineal, se observó que las mediciones biométricas mostraron un crecimiento alométrico negativo en relación con el peso corporal, lo que indica que estas medidas aumentan más rápido que el peso. Las medidas del cuerpo, en particular la circunferencia pueden ser usados como un método alternativo para la obtención de peso animal.(AU)

This study aimed to evaluate the prediction of body weight of Texel sheep, through linear and nonlinear regression, based on body measurements of chest girth, body length, withers height and scrotal circumference, and to describe the growth behavior of the measures in relation to the body weight. Data from 200 Texel sheep were used. Data were collected by trained technicians in agricultural exhibitions that took place in the state of Parana, Brazil between 2009 and 2014. The data for males and females were analyzed separately. It was determined the correlations between the measures and the weight. All these characteristics were significantly correlated, with the chest girth presenting the greater correlation with body weight (r = 0.93 for males and r = 0.90 for females). Among the statistical models generated for the prediction of body weight, the models which considered the chest girth and withers height were the most accurate. Body length was not satisfactory in the prediction. In the nonlinear regressions, it was observed that the biometric measures showed negative allometric growth in relation to body weight, indicating that these measures increase faster than weight. The body measurements, particularly the chest girth can be used as an alternative method for obtaining the animal body weight.(AU)

Objetivou-se avaliar a predição do peso corporal de ovinos da raça Texel, por meio de regressões lineares e não-lineares com base nas medidas corporais de perímetro torácico, comprimento corporal, altura de cernelha e circunferência escrotal, bem como descrever o comportamento do crescimento das medidas em relação ao peso. Foram utilizados dados de 200 animais da raça Texel. Os dados foram coletados por técnicos treinados durante exposições agropecuárias que ocorreram no estado do Paraná entre os anos de 2009 e 2014. Os dados de machos e fêmeas foram analisados separadamente. Determinou-se as correlações entre as características estudadas. Todas as características foram significativamente correlacionadas, com o perímetro torácico apresentando maior correlação com o peso corporal (r=0,93 para machos e r=0,90 para fêmeas). Dentre os modelos estatísticos gerados para a predição do peso, os que consideraram o perímetro torácico e altura foram os mais precisos. O comprimento corporal não foi satisfatório na predição. Ao se testar as regressões não-lineares, foi observado que as medidas biométricas apresentaram crescimento alométrico negativo em relação ao peso corporal, indicando que essas medidas aumentam mais rapidamente do que o peso.As medidas corporais, principalmente o perímetro torácico, podem ser usadas como método alternativo para obtenção de peso dos animais.(AU)

Relación entre las medidas biométricas y el peso corporal en ovinos de la raza Texel / Relationship between biometric measures and body weight in Texel sheep / Relação entre medidas biométricas e peso corporal em ovinos da raça Texel

Este estudio tuvo como objetivo evaluar la predicción del peso corporal de ovinos de la raza Texel, mediante regresión lineal y no lineal basado en las medidas del cuerpo de la circunferencia del pecho, longitud del cuerpo, cruz de la altura y la circunferencia escrotal, y para describir el comportamiento de crecimiento de las medidas en relación con el peso. Se utilizaron datos de 200 animales de Texel. Los datos fueron recolectados por técnicos capacitados para exposiciones agrícolas que tuvieron lugar en el estado de Paraná entre 2009 y 2014. Los datos para los machos y las hembras se analizaron por separado. Se determinó las correlaciones entre los rasgos. Todas estas características se correlacionaron significativamente, con la circunferencia que presenta mayor correlación con el peso corporal (r = 0,93 para los machos y r = 0,90 para las hembras). Entre los modelos estadísticos generados para la predicción de peso, lo que considera la circunferencia de pecho y la altura fueron los más acertados. La longitud del cuerpo no fue satisfactoria en la predicción. Al probar regresión no lineal, se observó que las mediciones biométricas mostraron un crecimiento alométrico negativo en relación con el peso corporal, lo que indica que estas medidas aumentan más rápido que el peso. Las medidas del cuerpo, en particular la circunferencia pueden ser usados como un método alternativo para la obtención de peso animal.

This study aimed to evaluate the prediction of body weight of Texel sheep, through linear and nonlinear regression, based on body measurements of chest girth, body length, withers height and scrotal circumference, and to describe the growth behavior of the measures in relation to the body weight. Data from 200 Texel sheep were used. Data were collected by trained technicians in agricultural exhibitions that took place in the state of Parana, Brazil between 2009 and 2014. The data for males and females were analyzed separately. It was determined the correlations between the measures and the weight. All these characteristics were significantly correlated, with the chest girth presenting the greater correlation with body weight (r = 0.93 for males and r = 0.90 for females). Among the statistical models generated for the prediction of body weight, the models which considered the chest girth and withers height were the most accurate. Body length was not satisfactory in the prediction. In the nonlinear regressions, it was observed that the biometric measures showed negative allometric growth in relation to body weight, indicating that these measures increase faster than weight. The body measurements, particularly the chest girth can be used as an alternative method for obtaining the animal body weight.

Objetivou-se avaliar a predição do peso corporal de ovinos da raça Texel, por meio de regressões lineares e não-lineares com base nas medidas corporais de perímetro torácico, comprimento corporal, altura de cernelha e circunferência escrotal, bem como descrever o comportamento do crescimento das medidas em relação ao peso. Foram utilizados dados de 200 animais da raça Texel. Os dados foram coletados por técnicos treinados durante exposições agropecuárias que ocorreram no estado do Paraná entre os anos de 2009 e 2014. Os dados de machos e fêmeas foram analisados separadamente. Determinou-se as correlações entre as características estudadas. Todas as características foram significativamente correlacionadas, com o perímetro torácico apresentando maior correlação com o peso corporal (r=0,93 para machos e r=0,90 para fêmeas). Dentre os modelos estatísticos gerados para a predição do peso, os que consideraram o perímetro torácico e altura foram os mais precisos. O comprimento corporal não foi satisfatório na predição. Ao se testar as regressões não-lineares, foi observado que as medidas biométricas apresentaram crescimento alométrico negativo em relação ao peso corporal, indicando que essas medidas aumentam mais rapidamente do que o peso.As medidas corporais, principalmente o perímetro torácico, podem ser usadas como método alternativo para obtenção de peso dos animais.

Artificial neural network for prediction of the area under the disease progress curve of tomato late blight

Artificial neural networks (ANN) are computational models inspired by the neural systems of living beings capable of learning from examples and using them to solve problems such as non-linear prediction, and pattern recognition, in addition to several other applications. In this study, ANN were used to predict the value of the area under the disease progress curve (AUDPC) for the tomato late blight pathosystem. The AUDPC is widely used by epidemiologic studies of polycyclic diseases, especially those regarding quantitative resistance of genotypes. However, a series of six evaluations over time is necessary to obtain the final area value for this pathosystem. This study aimed to investigate the utilization of ANN to construct an AUDPC in the tomato late blight pathosystem, using a reduced number of severity evaluations. For this, four independent experiments were performed giving a total of 1836 plants infected with Phytophthora infestans pathogen. They were assessed every three days, comprised six opportunities and AUDPC calculations were performed by the conventional method. After the ANN were created it was possible to predict the AUDPC with correlations of 0.97 and 0.84 when compared to conventional methods, using 50 % and 67 % of the genotype evaluations, respectively. When using the ANN created in an experiment to predict the AUDPC of the other experiments the average correlation was 0.94, with two evaluations, 0.96, with three evaluations, between the predicted values of the ANN and they were observed in six evaluations. We present in this study a new paradigm for the use of AUDPC information in tomato experiments faced with P. infestans. This new proposed paradigm might be adapted to different pathosystems.(AU)

Artificial neural network for prediction of the area under the disease progress curve of tomato late blight

Artificial neural networks (ANN) are computational models inspired by the neural systems of living beings capable of learning from examples and using them to solve problems such as non-linear prediction, and pattern recognition, in addition to several other applications. In this study, ANN were used to predict the value of the area under the disease progress curve (AUDPC) for the tomato late blight pathosystem. The AUDPC is widely used by epidemiologic studies of polycyclic diseases, especially those regarding quantitative resistance of genotypes. However, a series of six evaluations over time is necessary to obtain the final area value for this pathosystem. This study aimed to investigate the utilization of ANN to construct an AUDPC in the tomato late blight pathosystem, using a reduced number of severity evaluations. For this, four independent experiments were performed giving a total of 1836 plants infected with Phytophthora infestans pathogen. They were assessed every three days, comprised six opportunities and AUDPC calculations were performed by the conventional method. After the ANN were created it was possible to predict the AUDPC with correlations of 0.97 and 0.84 when compared to conventional methods, using 50 % and 67 % of the genotype evaluations, respectively. When using the ANN created in an experiment to predict the AUDPC of the other experiments the average correlation was 0.94, with two evaluations, 0.96, with three evaluations, between the predicted values of the ANN and they were observed in six evaluations. We present in this study a new paradigm for the use of AUDPC information in tomato experiments faced with P. infestans. This new proposed paradigm might be adapted to different pathosystems.

Logistic growth models of China pinks, cultivated on seven substrates, as a function of degree days / Modelo logístico de crescimento de cravina de jardim cultivada em sete substratos em função da soma térmica

The objective of this study was to characterize the height (H) and leaf number (LN) of China pinks, grown in seven substrates, as a function of degree days, using the logistic growth model. H and LN were measured from 56 plants per substrate, for 392 plants in total. Plants that were grown on substrates formed of 50% soil with 50% rice husk ash (50% S + 50% RH) and 80% rice husk ash with 20% worm castings (80% RH + 20% W) had the longest vegetative growth period (74d), corresponding to 1317.9ºCd. The logistic growth model, adjusted for H, showed differences in the estimation of maximum expected height () between the substrates, with values between 10.47cm for 50% S + 50% RH and 35.75cm for Mecplant(r). When was estimated as LN, variation was also observed between the different substrates, from approximately 30 leaves on plants growing on 50% S + 50% RH to 34 leaves on the plants growing on the substrate formed of 80% RH + 20% W. Growth of China pinks can be characterized using H or LN in the logistic growth model as a function of degree days, being the provided plants adequately fertilized. The best substrates in terms of maximum height and leaf number were 80% soil + 20% worm castings and Mecplant(r). However, users must recalibrate the model with the estimated parameters before applying it to different growing conditions.(AU)

O objetivo do estudo foi caracterizar a altura (H) e o número de folhas (NF), pelo modelo logístico, de cravina de jardim cultivada em sete substratos em função da soma térmica. Foram avaliadas a H e o NF de 56 plantas por substrato, totalizando 392 plantas ajustadas. As plantas dos substratos compostos de: 50% de solo e 50% de cinzas de casca de arroz (50% S + 50% CA); e 80% cinzas de casca de arroz e 20% húmus de minhoca (80% CA + 20% H) tiveram o maior ciclo, de 74 dias, e o completaram com soma térmica de 1317,9ºC dia. O modelo logístico ajustado para H apresentou diferenças para a estimativa da altura máxima esperada (α) entre os substratos, com valores de 10,47cm para 50% S + 50% CA e, 35,75cm, para o substrato Mecplant(r). Para o NF, observou-se que teve menor variação entre os substratos, desde aproximadamente 30 folhas, nas plantas do substrato 50% S + 50% CA até 34 folhas, nas plantas do substrato 80% CA + 20% H. O crescimento de cravina de jardim, a partir das variáveis estudadas, pode ser caracterizado pelo modelo logístico, em função da soma térmica acumulada, quando as plantas estão sem restrições nutricionais. Considerando a altura máxima e o número máximo de folhas, os melhores substratos foram o composto de 80% de solo + 20% húmus de minhoca e o Mecplant(r). Entretanto, os usuários devem testar as calibrações do modelo, com os parâmetros sugeridos, antes de aplicar o modelo para outras condições climáticas.(AU)

Predictive factors of species composition of follower fishes in nuclear-follower feeding associations: a snapshot study

We tested whether habitat, identity, size of nuclear fishes, and intensity of bottom disturbance caused by their foraging can predict the composition of fish followers in nuclear-follower feeding associations. The study was carried out in a stream of the Serra da Bodoquena, Mato Grosso do Sul State, Southwestern Brazil. We performed underwater observational sessions (total 12 h) of such interspecific interactions to obtain data about the identity and abundance of the followers in the association, as well as the identity and size of the nuclear fish. We also evaluated whether different intensities of bottom disturbance due to the nuclear fish foraging and type of habitat may influence interactions. We recorded 38 episodes involving nuclear and follower species. Using a multivariate analysis with distance matrices, we noted that the intensity of bottom disturbance caused by nuclear fishes was the main predictor of the composition of the follower species (r = 0.55, p < 0.01), as well as the identity of the nuclear species, although this latter relation was weak (r = 0.09, p = 0.05). Such results indicate that followers react readily to sediment suspension, which reflects the trophic plasticity and opportunistic foraging characteristic of most tropical freshwater fishes.(AU)

Neste estudo testamos se o hábitat, a identidade e o tamanho da espécie nuclear, bem como a intensidade do distúrbio causado pela atividade do nuclear podem predizer a composição de seguidores na associação alimentar do tipo nuclear-seguidor. O estudo foi conduzido em um riacho da Serra da Bodoquena, estado do Mato Grosso do Sul, bacia do alto Rio Paraguai. Foram realizadas sessões de observação subaquática (totalizando 12 h), visando a obter informações sobre identidade e abundância dos seguidores, assim como identidade e tamanho da espécie nuclear, hábitat e intensidade do distúrbio causado pela atividade de forrageamento da espécie nuclear. Foram registradas 38 associações envolvendo cinco espécies nucleares e nove espécies seguidoras. A análise multivariada com matrizes de distância demonstrou que a intensidade do distúrbio causado pelos nucleares foi o principal preditor da composição de seguidores (r = 0,55, p < 0,01), assim como a identidade da espécie nuclear, embora essa relação tenha sido fraca (r = 0,09, p = 0,05). Esses resultados indicam que os seguidores respondem prontamente à suspensão de sedimento, refletindo a plasticidade trófica e o oportunismo de forrageio característico da maioria dos peixes tropicais de água doce.(AU)

Uso de modelos lineares mistos na avaliação genética de escores visuais: estudo de simulação / Using linear mixed models in genetic evaluation of visual scores: simulation study

Objetivou-se avaliar a aplicação da metodologia de modelos lineares mistos em características de escores visuais por meio de simulação, considerando-se duas estruturas populacionais (com e sem seleção), dois níveis de herdabilidade (0,1 e 0,4) e quatro níveis de conectabilidade (8, 20, 38 e 60 por cento). As populações com e sem seleção estavam constituídas por 6660 e 3360 animais, respectivamente, dos quais os últimos 2460 animais tinham fenótipo para o escore visual. Assumiu-se uma variável contínua adjacente ao escore visual, a partir da qual foram definidos os intervalos correspondentes a cada categoria de escore visual. O processo de simulação foi feito por meio do software R, e a estimação de parâmetros e predição de valores genéticos pelo software Wombat, sob modelo animal, considerando-se modelos com e sem efeitos fixos. Os critérios de avaliação foram: o erro quadrático médio (EQM) para a herdabilidade e as correlações de Spearman entre os valores genéticos verdadeiros e preditos. As estimativas da herdabilidade apresentaram-se próximas do valor verdadeiro nos cenários sem seleção (0,084-0,101 e 0,367-0,389), no entanto este resultado não ocorreu quando houve seleção, pois a herdabilidade apresentou-se subestimada (0,032 e 0,278). As correlações apresentaram-se maiores nos cenários sem seleção e com herdabilidade de 0,4 (0,86-0,89). Em todos os cenários simulados, a inclusão do efeito fixo no modelo melhorou as estimativas de herdabilidade e as correlações entre os valores genéticos verdadeiros e preditos. O nível de conectabilidade afetou a correção dos efeitos fixos feita pela atribuição dos escores. Em conclusão, a metodologia dos modelos lineares mistos pode ser utilizada na estimação de parâmetros e predição de valores genéticos de escores visuais em populações sem seleção, entretanto não se apresenta adequada em populações sob seleção.(AU)

This study aimed to evaluate the application of linear mixed models methodology using simulated data for trait visual scores, two population structures (with and without selection), two levels of heritability (0.1 and 0.4) and four levels of connectability (8, 20, 38 and 60 percent) were examined. Populations with and without selection consisted of 6,660 and 3,360 animals respectively, of which, the last in 2460 had score visual phenotypes. The scores were simulated with an underlying normal distribution from which intervals were defined corresponding to each category of the visual scores. The simulation process was performed in software R, to estimate genetic parameters and predict breeding values through software Wombat using animal model, considering models with and without fixed effects. The evaluation criteria were: the mean squared error (EQM) for heritability and Spearman correlations between true and predicted breeding values. Estimates of heritability showed close to the true value in scenarios without selection (0.084-0.101 and 0.367-0.389), however when selection was applied heritability was underestimated (0.032 and 0.278). Consistent with heritability, the correlations were higher for the scenarios without selection and with heritability of 0.4 (0.86-0.89). In all scenarios simulated the inclusion of fixed effects in the model improved the estimates of heritability and correlations between true and predicted breeding values. The level of connectability affected the correction of fixed effects done by allocating visual scores. The linear mixed model methodology can be used in the estimation of genetic parameters and predicted breeding values for visual scores in populations without selection, however, is not suiting in populations under selection.(AU)

Consumo alimentar residual como critério de seleção para eficiência alimentar / Residual feed intake as a criteria for feed efficiency selection

O consumo alimentar residual é uma medida de eficiência alimentar independente do crescimento e do peso à maturidade. O melhoramento genético, ao utilizar o consumo alimentar residual como critério de seleção, poderia reduzir os custos com alimentação, haja vista as diferenças existentes na ingestão de matéria seca dos animais com o mesmo ganho médio diário em peso. Frente às vantagens da sua utilização em programas de melhoramento genético, o alto custo para sua determinação limita sua adoção, pois é necessária a coleta individual dos dados de ingestão de alimentos dos animais. Além disso, o conhecimento incompleto dos mecanismos biológicos relacionados ao aumento da eficiência alimentar dificulta a identificação e posterior seleção dos animais de genética superior. Esta revisão aborda aspectos gerais do consumo alimentar residual enfocando as metodologias de predição do consumo de matéria seca e a utilização dos hormônios leptina e IGF-I como indicadores fisiológicos e marcadores moleculares na tentativa de identificar animais eficientes.

The residual feed intake is a measure of feed efficiency independent growth and weight at maturity. Genetic improvement by using the residual feed intake as a selection criterion, could to reduce feed costs, due differences in dry matter intake of animals with the same average daily gain in weight. Against the advantages of its use in breeding programs, the high cost for their determination limits its adoption, it is necessary to collect data from individual feed intake of animals. Furthermore, the incomplete knowledge of biological mechanisms related to increase feed efficiency complicates the identification and subsequent selection of animals for genetic studies. This review covers general aspects of residual feed intake focusing on the methodologies for predicting dry matter intake and the use of leptin and IGF-I as indicators of physiological and molecular markers in an attempt to identify efficient animals.

Consumo alimentar residual como critério de seleção para eficiência alimentar / Residual feed intake as a criteria for feed efficiency selection

O consumo alimentar residual é uma medida de eficiência alimentar independente do crescimento e do peso à maturidade. O melhoramento genético, ao utilizar o consumo alimentar residual como critério de seleção, poderia reduzir os custos com alimentação, haja vista as diferenças existentes na ingestão de matéria seca dos animais com o mesmo ganho médio diário em peso. Frente às vantagens da sua utilização em programas de melhoramento genético, o alto custo para sua determinação limita sua adoção, pois é necessária a coleta individual dos dados de ingestão de alimentos dos animais. Além disso, o conhecimento incompleto dos mecanismos biológicos relacionados ao aumento da eficiência alimentar dificulta a identificação e posterior seleção dos animais de genética superior. Esta revisão aborda aspectos gerais do consumo alimentar residual enfocando as metodologias de predição do consumo de matéria seca e a utilização dos hormônios leptina e IGF-I como indicadores fisiológicos e marcadores moleculares na tentativa de identificar animais eficientes.(AU)

The residual feed intake is a measure of feed efficiency independent growth and weight at maturity. Genetic improvement by using the residual feed intake as a selection criterion, could to reduce feed costs, due differences in dry matter intake of animals with the same average daily gain in weight. Against the advantages of its use in breeding programs, the high cost for their determination limits its adoption, it is necessary to collect data from individual feed intake of animals. Furthermore, the incomplete knowledge of biological mechanisms related to increase feed efficiency complicates the identification and subsequent selection of animals for genetic studies. This review covers general aspects of residual feed intake focusing on the methodologies for predicting dry matter intake and the use of leptin and IGF-I as indicators of physiological and molecular markers in an attempt to identify efficient animals.(AU)