Heritability and genetics correlations for body weight in escargots

The objective of this study was to estimate genetic parameters for body weight at 60 (P60), 90 (P90), and 120 (P120) days of age in escargotsof the subspecies Cornu aspersum maximum, evaluating the influence of fixed and covariable effects on these traits. The data used were collected from escargotskept in a total confinement system. The significant fixed effects and covariates for these traits were tested in a general linear model by the F-test, considering a level of significance of 5%. Both the fixed effects of box and birth year and the quadratic effect of age of weighing as a covariate were significant (p < 0.05) for P60, P90, and P120. The Restricted Maximum Likelihood (REML) methodology was used to estimate (co)variance components and genetic parameters. High heritability for P60, P90, and P120 (0.38, 0.55 and 0.78, respectively) and high genetic correlations (0.58 to 0.77) among the traits were observed. The genetic parameterscan be used as a basis for studies and practical applications to increase zootechnical indexes in this population.(AU)

Genetic parameters and association between longevity and milk production in buffaloes using the ssGBLUP method

The objectives of this work were to estimate the genetic parameters for the traits longevity (LG) and accumulated milk yield at 305 days (MY305) using a bitrait animal model and the single-step GBLUP method and estimate the genetic gain for LG through direct and indirect selection for MY305. We used 4,057 records of first lactations of Murrah dairy buffaloes, collected between 1987 and 2020, belonging to six Brazilian herds located in the states Ceará, Rio Grande do Norte, and São Paulo and 960 animals genotyped using the 90K Axiom Buffalo Genotyping (Thermo Fisher Scientific, Santa Clara, CA) to estimate the genetic parameters. The heritability estimate was 0.25 for MY305 and 0.13 for LG. The genetic gain for LG was 0.13 months under direct selection, and 0.14 months under indirect selection, which results in a relative selection efficiency of 11% under selection for MY305 compared with the direct selection. The genetic correlation between the two traits was 0.77, indicating that animals with genetic potential for high MY305 tend to live longer. The genetic trends for MY305 and LG were 0.22 kg/year and 5.20 days/year, respectively, indicating a positive response, which reaffirms its relationship with the high genetic correlation between the two traits.(AU)

Morpho-agronomic and leaf anatomical traits in Coffeacanephora genotypes / Caracteres morfoagronômicos e anatômicos foliares em genótipos de Coffea canephora

ABSTRACT: Genetic variability is the basis for coffee genetic breeding. This study evaluated the potential of leaf anatomy and morpho-agronomic traits in studies of genetic variability in C. canephoracultivars. Ten genotypes were distributed in randomized block designs with three replicates. Significant differences among genotypes were detected by F-test (P < 0.05) for 13 of 15 evaluated traits. These results evidenced the heterogeneity of the studied cultivars, which is essential in composition of genetic basis in breeding programs. The Scott-Knott test detected variability among genotypes, grouped into up to four mean groups. Leaf anatomy traits presented the largest variations. Five out of seven leaf anatomy traits presented heritability higher than 80%, with emphasis on stomatal density (95.69%) and stomatal pore length (92.72%). Positive correlations were observed among morpho-agronomic and anatomic traits. Cluster analysis used the Mahalanobis general distance (D2) as a measure of genetic dissimilarity and divided the genotypes into two distinct groups. The inclusion of leaf anatomic traits to characterize C. canephoragenotypes may assist plant breeders with better genetic discrimination and with greater security in plant selection when composing cultivars.

RESUMO: A variabilidade genética é a base para o progresso genético em café. Este estudo teve como objetivo, avaliar o potencial de caracteres morfoagronômicos e anatômicos foliares em estudos de variabilidade genética entre cultivares de Coffea canephora. Dez genótipos foram distribuídos em um experimento seguindo delineamento em blocos ao acaso com três repetições. Foram detectadas diferenças significativas entre os genótipos pelo teste F (P < 0,05) para 13 dos 15 caracteres avaliados. Esses resultados evidenciaram a heterogeneidade entre as cultivares estudadas, o que é essencial para a composição da base genética e avanço dos programas de melhoramento. O teste de Scott e Knott detectou as diferenças entre os genótipos, separando-os em quatro grupos. Os caracteres anatômicos foliares apresentaram as maiores variações. Cinco, dentre os sete caracteres anatômicos foliares, apresentaram estimativas de herdabilidade superiores a 80% com destaque para a densidade estomática (95,69%) e comprimento do poro estomático (92,72%). Correlações positivas foram observadas entre caracteres morfoagronômicos e anatômicos foliares. A análise de agrupamento, considerando a distância de Mahalanobis como medida de dissimilaridade (D²), apontou a distinção de dois grupos de genótipos. A inclusão de caracteres anatômicos foliares na caracterização de genótipos de C. canephora pode auxiliar os melhoristas de plantas na melhor discriminação entre genótipos e maior segurança na seleção de clones para geração de novas cultivares.

Genetic correlation between feed efficiency and carcass traits in Nellore cattle in Brazil / Correlação genética entre características de eficiência alimentar e de carcaça em bovinos da raça Nelore no Brasi

The aim was to estimate the genetic correlations between residual feed intake (RFI) and dry matter intake (DMI) with carcass finish (CF), rib eye area (REA), and marbling (MAR) of Nellore cattle. Data from 7,808 animals were considered. In addition, data from 2,261 females included in the complete database were also considered. Estimates of variance and covariance components, as well as heritabilities and genetic correlations were obtained by means of two-character analysis under animal model. Heritability estimates were found to be moderate for the RFI (0.22) and DMI (0.29) traits. It was observed that genetic correlation was close to zero for all traits, except between RFI and REA (-0.11). However, considering the female population, there was an increase in the estimated genetic correlation between RFI and DMI, although still a favorable genetic association of low magnitude (-0.30). There was also an increase in the genetic association of REA with RFI (-0.21). It can be concluded that the direct selection for RFI and DMI will not influence the CF, MAR, or REA of Nellore cattle. However, this selection may generate some favorable responses in MAR and REA in Nellore females.

Objetivou-se estimar as correlações genéticas entre consumo alimentar residual (CAR) e ingestão de matéria seca com acabamento de carcaça (ACAB), área de olho de lombo (AOL) e marmoreio (MAR) para bovinos da raça Nelore. Foram consideradas informações de 7.808 animais. Além disso foram consideradas informações de 2.261 animais fêmeas que compunham o banco de dados completo. As estimativas dos componentes de variâncias e covariâncias, bem como das herdabilidades e correlações genéticas foram obtidas por meio de análises bicaracterísticas sob modelo animal. Verificou-se que as estimativas de herdabilidade foram moderadas para as características de CAR (0,22) e IMS (0,29). Observou-se que as estimativas de correlação genética foram próximos a zero para todas as Características, exceto entre CAR e AOL (-0,11). No entanto, considerando a população de fêmeas, houve um aumento na estimativa de correlação genética com CAR e IMS, apesar de ainda ser uma associação genética favorável de baixa magnitude (-0,30). Também houve um aumento na associação genética da AOL com o CAR (-0,21). Conclui-se, assim, que a seleção direta para o CAR e IMS não influenciará no ACAB, MAR e AOL de bovinos da raça Nelore. No entanto, essa seleção poderá gerar alguma resposta favorável em MAR e AOL em fêmeas Nelore.

Updating knowledge in estimating the genetics parameters: Multi-trait and Multi-Environment Bayesian analysis in rice

Among the multi-trait models selected to study several traits and environments jointly, the Bayesian framework has been a preferred tool when constructing a more complex and biologically realistic model. In most cases, non-informative prior distributions are adopted in studies using the Bayesian approach. However, the Bayesian approach presents more accurate estimates when informative prior distributions are used. The present study was developed to evaluate the efficiency and applicability of multi-trait multi-environment (MTME) models within a Bayesian framework utilizing a strategy for eliciting informative prior distribution using previous data on rice. The study involved data pertaining to rice (Oryza sativa L.) genotypes in three environments and five crop seasons (2010/2011 until 2014/2015) for the following traits: grain yield (GY), flowering in days (FLOR) and plant height (PH). Variance components, genetic and non-genetic parameters were estimated using the Bayesian method. In general, the informative prior distribution in Bayesian MTME models provided higher estimates of individual narrow-sense heritability and variance components, as well as minor lengths for the highest probability density interval (HPD), compared to their respective non-informative prior distribution analyses. More informative prior distributions make it possible to detect genetic correlations between traits, which cannot be achieved with non-informative prior distributions. Therefore, this mechanism presented to update knowledge for an elicitation of an informative prior distribution can be efficiently applied in rice breeding programs.

Path analysis and near-infrared spectroscopy in canola crop / Análise de trilha e espectroscopia no infravermelho próximo na cultura da canola

ABSTRACT: This study measured the effect of the association between agronomic traits related to the yield of canola grains grown at different sowing dates through path analysis. Another objective was to obtain a method to predict the oil content in the grains, fitting a multivariate model through near-infrared (NIR) spectroscopy analysis. The experiment was conducted in the field using a randomized block design in plots subdivided by time, with four plots (sowing dates), six subplots (canola hybrids), and four replicates. In each hybrid, phenological observations were performed, and the grain yield was determined. The data were subjected to analysis of variance in the R environment using the F test at 5% probability. The oil content in the grains was determined by the traditional chemical method, and based on the NIR spectral signature of the grain samples, partial least squares regression (PLS-R) was established to estimate the oil content in the canola grains. The sowing dates influenced the production components and oil content of the grains of all hybrids. The trait number of grains in five plants (0.6857) and their height (0.4943) had greater estimates of positive correlations with grain yield, as well as higher values of positive direct effects on yield (0.2494 and 0.1595, respectively). The NIR technique combined with PLS-R was able to predict the oil content in the grains, resulting in good predictive models (R2 of 0.86 and root mean square error (RMSE) of 1.56 in external validation).

RESUMO: Objetivou-se mensurar o efeito da associação entre caracteres agronômicos relacionados à produtividade de grãos de canola cultivada em diferentes épocas de semeadura, através da análise de trilha. Assim como também objetivou-se obter um método para predizer o teor de óleo nos grãos, ajustando um modelo multivariado através da análise por espectroscopia na região do infravermelho próximo. O experimento foi conduzido em campo, utilizando-se o delineamento de blocos ao acaso, em parcelas subdivididas no tempo, sendo quatro parcelas (épocas de semeadura) e seis subparcelas (híbridos de canola), com quatro repetições. Em cada híbrido foram realizadas observações fenológicas e determinada a produtividade de grãos. Os dados foram submetidos à análise de variância em ambiente R pelo teste F, a cinco de probabilidade. O teor de óleo nos grãos foi determinado pelo método químico tradicional, e com base na assinatura espectral no infravermelho próximo de amostras dos grãos foi estabelecida regressão dos mínimos quadrados parciais (PLS-R) para estimar o teor de óleo nos grãos de canola. As épocas de semeadura influenciaram os componentes de produção e o teor de óleo dos grãos de todos híbridos. Os caracteres número de grãos em cinco plantas (0,6857) e altura (0,4943) apresentaram maiores estimativas de correlação positiva com a produtividade de grãos, assim como os maiores valores de efeito direto positivo sobre a produtividade, 0,2494 e 0,1595 respectivamente. Entretanto, o ciclo total (-0,7848), juntamente com dias em florescimento (-0,4520) apresentou correlação significativa negativa com a produtividade. A técnica NIR associada à PLS-R foi capaz de predizer o teor de óleo nos grãos, resultando em bons modelos preditivos (R2 de 0,86 e RMSE de 1,56 na validação externa) que podem ser usados com sucesso na análise da qualidade das amostras após colheita e nos programas de melhoramento genético.

Characterization of yellow pitahaya (Selenicereus megalanthus Haw) genotypes under two productive systems in Colombia / Caracterização de genótipos de pitaia amarela (Selenicereus megalanthus Haw) a partir de dois sistemas produtivos na Colômbia

Selenicereus megalanthus Haw. It is an exotic fruit tree, with productive and nutritional potential. In Colombia, there is a great phenotypic and genotypic diversity, but its genetic studies are scarce. The objective was to characterize morphologically 15 selected yellow pitahaya genotypes, under two productive systems in the open field and under cover, in the municipalities of Miraflores and Zetaquira, in Boyacá, Colombia. Quantitative characters were evaluated: plant height (PH), number of vegetative sprouts (NVS), sub-sprouts (SS), longest sprouts length (LSL), distance between areoles (DBA), width of the ribs in the apical region (WRA), width of the ribs in the middle region (WRM), width of the ribs in the basal region (WRB), height of undulations between successive areoles in a rib (HUA), number of spines per areole (NSA) and longest spine length (LSP). The results showed under the two productive systems and the evaluated localities that the variables with the highest coefficient of variation (greater than 90%) were the number of sub-sprouts, height of the undulations between successive areoles (HUA) and the longest spine length (LSP). High positive correlations were obtained between the distances areoles, the width of the ribs and the length of the spines (r>0.7). The conglomerate showed that the characteristics that define the groupings are height of the plant, the texture of the cladodes, the width of the ribs and the height of the undulations. Characters associated with the shoots and cladodes were identified, which directly influence the vegetative propagation and therefore the yield of the yellow pitahaya.

Selenicereus megalanthus Haw é uma fruteira exótica, com potencial produtivo e nutricional. Na Colômbia existe uma grande diversidade fenotípica e genotípica, mas seus estudos genéticos são escassos. O objetivo deste trabalho foi caracterizar morfologicamente 15 genótipos selecionados de pitaya amarela, a partir de dois sistemas produtivos em campo aberto e sob cobertura, nos municípios de Miraflores e Zetaquira, em Boyacá, Colômbia. Foram avaliados os caracteres quantitativos: altura da planta (PH), número de brotos vegetativos (NVS), sub-brotos (SS), maior comprimento dos brotos (LSL), distância entre aréolas (DBA), largura das nervuras na região apical (WRA), largura das costelas na região média (WRM), largura das costelas na região basal (WRB), altura das ondulações entre aréolas sucessivas em uma costela (HUA), número de espinhos por aréola (NSA) e maior espinha comprimento (LSL). Os resultados mostraram nos dois sistemas produtivos e nas localidades avaliadas que as variáveis com maior coeficiente de variação (maior que 90%) foram o número de sub-brotos, altura das ondulações entre aréolas sucessivas (HUA) e o maior comprimento do espinho (LSL). Altas correlações positivas foram obtidas entre as distâncias entre as aréolas, a largura das costelas e o comprimento dos espinhos (r > 0.07). O conglomerado mostrou que as características que definem os agrupamentos são a altura da planta, a textura dos cladódios, a largura das nervuras e a altura das ondulações. Foram identificados caracteres associados à brotação e aos cladódios, que influenciam diretamente na propagação vegetativa e, consequentemente, na produção da pitaya-amarela.

Association of visual scores with reproductive traits in Nelore cattle using Bayesian Inference / Associação de escores visuais com características reprodutivas em bovinos Nelore utilizando Inferência Bayesiana

The use of morphological traits assessed using visual scores as indirect selection criteria in cattle has the advantage of evaluating young animals regarding potential productive and reproductive performance. This enables breeders to make earlier decisions compared to later measurements, such as scrotal circumference at 450 days (SC450) and stayability (STAY). The aim of this study was to estimate the genetic parameters for visual score traits and their associations with reproductive traits: scrotal circumference at 365 days of age (SC365), SC450, STAY, probability of precocious calving (PPC30) and age at first calving (AFC) in Nellore cattle. Visual score data from 4,175 Nellore cattle, with an average age of 22 months, and reproductive data from 3,075 cattle belonging to the HoRa Genetics Provada herd were used. The morphological traits were evaluated by the MERCOS methodology. The heritability estimates obtained ranged from 0.15 to 0.28 for visual scores and 0.10 to 0.54 for reproductive traits. Genetic correlations between visual scores and reproductive traits were generally low, except between: muscularity and PPC30; structure and STAY; racial and SC450; conformation and SC365, SC450, STAY, and AFC; navel and STAY and AFC; and sacrum and SC365, STAY, and AFC, which were moderate to high. The identification of animals with flat sacral bone (not protruding or sloping) can also be an efficient characteristic in the identification for early pregnancy, and together with the musculature score, they can be related to animals with lower age at the first calving.(AU)

A utilização de características morfológicas de bovinos, pelo uso de escores visuais como critério de seleção indireta tem como vantagem a avaliação em animais jovens quanto ao potencial desempenho produtivo e reprodutivo, antecipando a tomada de decisão em comparação a medidas tomadas de forma tardia, como perímetro escrotal aos 450 dias (PE450) e stayability (STAY). Objetivou-se estimar os parâmetros genéticos para características de escores visuais e a associação dessas com características reprodutivas, perímetro escrotal aos 365 (PE365) dias de idade, PE450, STAY, probabilidade de parto precoce (3P) e idade ao primeiro parto (IPP) em bovinos Nelore. Foram utilizadas informações de escores visuais e de reprodução de 4.175 e 3.075 bovinos, respectivamente, com idade média de 22 meses, pertencentes a fazenda HoRa Genética Provada. As características morfológicas foram avaliadas pela metodologia MERCOS. As estimativas de herdabilidade obtidas apresentam grande amplitude, variando de 0,15 a 0,28 para escores visuais e 0,10 a 0,54 para características reprodutivas. As correlações genéticas entre característica de escores visuais e reprodução foram, de maneira geral baixas (0.03-0.66), com exceção entre a musculosidade e 3P, estrutura e STAY, racial e PE450, conformação com PE365, PE450, STAY e IPP, ônfalo com STAY e IPP, e sacro com PE365, STAY e IPP, que foram moderadas a altas. A identificação de animais com melhor osso sacro (mesmo nível das ancas), ou seja, não saliente ou inclinado pode ser uma característica eficiente na identificação para prenhez precoce, e juntamente ao escore de musculatura poderão ser relacionados a animais com menor idade ao primeiro parto.(AU)

Path analysis and near-infrared spectroscopy in canola crop / Análise de trilha e espectroscopia no infravermelho próximo na cultura da canola

This study measured the effect of the association between agronomic traits related to the yield of canola grains grown at different sowing dates through path analysis. Another objective was to obtain a method to predict the oil content in the grains, fitting a multivariate model through near-infrared (NIR) spectroscopy analysis. The experiment was conducted in the field using a randomized block design in plots subdivided by time, with four plots (sowing dates), six subplots (canola hybrids), and four replicates. In each hybrid, phenological observations were performed, and the grain yield was determined. The data were subjected to analysis of variance in the R environment using the F test at 5% probability. The oil content in the grains was determined by the traditional chemical method, and based on the NIR spectral signature of the grain samples, partial least squares regression (PLS-R) was established to estimate the oil content in the canola grains. The sowing dates influenced the production components and oil content of the grains of all hybrids. The trait number of grains in five plants (0.6857) and their height (0.4943) had greater estimates of positive correlations with grain yield, as well as higher values of positive direct effects on yield (0.2494 and 0.1595, respectively). The NIR technique combined with PLS-R was able to predict the oil content in the grains, resulting in good predictive models (R2 of 0.86 and root mean square error (RMSE) of 1.56 in external validation).

Objetivou-se mensurar o efeito da associação entre caracteres agronômicos relacionados à produtividade de grãos de canola cultivada em diferentes épocas de semeadura, através da análise de trilha. Assim como também objetivou-se obter um método para predizer o teor de óleo nos grãos, ajustando um modelo multivariado através da análise por espectroscopia na região do infravermelho próximo. O experimento foi conduzido em campo, utilizando-se o delineamento de blocos ao acaso, em parcelas subdivididas no tempo, sendo quatro parcelas (épocas de semeadura) e seis subparcelas (híbridos de canola), com quatro repetições. Em cada híbrido foram realizadas observações fenológicas e determinada a produtividade de grãos. Os dados foram submetidos à análise de variância em ambiente R pelo teste F, a cinco de probabilidade. O teor de óleo nos grãos foi determinado pelo método químico tradicional, e com base na assinatura espectral no infravermelho próximo de amostras dos grãos foi estabelecida regressão dos mínimos quadrados parciais (PLS-R) para estimar o teor de óleo nos grãos de canola. As épocas de semeadura influenciaram os componentes de produção e o teor de óleo dos grãos de todos híbridos. Os caracteres número de grãos em cinco plantas (0,6857) e altura (0,4943) apresentaram maiores estimativas de correlação positiva com a produtividade de grãos, assim como os maiores valores de efeito direto positivo sobre a produtividade, 0,2494 e 0,1595 respectivamente. Entretanto, o ciclo total (-0,7848), juntamente com dias em florescimento (-0,4520) apresentou correlação significativa negativa com a produtividade. A técnica NIR associada à PLS-R foi capaz de predizer o teor de óleo nos grãos, resultando em bons modelos preditivos (R2 de 0,86 e RMSE de 1,56 na validação externa) que podem ser usados com sucesso na análise da qualidade das amostras após colheita e nos programas de melhoramento genético.

Genetic parameters for growth, reproductive, and carcass traits in Tabapuã cattle

We aimed to estimate genetic parameters for growth, reproductive, and carcass traits in Tabapuã cattle. Phenotypic data were collected between 1990 and 2019 in 1,218 farms, and the pedigree file had 340,868 animals. The traits evaluated were body weight at 120 (W120), 210 (W210), 365 (W365), and 550 (W550) days of age; age at first calving (AFC), scrotal circumference at 365 days of age (SC365), ribeye area (REA), backfat thickness (BF), and rump fat thickness (RF). The (co)variance components were estimated using the restricted maximum likelihood method, considering single and two-traits animal models. For all traits, the models considered fixed, direct additive genetic, and residual random effects. In addition, for W120 and W210, the maternal additive genetic and maternal permanent environmental effects were also included. Heritabilities for W120, W210, W365, W550, SC365, REA, BF, and RF were of moderate magnitude (0.15, 0.16, 0.23, 0.19, 0.22, 0.36, 0.31, and 0.27, respectively). Low heritability was observed for AFC (0.07). The genetic correlations between growth traits were higher than 0.90, while AFC and SC365 presented negative moderate correlation (−0.66). The REA showed low genetic correlations with BF (0.07) and RF (0.07), whereas BF and RF were highly correlated (0.77). Considering the heritability estimates, selection for AFC would result in limited genetic gain, while for the other traits, it would be satisfactory. Based on the high genetic correlations between growth traits, selection of Tabapuã animals can be performed at younger ages. Additionally, animals can be indirectly selected for AFC through SC365, and only one fat thickness trait may be used in the selection process considering the high genetic correlation and similar heritability values for BF and RF.(AU)

The impact of heterogeneity of variances on the genetic evaluation of performance traits in Nellore cattle

The objective was to evaluate the existence of heterogeneity of variances and its impact on the genetic evaluation of ponderal performance in sires of the Nellore breed. We used records of adjusted body weights at 210 (W210), 365 (W365), and 450 (W450) days of age. Both W365 and W450 were combined by principal component analyses using the first component (PC). Average daily gain (ADG) was obtained by difference between W450 and W210. The classes of standard deviations (SD) for W210, PC, and ADG were obtained by the standardization of means of herd-year means subclasses, with positive values composing the high SD and values equal and less than zero composing the SD. The model included the fixed effects of contemporary group and age at calving as a covariate, random genetic additive, and maternal genetic (except for PC) effects, and the permanent maternal environment. Variance components were obtained by Gibbs sampling. Posterior means of heritability in analyses without considering heterogeneity of variances ranged from 0.15±0.01 to 0.31±0.01. Posterior means of genetic correlations between the two classes of SD for W210, PC, and ADG were equal to 0.85±0.04, 0.83±0.03, and 0.71±0.08, respectively. Spearman correlation to breeding values of sires for ADG as the selection intensity increased in them, and the correlations between breeding values in general analyses were more correlated with those predicted in the high DP. Therefore, when there is a higher selection intensity on the sires only for the ADG criterion, there is a significant presence of the heterogeneity of variances and impact on the genetic evaluation of the sires. Thus, for ADG, the predictions of breeding values obtained by the genetic evaluation model in which the heterogeneity of variances are not considered are more weighted by the class of greater heterogeneity.(AU)

Genetic parameters and trends of growth traits in Nelore cattle raised in the Northern region of Brazil / Parâmetros genéticos e tendências de características de crescimento em gado Nelore criado na região norte do Brasil

The objective of this study was to estimate (co)variances and genetic parameters and to predict genetic trends for weight at 120 (W120), 210 (W210), 365 (W365), and 450 (W450) days of age in Nelore cattle raised in the northern region of Brazil. The database comprised records of 30,387 animals born between 2000 and 2013 in the Brazilian North. Estimates were calculated by the Restricted Maximum Likelihood (REML) method, in single- and multi-trait analyses in an animal model. Heritability as obtained using single- and multi-trait models for W120 (0.22 and 0.31), W210 (0.20 and 0.34), W365 (0.51 and 0.51), and W450 (0.49 and 0.51) indicated moderate to high magnitudes, with the possibility of genetic selection and incorporation into the herd. Genetic correlations between growth traits were favorable, ranging from 0.78 to 0.96. Genetic trends for W120 and W210 varied largely, from -0.31 to 4.68 and -0.53 to 7.62 kg/year, respectively. Smaller fluctuations were observed in genetic trends for W365 and W450, which ranged from -1.08 to 10.90 and -1.29 to 12.51 kg/year, respectively. Selection for W365 and W450 proved to be the criterion of choice for Nelore herds raised in the region; however, it may compromise adult performance because of higher costs and time for production. A thorough analysis of mattings is recommended to allow the selection of earlier-developing animals.(AU)

O presente trabalho foi delineado para estimar as (co) variâncias, parâmetros genéticos e de predizer as tendências genéticas para o peso aos 120 (W120), 210 (W210), 365 (W365) e 450 (W450) dias de idade de gado Nelore criado na região norte do Brasil. A base de dados foi constituituída por registro de 30387 animais, nascidos entre 2000 e 2013 no norte do Brasil. As estimativas foram calculadas pelo método de máxima restrição de probabilidade (REML) em um modelo animal com análises isoladas e multi variadas. A herdabilidade obtida para os modelos utilizados foi: W120 (0,22 e 0,31); W210 (0,20 e 0,34); W365 (0,51 e 0,51) e W450 (0,49 e 0,51), indicando moderada e alta magnitude com a possibilidade de seleção genética e incorporação no rebanho. As correlações genéticas entre grupos de tendências foram favoráveis variando de 0,78 a 0,96. As tendências genéticas para W120 e W210 apresentaram ampla variação de -0,31 a 4,68 e -0,53 a 7,62 kg/ano, respectivamente. Menores flutuações foram observadas nas tendências genéticas para W365 e W450, as quais variaram de -1,08 a 10,90 e -1,29 a12,51 kg/ano, respectivamente. Foi constatado que a seleção para W365 e W450 deve ser um critério de escolha para os rebanhos Nelore criados na região; contudo ela pode comprometer a performance dos adultos devido aos elevados custos e da duração da produção. Uma completa análise de cruzamentos é recomendada para possibilitar a seleção de animais jovens em desenvolvimento.(AU)

Mega-environment analysis of maize breeding data from Brazil

ABSTRACT: The development and recommendation of single cross maize hybrids (SH) to be used in extensive land areas (mega-environments), and in different crop seasons requires many experiments under numerous environmental conditions. The question we asked is if the data from these multi-environment experiments are sufficient to identify the best hybrid combinations. The aim of this study was to critically analyze the phenotype data of experiments of yield, established by a large seed producing company, under a high level of imbalance. Data from evaluation of 2770 SH were used from experiments conducted over four years, involving the first and second crop seasons, in 50 locations of different years and regions of Brazil. Different types of analysis were carried out and genetic and non-genetic components were estimated, with emphasis on the different interactions of the SH with the environments. Results showed that the coincidence of common hybrids in these experiments is normally small. The estimates of the correlations between of the hybrids coinciding in the environments two by two is of low magnitude. The hybrid × crop season interaction was always expressive; however, the interactions of hybrids and other environmental variables were also important. Under these conditions, alternatives were discussed for making with the information obtained from the experiments, can be more efficient on the process to obtain new hybrids by companies.

Genetic evaluation and selection of cocoa tree clones / Avaliação genética e seleção de clones de cacaueiro

The cultivation of cocoa is of great socio-economic importance worldwide. Cocoa beans are the essential raw material for chocolate production. The variability of cacao studied presents only a small fraction of the existing genetic diversity, mainly in the Amazon region. Furthermore, just a small part of this variability has been exploited in cocoa breeding. Thus, the present study processed the genetic evaluation and selection of cocoa clones, based on morpho-agronomical traits. For this, we evaluated 145 clones, during 37 harvests from, four consecutive years. The following traits were evaluated: total number of fruits collected (TNFC), total number of healthy fruits (TNHF), weight of wet seeds from healthy fruits (WWSHF), average weight of wet seeds per healthy fruit (AWWSHF), weight of dry seeds from healthy fruit (WDSHF), average weight of dry seeds per healthy fruit (AWDSHF), percentage of fruits with witches' broom disease (PFWB), percentage of fruits with borer (PFBR), percentage of fruits with germinated seeds (PFGS), number of branches with witches' broom disease (NBWB), and number of inflorescence with witches' broom disease (NIWB). Significant differences (P < 0.05) among the clones were observed for all traits, which reveal an expressive variability and possibility of gains with selection. The highest significant correlations (P < 0.05) occurred between traits TNFC and TNHF (0.94), TNHF and AWWSHF (0.86), and TNHF and AWDSHF (0.86). Based on the selection index, the clones POUND 12 and CAB 12, 228, 253, 257, 258, and 422 were the most suitable for selection.

O cultivo do cacau tem grande importância socioeconômica mundial. Os amêndoas de cacau são a matéria-prima essencial para a produção de chocolate. A variabilidade do cacaueiro avaliada representa apenas uma pequena fração da diversidade genética existente, principalmente na região amazônica. Além disso, apenas uma pequena parte dessa variabilidade foi explorada no melhoramento de cacau. Dessa forma, o presente estudo teve como objetivo realizar a avaliação genética e seleção de clones de cacau, com base em características morfo-agronômicas. Para isso, foram avaliados 145 clones, durante 37 colheitas, em quatro anos consecutivos. As seguintes características de frutos e sementes foram avaliadas: número total de frutos colhidos (NTFC), número total de frutos sadios (NTFS), peso de sementes úmidas dos frutos sadios (PSUFS), peso médio de sementes úmidas dos frutos sadios (PMSUFS), peso de sementes secas dos frutos sadios (PSSFS), peso médio de sementes secas dos frutos sadios (PMSSFS), porcentagem de frutos com vassoura-de-bruxa (PFVB), porcentagem de frutos com broca (PFBR), porcentagem de frutos com sementes germinadas (PFSG), número de ramos com vassoura-de-bruxa (NRVB) e número de almofadas florais com vassoura-de-bruxa (NAFVB). Diferenças significativas (P < 0,05) entre os clones foram observadas para todas as características, o que revela uma expressiva variabilidade e possibilidade de ganhos com a seleção. As maiores correlações significativas (P < 0,05) ocorreram entre os caracteres NTFC e NTFS (0,94), NTFS e PMSUFS (0,86) e, NTFS e PMSSFS (0,86). Com base no índice de seleção, os clones POUND 12 e CAB 12, 228, 253, 257, 258 e 422 foram considerados os mais adequados para a seleção.

Molecular characterization and association of lactoferrin gene to subclinical mastitis in goats (Capra hircus)

The study characterized the lactoferrin (Lf) mRNA gene in different goat breeds in the Philippines and determined its association with subclinical mastitis (SCM). The study involved collection of milk at second week of lactation (n=75) and blood samples (n=5) to obtain extracted RNA and using cDNA to amplify Lf gene through polymerase chain reaction. The nucleotide and amino acid sequences were determined and used as reference in the evaluation of phylogenetic relationship. Amplified products were utilized for RFLP analysis before determining the association of the gene with SCM. Results of the study demonstrated that Lf gene in goats registered a molecular weight of 2135. Nucleotide and amino acid sequence of Lf gene revealed high similarity (99%) in Saanen, Anglo-Nubian and Philippine native goats with that of Capra hircus (U53857) Lf gene submitted to GenBank. Phylogenetic studies showed that Lf gene of Anglo-Nubian, Saanen and Native goats clade together with Lf gene of C. hircus (U53857). Three genotypes in goats were documented using the restriction enzymes AluI and HaeIII. Based on the Statistical analysis, association (comp 5.65, p = 0.0308) has been established between the Lf genes of goats with genotype BB to SCM using HaeIII restriction enzyme.(AU)

Bovine landscape genetics in Brazil

The aim of this study was to explore spatial genetic structure patterns in cattle breeds adapted to local conditions in Brazil. We georeferenced 876 animals of ten breeds raised in Brazil kept in the Genebank of Brazilian Agricultural Research Corporation (Embrapa) by sample locations using the QGIS 2.4.0 software. The Mantel tests, spatial autocorrelation, and Monmonier tests were performed. The distances for spatial correlation tests ranged from 5 to 15 classes. The results indicated genetic discontinuities in cattle breeds from the Midwest, South, and Southeast of the country. Correlation between genetic and geographic distance was low, but significant. The Monmonier Maximum Distance Algorithm indicated an initial subdivision of Curraleiro and then Pantaneiro from the other breeds. In another subdivision, Criollo, Mocho Nacional, and Caracu were grouped. Genetic discontinuity was observed beyond 431 km, the minimum sampling distance between populations for conservation purposes.(AU)

Fit and genetic parameters of the growth curve of Polled Nellore cattle / Ajuste e parâmetros genéticos da curva de crescimento em bovinos da raça Nelore Mocho

This study was undertaken to compare different non-linear models for fitting growth curves of Polled Nellore animals as well as to estimate genetic parameters for the components of the growth curve. The study involved body weight-age data of 6,717 Polled Nellore cattle from birth to 650 days of age, which belonged to the Brazilian Association of Zebu Breeders (ABCZ), corresponding to the period from 1980 to 2011. Four non-linear models (Brody, Bertalanffy, Logistic, and Gompertz) were fitted and compared by the adjusted coefficient of determination (R2adj), mean absolute deviation of residuals (MAD), root mean square error (RMSE), Akaike information criterion (AIC), and Bayesian information criterion (BIC). To estimate the genetic parameters and genetic values of asymptotic weight (A), integration constant (B), and maturation rate (K), the Bayesian inference method was adopted. The Brody model showed the lowest values of MAD, RMSE, AIC, and BIC and the highest R2adj. Heritability estimates for parameters A, B, and K were 0.11, 0.16, and 0.30, respectively, whereas genetic correlations were 0.01 (A-B), -0.91 (A-K), and 0.24 (B-K). The Brody model provided the best fit. The K parameter shows enough genetic variability for selection in the herd. Heavier animals in adulthood tend to exhibit lower growth rates. Despite the low heritability estimate of parameter A, there were genetic gains, indicating that selection is being efficient on asymptotic weight.(AU)

O objetivo deste estudo foi comparar diferentes modelos não lineares para o ajuste das curvas de crescimento de animais da raça Nelore Mocho e estimar os parâmetros genéticos para os componentes da curva de crescimento. Foram utilizados dados de peso corporal-idade do nascimento aos 650 dias de idades de 6.717 bovinos da raça Nelore Mocho, pertencentes à Associação Brasileira de Criadores de Zebu (ABCZ), referentes ao período de 1980 e 2011. Quatro modelos não lineares (Brody, Bertalanffy, Logístico e Gompertz) foram ajustados e comparados pelo coeficiente de determinação ajustado (R2adj), desvio médio absoluto dos resíduos (DMA), raiz quadrada do quadrado médio do resíduo (RMSE), critério de informação de Akaike (AIC) e o critério de informação bayesiano (BIC). Para estimativas dos parâmetros genéticos e valores genéticos do peso assintótico (A), constante de integração (B) e taxa de maturação (K), utilizou-se o método de inferência Bayesiana. O modelo Brody apresentou os menores valores de DMA, RMSE, AIC e BIC e o maior R2adj. As estimativas de herdabilidade foram 0,11; 0,16 e 0,30 para os parâmetros A, B e K, respectivamente, enquanto as correlações genéticas foram de 0,01 (A-B), -0,91 (A-K) e 0,24 (B-K). Constatou-se que o modelo Brody forneceu o melhor ajuste. O parâmetro K apresenta variabilidade genética suficiente para seleção no rebanho. Animais com maior peso na idade adulta tendem a apresentar menores taxas de crescimento. Apesar da baixa estimativa de herdabilidade do parâmetro A, observou-se ganhos genéticos, indicando que a seleção está sendo eficiente sobre o peso assintótico.(AU)

Characterisation and pre-selection of Acca sellowiana genotypes by multivariate analysis / Caracterização e pré-seleção de genótipos de Acca sellowia por análise multivariada

Feijoa (Acca sellowiana) is a native Brazilian fruit with a peculiar flavour, a considerable amount of bioactive compounds and antioxidant activity. Even though this fruit tree is currently cultivated in several countries around the world, in Brazil, the process of domestication is underway, and the selection and breeding of new genotypes that are more productive and with better fruit quality is necessary. The objective of this work was to evaluate phenotypic diversity among and within progeny and to study the correlations among the quality variables of Feijoa fruit, seeking to select individuals with superior characteristics using principal component analysis. The parents who formed the progeny (families) were selected from a participatory breeding programme. We observed that individuals 47 and 93 had a combination of desirable fruit characteristics for selection, and individuals 15, 910, 98 and 410 should be selected for future crossings, as they had a high total fruit mass and soluble solid content or the highest percentage of pulp and rounded fruit shape. Larger fruit, in general, had a lower percentage of pulp. Principal component analysis is a viable tool in the pre-selection of new genotypes and potential progenitors for Feijoa breeding programmes.(AU)

Feijoa (Acca sellowiana) é uma fruteira nativa do Brasil com sabor peculiar, com considerável quantidade de compostos bioativos e atividade antioxidante. Mesmo sendo cultivada em diversos países, no Brasil, seu processo de domesticação está em curso e a seleção e o melhoramento para obtenção de novos genótipos, com maior produtividade e melhor qualidade de frutas, é necessário. O objetivo deste trabalho foi avaliar a diversidade fenotípica entre e dentro de progênies e estudar as correlações entre as variáveis de qualidade de frutos de Feijoa, buscando selecionar indivíduos com características superiores, usando análise de componentes principais. Os progenitores que formaram as populações (famílias) analisadas foram selecionados a partir de um programa de melhoramento participativo. Foi observado que os indivíduos 47 e 93 apresentaram uma combinação de características de frutos desejáveis para seleção, e os indivíduos 15, 910, 98 e 410 podem ser selecionados para futuros cruzamentos, pois possuem maior massa total de frutos e sólidos solúveis, ou maior porcentagem de rendimento de polpa e formato arredondado. Maior tamanho de frutos, em geral, tiveram uma menor percentagem de polpa. A análise de componentes principais é uma ferramenta viável para pré-seleção de genótipos e potencias progenitores em programas de melhoramento de Feijoa.(AU)

Genetic evaluation of oocyte and embryo production in dairy Gir cattle using repeatability and random regression models

The objective of this work is to estimate genetic parameters and breeding values to improve embryo and oocyte production, using repeatability and random regression models (RRM) for Gir dairy cattle. We used 11,398 records of ovum pick-up from 1,747 dairy Gir donors and evaluated sixteen different models: the traditional repeatability model and fifteen RRM, each of which considered a different combination of Legendre polynomial regressors to describe the additive genetic and permanent environment effects. The 4G1P model (four regressors for the genetic effect and one regressor for the permanent environment effect) is the most suitable model to analyze the number of viable and total oocytes, while the 3G1P is the best model to analyze the number of cleaved and viable embryos, according to the values of the Akaike information criterion (AIC) and the Bayesian information criterion (BIC). The heritability estimated with the RRM was higher than that estimated with the repeatability model. The high repeatability reported for oocyte and embryo count traits indicates that donors, which had high oocyte and embryo counts in the first ovum pick-up, should maintain this result in the next ovum pick-up. Genetic correlations between adjacent ages were high and positive, while genetic correlations between extreme ages were weak. We observed a reranking of the top sires and females (heifers and cows) over the period evaluated. The reliability of the estimated breeding values by RRM showed changes across age, and the expected genetic gains by RRM are larger. This shows that RRM is most suitable alternative for the evaluation and selection of oocyte and embryo count traits.(AU)

Mega-environment analysis of maize breeding data from Brazil

The development and recommendation of single cross maize hybrids (SH) to be used in extensive land areas (mega-environments), and in different crop seasons requires many experiments under numerous environmental conditions. The question we asked is if the data from these multi-environment experiments are sufficient to identify the best hybrid combinations. The aim of this study was to critically analyze the phenotype data of experiments of yield, established by a large seed producing company, under a high level of imbalance. Data from evaluation of 2770 SH were used from experiments conducted over four years, involving the first and second crop seasons, in 50 locations of different years and regions of Brazil. Different types of analysis were carried out and genetic and non-genetic components were estimated, with emphasis on the different interactions of the SH with the environments. Results showed that the coincidence of common hybrids in these experiments is normally small. The estimates of the correlations between of the hybrids coinciding in the environments two by two is of low magnitude. The hybrid × crop season interaction was always expressive; however, the interactions of hybrids and other environmental variables were also important. Under these conditions, alternatives were discussed for making with the information obtained from the experiments, can be more efficient on the process to obtain new hybrids by companies.