ABSTRACT
Morphological similarity, resource sharing, and differences in habitat use by species are factors that favor their coexistence. The objective of this study was to test possible differences in ecomorphology and diet composition of two Heptapterids (Imparfinis mirini and Cetopsorhamdia iherengi) to identify patterns related to resource use. Samplings were carried out in ten streams in Southern Brazil and 123 individuals were caught. A total of 21 ecomorphological indices were calculated for each individual and the volumetric and occurrence methods were used to quantify stomach contents. Both species presented significant differences in some ecomorphological traits, mainly related to foraging behavior. Even though both species were considered insectivorous, the consumed feeding resources differed between them. Cetopsorhamdia iheringi diet was dominated by Simuliidae and terrestrial Coleoptera larvae, while Imparfinis mirini, presented a diet dominated mainly by Trichoptera larvae, Ephemeroptera nymph, and Annelida. Although ecomorphological patterns cannot be used as an absolute factor to explain diet variations, they provide relevant information about how species share resources. These mechanisms allow us to obtain important subsidies for the conservation and management of freshwater ecosystems since they provide an effective understanding on the interactions that occur between the species.
Subject(s)
Animals , Trophic Levels , Catfishes/anatomy & histology , Catfishes/growth & developmentABSTRACT
El maíz (Zea mays L.) posee un genoma complejo y una amplia diversidad genética. La información de caracteres fenotípicos y marcadores moleculares en su conjunto provee una mejor descripción e interpretación de la variabilidad genética. El objetivo del trabajo fue estimar la diversidad genética y caracterizar fenotípicamente un panel de 291 líneas de maíz de CIMMYT. Las líneas corresponden a ocho grupos establecidos de acuerdo a su adaptación ambiental y origen geográfico. Éstas se evaluaron fenotípicamente por medio de nueve caracteres agro-morfológicos en tres ambientes del sur de la provincia de Córdoba, Argentina. El intervalo antesis-estigma (IAE) presentó la mayor variabilidad fenotípica. El 40% de las líneas de maíz registraron un IAE menor a cinco días, indicando buena adaptación a los ambientes de evaluación. La estructura poblacional dada por los subgrupos de adaptación ambiental es sólo un factor menor que contribuye a la variabilidad fenotípica del panel estudiado. El análisis de componentes principales (ACP) permitió obtener el ordenamiento fenotípico y el genotípico, mientras que el análisis de procrustes generalizado indicó un consenso del 60% entre ambos ordenamientos para el total de líneas. El consenso entre el ordenamiento obtenido con caracteres agro-morfológicos y con marcadores moleculares indica desequilibrio de ligamiento entre los SNPs y los genes que controlan los caracteres agro-morfológicos. Los resultados muestran una amplia diversidad genética en el germoplasma evaluado, lo que sugiere que esta colección de líneas es un recurso importante para impulsar ganancias genéticas futuras en los programas de mejoramiento de maíz de Argentina.
CIMMYT maize inbred lines (CMLs) are freely distributed to breeding programs around the world. Better information on phenotypic and genotypic diversity may provide guidance to breeders on how to use more efficiently the CMLs in their breeding programs. In this study a group of 291 CIMMYT maize inbred lines, was phenotyped by nine agro-morphological traits in south Córdoba, Argentina and genotyped using 18,082 SNPs. Based on the geographic information and the environmental adaptation, 291 CMLs were classified into eight subgroups. Anthesis-silking interval (IAE) was the trait with higher phenotypic diversity. A 40% of maize inbred lines, with IAE less than five days, show a good adaptation to growing conditions in south Córdoba, Argentina. The low phenotypic variation explained by environmental adaptation subgroups indicates that population structure is only a minor factor contributing to phenotypic diversity in this panel. Principal component analysis (ACP) allowed us to obtain phenotypic and genotypic orderings. Generalized procrustes analysis (APG) indicated a 60% consensus between both data type from the total panel of maize lines. In each environmental adaptation subgroup, the APG consensus was higher. This result, which might indicate linkage disequilibrium between SNPs markers and the genes controlling these agro-morphological traits, is promising and could be used as an initial tool in the identification of Quantitative Trait Loci (QTL). Information on genetic diversity, population structure and phenotypic diversity in local environments will help maize breeders to better understand how to use the current CIMMYT maize inbred lines group.
ABSTRACT
Aims: To examine the possible influence of varying altitudes on the morphological traits-based phenotypic variability in Bidens pilosa L. Study Design: Randomly selected plants from each natural region. Place and Duration of Study: Three natural regions of Burundi, i.e. IMBO (842 m), KIRIMIRO (1645 m), and MUGAMBA (2075 m), between November 2015 and May 2016. Methodology: We randomly selected 36 plants (12 plants from each of the three sites of seed sowing and plant development) for which we measured plant life cycle stages such as the period of germination, the period of leaf formation, flowering period, fruit formation period and complete maturity period. Plant height, internode length, leaf length, leaf width, inflorescence length, achene length, inflorescence number, node number, achene number per inflorescence and achene number per plant, after plant complete maturity were also recorded. Obtained data were statistically analyzed. Results: Bidens pilosa from IMBO (842 m) showed the lowest periods of germination, leaf formation, flowering, fruit formation and complete maturity, while longest periods were observed in MUGAMBA (2075 m) region. In addition, one-way analysis of variance showed that phenotypic variation in Bidens pilosa was highly significant within and across populations (P = 0.000) for the studied quantitative morphological traits except the achene number/inflorescence (P = .887). Some traits increased with increase in altitude while others decreased with increase in altitude. Moreover, internode length, leaf length, inflorescence number and achene number per plant significantly differentiated the three populations from the three regions (P < 0.01). Cluster analysis revealed also that IMBO (842 m) population was different from KIRIMIRO (1645 m) and MUGAMBA (2075 m) which are tending to be closer. Conclusion: Altitudes significantly influenced phenotypic variability of Bidens pilosa. However, further studies on a wide range of morphological traits and altitudes are needed as well as biochemical and molecular analyses.
ABSTRACT
The aim of this study was to analyze the sexual dimorphism in the mandibles of Jordanians and derive a population specific equation for sex prediction. The employed sample comprised 270 cone beam computed tomography (CBCT) images of Jordanians (147 males and 123 females) aged 27-55 years. The images were rendered to 3D surface models, using customized software that provided various views for each mandible, on which measurements made of nine parameters (ramus height, right and left coronoids height, mandibular length, gonial angle, Intergonial breadth, Intercondylar breadth, mental and mandibular foramena) for the analysis of sex identification. The collected data sets were treated statistically using the Statistical Package SPSS version-21. Canonical discriminant function analysis was used to specify a parameter or combination of parameters that best separate the two sexes. Stepwise analysis together with leave-one-out classification procedure was applied (utilizing the Wilks lambda method), which identified six parameters that formed the best combination most precisely predicting sex. It also identified the predictors' coefficients from which a predictive equation for the Jordanian population was derived. The discriminant function group centroid discriminant scores for males and females and the sectioning cut-score were also defined. According to the equation, the function score for any set of measurements that is above the cut score is probably for a male individual whereas a score that was below the cut score is probably for a female subject.
El objetivo de este estudio fue analizar el dimorfismo sexual en las mandíbulas de los jordanos y derivar una ecuación específica de la población para la predicción del sexo. La muestra consistió en 270 imágenes de tomografía computarizada de haz cónico (CBCT) de jordanos (147 hombres y 123 mujeres) con edades entre los 27 y 55 años. Las imágenes se representaron en modelos de superficie 3D, utilizando software personalizado que proporcionó varias imágenes para cada mandíbula, en las que se midieron nueve parámetros (altura de la rama, altura de los procesos coronoides derecho e izquierdo, longitud mandibular, ángulo gonial, amplitud intergonial, amplitud intercondilar y foramen mandibular) para el análisis de la identificación de sexo. Los conjuntos de datos recopilados se trataron estadísticamente utilizando el programa estadístico SPSS versión-21. El análisis de función discriminante canónica se utilizó para especificar un parámetro, o una combinación de parámetros que separaran mejor los dos sexos. Se aplicó el análisis por pasos junto con el procedimiento de clasificación de dejar salir uno (utilizando el método de Wilks lambda), que identificó seis parámetros que formaban la mejor combinación que predecía con mayor precisión el sexo. También se identificó los coeficientes de los predictores a partir de los cuales se obtuvo una ecuación predictiva para la población jordana. Se definieron además, los puntajes discriminantes centroide del grupo para hombres y mujeres, además del puntaje de corte seccional. De acuerdo con la ecuación, el puntaje de la función para cualquier conjunto de medidas que está por encima del puntaje de corte es probablemente para un individuo masculino, mientras que un puntaje que estaba por debajo del puntaje de corte, probablemente era femenino.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Sex Characteristics , Mandible/anatomy & histology , Mandible/diagnostic imaging , Discriminant Analysis , Cone-Beam Computed Tomography , JordanABSTRACT
ABSTRACT We studied the volatile composition and sexual morphs of Nephelium lappaceum flowers from two orchards, and investigated the choice behavior of the honey bee, Apis mellifera toward the floral extracts from both locations. Our results showed significant differences in chemical composition and sexual morphs; only the hermaphrodite flowers from the Herradero orchard produced limonene and α-pinene and had longer peduncle and sepal than flowers from the Metapa orchard; on the other hand, the hermaphrodite flowers from the Metapa orchard had longer gynoecium. In the behavioral experiment the extracts from the Herradero orchard seemed to give A. mellifera foragers better cues for orientation to food sources, perhaps due to the presence of limonene and α-pinene, which are absent in the samples from Metapa. Such differences in both orchards could affect pollinator attraction and ultimately seed set and productivity.
ABSTRACT
SUMMARY: The aim of the study was to determine various morphological characteristics from birth to the age of 150th day of Boer x Hair goat F1 crossbred (BH) kids and pure Hair goat (HG) kids raised in semi-intensive conditions and reveal factors such as the effects of genotype, dam age, dam's live weight, year, birth type and sex on this parameter. This study was applied between the years 2011-2012 in Çatak in the Van region and between the years 2013-2014 at the Yuzuncu Yil University Research and Practice Farm. Various body measurements; wither height, back height, rump height, sacrum height, body length, chest length, chest depth, chest circumference, circumference of leg, cannon bone circumference, chest width, front-rump width, mid-rump width were determined 29.8, 28.4, 28.7, 26.2, 28.7, 17.0, 13.3, 30.4, 26.9, 5.2, 5.9, 6.0, and 8.7 cm at birth, respectively; 43.8, 43.8, 44.6, 40.6, 43.6, 22.2, 19.3, 51.7, 41.4, 6.6, 9.2, 9.3, and 11.3 cm at 60th day, respectively; 56.1, 53.4, 54.4, 47.5, 53.3, 27.3, 24.1, 61.4, 49.6, 7.3, 10.6, 11.1, and 13.2 cm at 150th day, respectively for BH kids; 27.3, 25.9, 29.3, 25.3, 27.1, 15.9, 12.3, 29.0, 21.3, 5.1, 5.0, 5.6, and 7.4 cm at birth, respectively; 40.4, 40.1, 42.9, 37.6, 40.5, 22.3, 18.4, 48.1, 36.4, 6.0, 7.9, 9.1, and 10.8 cm at 60th day, respectively; 50.3, 49.2, 51.0, 45.7, 50.4, 27.5, 22.9, 57.3, 43.4, 6.5, 9.5, 10.7, and 11.9 cm at 150th day, respectively for HG kids. When all of the data was considered, it was concluded that the BH kids are much better than the HG kids for both morphological and zoometric values.
RESUMEN: El objetivo del estudio fue determinar varias características morfológicas desde el nacimiento hasta la edad de 150 días en caprinos Boer x Hair goat F1 crossbred (BH) y Cabra pura (HG) criados en condiciones semi-intensivas y revelar factores tales como los efectos del genotipo, la edad, el peso vivo de la el tipo de nacimiento y el sexo entre otros. Este estudio fue realizado entre los años 2011-2012 en Çatak, región de Van y entre los años 2013-2014 en la Granja de Investigación y Práctica de la Universidad Yuzuncu Yil. Se estudiaron diversas medidas corporales: Altura del talón, altura de la espalda, altura de la grupa, altura del sacro, longitud del cuerpo, longitud del pecho, profundidad del tórax, circunferencia del pecho, circunferencia de la pierna, circunferencia del hueso del cañón, ancho del pecho, ancho de la grupa delantera y anchura media de la grupa, así se determinaron 29.8, 28.4, 28.7, 26.2, 28.7, 17.0, 13.3, 30.4, 26.9, 5.2, 5.9, 6.0 y 8.7 cm al nacer, respectivamente; 43.8, 43.8, 44.6, 40.6, 43.6, 22.2, 19.3, 51.7, 41.4, 6.6, 9.2, 9.3 y 11.3 cm en el 60º día, respectivamente; 56.1, 53.4, 54.4, 47.5, 53.3, 27.3, 24.1, 61.4, 49.6, 7.3, 10.6, 11.1 y 13.2 cm en 150 días, respectivamente para niños BH; 27.3, 25.9, 29.3, 25.3, 27.1, 15.9, 12.3, 29.0, 21.3, 5.1, 5.0, 5.6 y 7.4 cm al nacimiento, respectivamente; 40,4, 40,1, 42,9, 37,6, 40,5, 22,3, 18,4, 48,1, 36,4, 6,0,7,9, 9,1 y 10,8 cm en el 60º día, respectivamente; 50.3, 49.2, 51.0, 45.7, 50.4, 27.5, 22.9, 57.3, 43.4, 6.5, 9.5, 10.7 y 11.9 cm a los 150 días, respectivamente, para cabritos HG. Cuando se consideraron todos los datos, se concluyó que los cabritos BH son mucho mejores que los cabritos HG para los valores morfológicos y zoométricos.
Subject(s)
Animals , Goats/anatomy & histologyABSTRACT
Pod fly, Melanagromyza obtusa is an important emerging pest and a major constraint to increase the production and productivity of pigeonpea. The concealed mode of life of pod fly within the pod makes it difficult to control. Hence, host plant resistance is an important tool for the management of this pest. Therefore, a set of forty genotypes were screened for resistance to pod fly under field conditions and characterized for morphological and biochemical traits in the pods. The correlation studies revealed that, among morphological and biochemical constituents of pigeonpea, pod length (r=0.389*), pod width (r=0.380*), protein content (r=0.857**), total carbohydrates (r=0.782**), reducing sugars (r=0.848**) and total free amino acids (r=0.832**) in the pod walls were positively correlated with per cent pod damage, whereas pod wall thickness (r= -0.762**), trichome density (r= -0.745**) and phenol content (r= -0.871**) had significant negative correlation with pod fly damage. Therefore, these traits can be used as phenotypic and biochemical markers to identify pigeonpea genotypes with resistance to M. obtusa, and use in pod fly resistance breeding program.
ABSTRACT
The genetic diversity of a set of 21 hexaploid wheat germplasm from the National Agronomic Institute of Tunisia were investigated by applying 26 agro morphological traits and 10 wheat microsatellites molecular markers (Simple Sequence Repeat). The morphological variability was analyzed using the Principal Component Analysis (PCA) and the cluster analysis based on ward's method and square Euclidean distance. Eighteen microsatellites primer pairs were tested for all genotypes, among them 10 primers generated polymorphic and reproducible profiles. They revealed a total of 414 reducible bands among which 373 were polymorphic. The polymorphic information content (PIC) values per locus varied from 0,33 to 0,94 with an average of 0,72. Genetic similarity values between genotypes, calculated by the molecular derived data, were used to produce a dendrogram. The genotypes were clustered in four clear groups according to their origin, pedigree and in some cases to phenotypic characters similarities.
A diversidade genética de um conjunto de 21 hexaplóides em germoplasma de trigo oriundo do Instituto Nacional da Tunísia foi investigada pela aplicação de 26 caracteres morfológicos e 10 marcadores de microsatélites (Sequências simples repetidas). A variabilidade morfológica foi analisada pelo uso da análise de componentes principais (ACP) e análise de agrupamento baseada no método de Ward e o quadrado da distância Euclidiana. Dezoito primers de microsatélites foram testados para todos os genótipos, entre os quais 10 geraram polimorfismo e grupos distintos. Eles demonstraram um total de 414 bandas entre as quais 373 foram polimórficas. Os valores de polimorfismo encontrados por locus (VPL) variaram entre 0,33 a 0,94 com uma média de 0,72. Os valores da similaridade genética calculada para os dados moleculares originaram um dendograma. Os genótipos foram agrupados em quatro grupos de acordo com sua origem, pedigree (descendência) e em alguns casos pelos caracteres da similaridade fenotípica.
Subject(s)
Genetic Variation , Triticum , Microsatellite Repeats , GenotypeABSTRACT
The objective of this study was to verify the occurrence of Dioscorea trifida in Brazil and to obtain information concerning its distribution, management and diversity. Farmers from 21 communities were interviewed in the states of São Paulo, Santa Catarina and Mato Grosso. During the visits, semi-structured interviews were conducted to collect socio-economic, management and diversity data for this crop. Fifty-one collected accessions, plus two accessions obtained at local markets of Amazonas, were characterized using 12 morphological traits. Most the interviewed farmers were men (75%) with a mean age of 59.5 years. Just a few young people and labor force were available for agricultural activities, with an average of only three individuals per farm. Most farmers (56%) grew only one variety of D. trifida, although 44% had more than one variety in their fields, which aims to provide greater assurance at harvest. Many popular names were observed for D. trifida, and cará roxo (purple yam) was the name most used by farmers (43.4%). Characters referring to the tuber, such as skin and flesh color, were most relevant for the distinction of the accessions. The results of this study may collaborate to develop strategies for conservation, both ex situ and in situ, within the view of on farm conservation.
O objetivo deste trabalho foi verificar a ocorrência de Dioscorea trifida no Brasil e obter informações a respeito da sua distribuição, manejo e diversidade. Para tanto, foram visitados e entrevistados agricultores de 21 comunidades, nos Estados de São Paulo, Santa Catarina, Mato Grosso. Durante as visitas, foram realizadas entrevistas semi-estruturadas visando obter dados sócioeconômicos, de manejo e diversidade da cultura. Cinquenta e um acessos, além de dois acessos adquiridos em feiras no Estado do Amazonas, foram caracterizados por meio de 12 descritores morfológicos. A maioria dos entrevistados era homem (75%) com média de idade de 59,5 anos. Observou-se um número reduzido de jovens e mão de obra disponível para as atividades agrícolas, cerca de três indivíduos por roça. A maior parte dos agricultores (56%) cultiva apenas uma variedade de D. trifida, embora 44% tenham declarado o cultivo de mais de uma variedade, procedimento que visa dar maior garantia de colheita. Vários nomes populares foram observados para D. trifida, sendo cará roxo, a denominação mais utilizada pelos agricultores (43,4%). Os caracteres referentes às túberas, como cor da casca e da polpa, foram os mais relevantes para a distinção dos acessos. Os resultados obtidos poderão colaborar para elaborar estratégias de conservação, tanto ex situ como in situ, dentro da visão de conservação on farm.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Biodiversity , Crops, Agricultural , Dioscorea/classification , Brazil , Dioscorea/anatomy & histology , Farmers/statistics & numerical data , Socioeconomic FactorsABSTRACT
The main aim of this study was to estimate phenotypic correlations among live weight, withers height, rump height, chest depth, chest width, thoracic girth, body length, hip widths (between iliac tuberosities and between ischial tuberosities) and forelimb cannon perimeter with antler length measured during the growth of marals on a Kazakh farm. The data comprised 18 animals studied during their growth (at 18 months and at 24 months). In maral, the first period of antler productivity takes place at the age of 24 months. This fact should be taken into account in order to select the best animals for antler production, which is the main purpose for farming this species.
El objetivo de este estudio fue estimar en ciervos colorados de una granja de Kazajstán, las correlaciones fenotípicas entre el peso vivo, altura a la cruz, la profundidad del pecho, ancho de pecho, circunferencia torácica, longitud del cuerpo, ancho de cadera (entre tuberosidades ilíacas e isquiáticas) y perímetro del miembro anterior, con el largo de cuernos medido durante su crecimiento. Los datos de este estudio comprendieron 18 animales durante su crecimiento (entre los 18 y 24 meses). En el ciervo colorado el período inicial de la productividad de cuernos tiene lugar a los de 24 meses de edad. Este hecho se debe tener en cuenta para seleccionar los mejores animales para la producción de cuernos, objetivo principal para la crianza de esta especie.
Subject(s)
Animals , Male , Phenotype , Deer/anatomy & histology , Horns/anatomy & histologyABSTRACT
In cowpea, dual purpose plant types are more preferable for cultivation. Therefore, exotic and indigenous cowpea germplasm lines were evaluated in augmented design to study estimates of the correlation coefficients and path analysis of morphological as well as fodder and grain yield attributes. The present study showed a high impact of direct effects of correlation (0.9714**) and suggested that going for plant types with higher biomass per plant (0.8856**), dry weight per plant (0.4598), stem girth (0.2336) number of secondary branches (0.2788), leaves per plant (0.3251), pods per plant (0.9059) and pod clusters per plant (0.7718) would be effective for improving both fodder and seed yield in cowpea.
ABSTRACT
Morphological differences between two close fish populations were investigated in Doma Dam, north central Nigeria using principal component and discriminant analyses. The purpose was to identify the two species correctly and assign them into distinct genetic groups. To achieve this, seven morphometric measurements (body weight, standard length, total length, head length, body depth, dorsal fin length and caudal fin length) were made on each of the studied 252 fish specimens (153 Oreochromis niloticus and 99 Lates niloticus). The analysis of variance showed that significantly (P<0.05) higher values were recorded for Lates niloticus in all the body traits examined, except dorsal fin length. From the principal component analysis, the differences between the species resulted mainly from dorsal fin length, body weight, caudal fin length and head length. The stepwise discriminant analysis revealed that standard length, dorsal fin length and caudal fin length were the three most discriminating variables useful to distinguish clearly the two species at mature age. These three variables with strong discriminating power correctly classified 98.0 percent of individuals from the sample of known-fish populations. The classification accuracy was cross-validated using split-sample method, and indicated a 97.6 percent success rate (98.0 percent of Oreochromis niloticus and 97.0 percent of Lates niloticus were correctly assigned). The results can provide a sound scientific basis for the effective management and sustainable exploitation of the genetic resources of the two species under subtropical conditions.
Las diferencias morfológicas entre dos poblaciones de peces similares se han investigado en Doma Dam, centro-norte de Nigeria utilizando análisis de componentes principales y análisis discriminante. El propósito fue identificar correctamente las dos especies y asignarlas a los distintos grupos genéticos. Para lograr esto, siete medidas morfométricas (peso corporal, longitud estándar, longitud total, longitud de la cabeza, profundidad del cuerpo, longitud de la aleta dorsal y la longitud de la aleta caudal) se realizaron en cada una de las muestras de los 252 peces estudiados (153 Oreochromis niloticus y 99 Lates niloticus) . El análisis de varianza mostró que de forma significativa (p<0,05) los valores más altos se registraron en Lates niloticus, en todos los rasgos del cuerpo examinado con excepción de la longitud de la aleta dorsal. A partir del análisis de componentes principales, las diferencias entre las especies se observó principalmente en la longitud de la aleta dorsal, el peso corporal, la longitud de la aleta caudal y longitud de la cabeza. El análisis discriminante reveló que la longitud estándar, longitud aleta dorsal y caudal son las tres variables más discriminatorias de utilidad para distinguir claramente las dos especies en la edad madura. Estas tres variables con fuerte poder de discriminación clasificaron correctamente el 98,0 por ciento de los individuos de la muestra de las poblaciones conocidas de peces. La exactitud de la clasificación fue sometida a una validación cruzada utilizando el método de la muestra dividida, la que indicó una tasa de éxito del 97,6 por ciento (98,0 por ciento de Oreochromis niloticus y 97,0 por ciento de Lates niloticus asignados correctamente). Los resultados pueden proporcionar una base científica sólida para el manejo eficaz y la explotación sostenible de los recursos genéticos de las dos especies en condiciones subtropicales.
Subject(s)
Animals , Cichlids/anatomy & histology , Perches/anatomy & histology , Conservation of Natural Resources , Discriminant Analysis , Genotype , Multivariate Analysis , Nigeria , Principal Component Analysis , Perciformes/anatomy & histology , Perciformes/classification , Species SpecificityABSTRACT
Estimaram-se as correlações genéticas entre os escores visuais e as características reprodutivas, utilizando a estatística bayesiana sob modelo animal linear-limiar, em bovinos da raça Nelore. Foram estudadas características categóricas morfológicas, avaliadas visualmente aos oito, 15 e 22 meses de idade; e características contínuas de perímetro escrotal padronizado aos 365 e 450 dias de idade, além da idade ao primeiro parto. As estimativas de correlações genéticas foram de sentido favorável à seleção, apresentando magnitudes moderadas, sugerindo que a seleção de animais para um biótipo desejável pode levar a animais com maior fertilidade e precocidade sexual. As estimativas de correlação genética para o perímetro escrotal padronizado aos 450 dias e a idade ao primeiro parto com as características morfológicas avaliadas aos 22 meses de idade foram maiores do que as obtidas entre as características de escores visuais avaliadas aos oito e 15 meses de idade. A utilização de escores visuais como critério de seleção trará progresso genético também para as características reprodutivas.
The genetic correlations between visual scores and reproductive traits, using the bayesian statistic under the linear-threshold animal model, in bovines of the Nelore breed were estimated. Categorical morphological traits were also evaluated at eight, 15, and 22 month-old, concerning musculature, physical structure, conformation and sacrum, the escrotal circumferences measured at the ages of 365 and 450-day-old, and the age at first calving. The estimates of genetic correlations were moderates, suggesting that the selection of animals with better morphological conformation may lead to animals more precocious and with greater fertility. The estimates of genetic correlation concerning the escrotal circumference at 450 day-old and the age at first calving with the evaluated visual scores at 22 month-old were higher than the ones obtained between visual scores at eight and 15 month-old. The use of these visual scores as a criterion of selection may also bring genetic progress to the reproductive traits.
ABSTRACT
The aim of this study was to estimate the components of variance and genetic parameters for the visual scores which constitute the Morphological Evaluation System (MES), such as body structure (S), precocity (P) and musculature (M) in Nellore beef-cattle at the weaning and yearling stages, by using threshold Bayesian models. The information used for this was gleaned from visual scores of 5,407 animals evaluated at the weaning and 2,649 at the yearling stages. The genetic parameters for visual score traits were estimated through two-trait analysis, using the threshold animal model, with Bayesian statistics methodology and MTGSAM (Multiple Trait Gibbs Sampler for Animal Models) threshold software. Heritability estimates for S, P and M were 0.68, 0.65 and 0.62 (at weaning) and 0.44, 0.38 and 0.32 (at the yearling stage), respectively. Heritability estimates for S, P and M were found to be high, and so it is expected that these traits should respond favorably to direct selection. The visual scores evaluated at the weaning and yearling stages might be used in the composition of new selection indexes, as they presented sufficient genetic variability to promote genetic progress in such morphological traits.
ABSTRACT
Dieciséis (16) características de conformación de la raza Carora, fueron estudiadas en 3867 vacas. Los parámetros genéticos de las mismas se analizaron usando el modelo animal para características múltiples. Los efectos fijos considerados fueron: interacción rebaño-año, mes de evaluación, edad, estado de la lactancia y el clasificador del rebaño. Los parámetros genéticos se obtuvieron del REML para estimar los componentes de la (co)variancia. Las heredabilidades más altas se obtuvieron en la alzada (0,47) y profundidad corporal (0,27), mientras que el valor más bajo fue observado para el ángulo de la pezuña (0,03). Las características de la ubre mostraron bajo índice de herencia, estimándose un rango que iba de 0,06 para la inserción de la ubre trasera, a 0,13 para el nivel del piso de la ubre. Las correlaciones genéticas entre la alzada, profundidad corporal y ancho de la grupa fueron altas, con un rango de 0,76 a 0,86. Estimaciones altas se encontraron en la separación de pezones (0,16) y largo del pezón (0,26). La inserción delantera de la ubre fue positivamente asociada con la inserción de la ubre trasera (0,46), profundidad corporal (0,53), separación de pezones (0,17) y largo de pezones. (0,18), mientras correlación negativa se observó en el nivel del piso la ubre. Otras estimaciones negativas de correlación genética, se encontraron entre el nivel de grupa (-0,45), en las patas traseras vistas de atrás (-0,50), el nivel del piso de la ubre (-0,68) y la angulosidad. A su vez, la angulosidad fue positivamente asociada a la inserción trasera de ubre (0,62). Pequeñas correlaciones fueron estimadas entre el ángulo de la pezuña y la mayoría de las características evaluadas. La correlación genética negativa entre el desarrollo corporal y las características de la ubre, sugirieron que la selección por incremento de tamaño corporal no mejora la conformación de la ubre. Por lo tanto la selección debería estar orientada hacia animales de talla ...
Sixteen (16) morphological traits from 3867 Carora cows in Venezuela were studied. Genetic parameters were analyzed using a multiple trait animal model. Fixed effects of herd- year of evaluation interaction, month evaluation, age, stage of lactation classifier, within herd were considered, genetic parameters were obtained from REML estimates of covariance components. The highest heritability was found for stature (0.47) and for body depth (0.27), whereas the lowest values were found for foot angle (0.03). Udder traits showed low heritability estimates ranging from 0.06 for rear with to 0.13 for de udder balance. Higher estimations were found for tea placement side (0.16) and teat length (0.26). Genetic correlations among stature, body depth, strength and rump width were high and ranged from 0.76 to 0.86. Fore udder attachment was positively associated with rear udder height (0.46), udder depth (0.53), teat placement (0.17) and length (0.18) while a negative correlations with udder balance (-.028). Negative estimates genetic correlations were found between rump angle (-0.45), rear-legs rear view (-0.50), udder balance (-0.68), udder support (-0.32) y la angularity. Angularity was positively associated with rear udder height 0.62. Small correlations were estimated between foot angle and most traits. Negative genetic correlations between body development and udder traits suggested that selection to increase body size could not improve the udder conformation.. Selection should be oriented towards animals of medium size dairy characteristics.