Genetic parameters and mapping quantitative trait loci associated with tibia traits in broilers.

Abstract: Selection among broilers for performance traits is resulting in locomotion problems and bone disorders, once skeletal structure is not strong enough to support body weight in broilers with high growth rates. In this study, genetic parameters were estimated for body weight at 42 days of age (BW42), and tibia traits (length, width, and weight) in a population of broiler chickens. Quantitative trait loci (QTL) were identified for tibia traits to expand our knowledge of the genetic architecture of the broiler population. Genetic correlations ranged from 0.56 +/- 0.18 (between tibia length and BW42) to 0.89 +/- 0.06 (between tibia width and weight), suggesting that these traits are either controlled by pleiotropic genes or by genes that are in linkage disequilibrium. For QTL mapping, the genome was scanned with 127 microsatellites, representing a coverage of 2630 cM. Eight QTL were mapped on Gallus gallus chromosomes (GGA): GGA1, GGA4, GGA6, GGA13, and GGA24. The QTL regions for tibia length and weight were mapped on GGA1, between LEI0079 and MCW145 markers. The gene DACH1 is located in this region; this gene acts to form the apical ectodermal ridge, responsible for limb development. Body weight at 42 days of age was included in the model as a covariate for selection effect of bone traits. Two QTL were found for tibia weight on GGA2 and GGA4, and one for tibia width on GGA3. Information originating from these QTL will assist in the search for candidate genes for these bone traits in future studies.

Cooking time of common bean: genetic parameters and selection of elite lines.

The objectives of this study were to investigate the genetic variability and select elite lines for CT, since these lines aggregate essential agronomic traits.

Estimates of genetic parameters using RELM/BLUP for intrapopulational genetic breeding of Platonia insignis Mart.

The aim of this study was to estimate genetic parameters to support the selection of bacuri progenies for a first cycle of recurrent selection, using the REML/BLUP (restricted maximum likelihood/best linear unbiased prediction) procedure to estimate the variance components and genotypic values. Were evaluated twelve variables in a total of 210 fruits from 39 different seed trees, from a field trial with an experimental design of incomplete blocks with clonal replies among subplots. The three variables related with the fruit development (weight, diameter, length) showed strong correlation, and where fruit length showed higher heritability and potential to be used for indirect selection. Among the 39 progenies evaluated in this study, five present potential to compose the next cycle of recurrent selection, due they hold good selection differential either to agrotechnological variables as to development of bacuri fruit.

Bayesian estimates of genetic parameters for reproductive traits in Nellore cows raised on pasture in tropical regions.

2016

Genetic parameters for carcass traits and body weight using a Bayesian approach in the Canchim cattle.

Correlation between genetic parameters and factors such as backfat thickness (BFT), rib eye area (REA), and body weight (BW) were estimated for Canchim beef cattle raised in natural pastures of Brazil. Data from 1648 animals were analyzed using multi-trait (BFT, REA, and BW) animal models by the Bayesian approach. This model included the effects of contemporary group, age, and individual heterozygosity as covariates. In addition, direct additive genetic and random residual effects were also analyzed. Heritability estimated for BFT (0.16), REA (0.50), and BW (0.44) indicated their potential for genetic improvements and response to selection processes. Furthermore, genetic correlations between BW and the remaining traits were high (P > 0.50), suggesting that selection for BW could improve REA and BFT. On the other hand, genetic correlation between BFT and REA was low (P = 0.39 ± 0.17), and included considerable variations, suggesting that these traits can be jointly included as selection criteria without influencing each other. We found that REA and BFT responded to the selection processes, as measured by ultrasound. Therefore, selection for yearling weight results in changes in REA and BFT.

Variability and genetic parameters of chlorophyll content in forage peanut genotypes using the SPAD index.

This study aimed to verify the existence of variability and to estimate genetic parameters for chlorophyll content in forage peanut genotypes.

Different strategies to estimate genetic parameters for the rank of Santa Ines sheep in agricultural-shows.

2016

Variação genética para caracteres silviculturais em três espécies arbóreas da região do bolsão sul-mato-grossense.

O objetivo do presente estudo foi avaliar a variação genética e a seleção das melhores progênies de Myracrodruon urundeuva, Astronium fraxinifolium e Terminalia argentea, quanto aos caracteres de crescimento, em Selvíria, Mato Grosso do Sul. O teste de progênie foi instalado utilizando o delineamento de blocos ao acaso com 28 tratamentos, quatro repetições e dez plantas por parcela em linhas simples, no espaçamento 1,5 x 3,0 m. Aos 14 anos de idade, as progênies foram avaliadas quantos aos caracteres: altura (ALT); diâmetro a altura do peito (DAP); diâmetro médio da copa (DMC); forma do tronco (FT, escala de notas, variando de 1 a 5) e sobrevivência (SOB). Foram encontradas altas herdabilidades entre médias de progênies para os caracteres DAP (0,67), DMC (0,57) e forma do tronco (0,83), respectivamente. O ganho predito para DAP indica que a seleção baseada em informações, tanto de progênies, quanto de indivíduos dentro de progênies foram substanciais, o que denota uma boa perspectiva de exploração da variabilidade genética ao longo de um programa de melhoramento genético para as espécies estudadas, assim como o estabelecimento de estratégias para futura formação de um pomar de sementes.

Variabilidade genética e correlações entre caracteres de feijão-caupi.

2015

Bunch yield of interspecific hybrids of American oil palm with oil palm in the juvenile phase.

To identify superior genotypes, 42 progenies of interspecific hybrids between American oil palm and oil palm were evaluated in an area with incidence of bud rot. The following variables were assessed: total bunch yield (TBY), number of bunches (NB) and mean bunch weight (MBW) from the third to the sixth year of cultivation and estimates of genetic parameters obtained by REML/BLUP procedures.

Heritability and variability of bromatological traits evaluated in Panicum maximum hybrids in the Western Amazon.

The knowledge of the genetic parameters of bromatological traits in forages is essential to support the selection of genotypes that will be released as new cultivars. The objectives of this study were to estimate the heritability coefficients and verify the existence of genetic variability of bromatological traits in Panicum maximum hybrids, evaluated in the Western Amazon in different harvests over the year.