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)

Potential response from selection schemes based on progeny testing and genomic selection for the Chilean dairy cattle under pastoral systems: a deterministic simulation.

Recently, a selection index called Valor Económico Lechero (VEL) was developed for Chilean dairy cattle under pasture. However, a specific selection scheme has not yet been implemented. This study aimed to estimate genetic progress from selection on the VEL selection index based on selection schemes using progeny testing (PT) and genomic selection (GS). Under a PT-scheme, estimated genetic progress was 41.50, 3.44, and 2.33 kg/year for milk, fat, and protein yield, respectively. The realised genetic gain takes eight-year after the PT-scheme implementation, which may be a disincentive for implementing a PT-scheme, suggesting that importing frozen semen of proven bulls could be a preferred alternative. In this case, an option may be to conduct the genetic evaluation of those bulls using their progeny in Chile for the traits included in VEL selection index. In the case of implementing a specific selection scheme, compared to PT, a more profitable alternative might be the implementation of a GS-scheme, that would result in a faster genetic gain in the aggregate breeding value or merit for all the traits included in the selection objective (0.323-0.371 vs. 0.194 σg/year).

Genetic parameters of agronomic traits and yield components of soybean genotypes in the Colombian Altillanura / Parámetros genéticos de rasgos agronómicos y componentes de rendimiento de genotipos de soja en la Altillanura colombiana

ABSTRACT Soybean cultivation expansion in Colombia has generated the need to seek varieties with high genetic merit. A soybean genetic breeding program seeks to generate varieties with competitive and sustainable yields, and high-quality grain adapted to the conditions of the low tropics. The aim was to determine the genetic parameters and expected gains in quantitative traits of interest in a soybean breeding process using biometric tools. Sixty lines and four commercial varieties were evaluated in an 8x8 alpha lattice design (genotypes x blocks) planted in oxisols from the Altillanura region of Colombia. The estimation of the parameters was performed by applying mixed models with a random-effects adjustment through the REML method. Wide genetic variability was observed for all the evaluated traits, except for plant height. High heritability values were registered for the characters at flowering and maturity. Heritability was high for yield components such as the number of pods and the weight of 100 grains. Overall, the environmental effect was low, with values close to or higher than 1, except for embryonic abortions, number of empty pods, and grain yield. The genetic gain as a mean percentage was high for plant height, moderate for grain yield, and low for the rest of the characters. Moderate heritability and grain yield gain indicate an additive action of the genes ideal for recurrent selection. The most discriminating characters in the evaluated conditions were the grain yield, weight of 100 grains, and number of pods.

RESUMEN La expansión del cultivo de soya en Colombia genera la necesidad de buscar variedades con alto mérito genético y su mejoramiento, la generación de variedades con rendimientos competitivos y con alta calidad de grano, adaptadas a las condiciones del trópico bajo. El objetivo fue determinar, mediante herramientas biométricas, los parámetros genéticos y las ganancias esperadas, en caracteres cuantitativos de interés, para el proceso de mejora de soya. Se evaluaron 60 líneas y 4 variedades comerciales, en un diseño alfa látice 8x8, en oxisoles de la Altillanura. La estimación de los parámetros, se realizó mediante la aplicación de modelos mixtos, con ajuste de efectos aleatorios, por el método REML. Se observó amplia variabilidad genética para todos los rasgos evaluados, exceptuando la altura de planta. Se registraron valores altos de heredabilidad, para los caracteres de floración y madurez. En los componentes de rendimiento, la heredabilidad fue alta para número de vainas y peso de 100 granos. El efecto ambiental fue bajo, con valores cercanos o superiores a 1, con excepción de abortos embrionarios, número de vainas vanas y rendimiento de grano. La ganancia genética, como porcentaje de la media fue alta, para altura de planta; moderada, para rendimiento de grano y baja, para el resto de los caracteres. La heredabilidad y la ganancia moderadas de rendimiento de grano indican una acción aditiva de los genes, ideal para la selección recurrente. Los caracteres más discriminantes en las condiciones evaluadas fueron rendimiento de grano, peso de 100 granos y número de vainas.

Selection strategies for identifying fast cooking, mineral-biofortified bean cultivars with high agronomic performance

Simultaneous selection for various agronomic traits, cooking time and mineral concentration are major challenges for common-bean (Phaseolus vulgaris L.) breeding programs. The authors of this study proposed to analyze genetic gain estimates obtained by direct and indirect selection using selection indices and economic weights for 13 traits, and to determine the most efficient selection strategy for the simultaneous selection of fast cooking, mineral-biofortified common bean cultivars with high agronomic performance. For this purpose, three experiments were carried out in different growing seasons to evaluate 49 common bean cultivars of different grain types. Agronomic performance was evaluated based on six traits; cooking time was determined using a Mattson cooker; and the concentration of six minerals was analyzed in samples of raw grains. Significant genotype × environment interaction or genotype effects were observed for all traits, indicating the existence of genetic variability. Direct selection resulted in high genetic gain estimates for individual traits, but caused undesirable changes in one or more of the traits under selection. The classic, base, desired-gains and rank-sum selection indices tested with six economic weights do not provide genetic gain estimates favorable to the selection of all traits. The multiplicative index is the best selection strategy for use in the breeding program when aiming at the simultaneous selection of fast cooking, mineral-biofortified common bean cultivars with high agronomic performance.

Estimation of genetic parameters for body areas in Nile tilapia measured by digital image analysis.

Digital image analysis is a practical, non-invasive, and relatively low-cost tool that may assist in the evaluation of body traits in Nile tilapia, being particularly useful for assessing difficult-to-measure variables, such as body areas. In this study, we aimed to estimate variance components and genetic parameters for body areas of Nile tilapia obtained by digital images. The data set comprised body weight (BW) records of 1,917 pond-reared fish at 366 days of age. Of this total, 656 animals were photographed and subjected to image analysis of trunk area (TA), head area (HA), caudal fin area (CFA) and fillet area (FA). Heritabilities and genetic correlations were estimated through multiple-trait models based on Bayesian inference. Heritability estimates for BW, TA, HA, CFA and FA were 0.25, 0.23, 0.26, 0.21 and 0.25, respectively. Genetic correlations between the traits were high and positive, ranging from 0.70 to 0.98. We highlight the genetic correlation between BW and TA (rG  = 0.98) and FA (rG  = 0.97). In view of the observed results, it can be concluded that trunk and fillet areas obtained by digital image analysis can lead to indirect genetic gains in weight and other body areas. In addition, the areas studied have potential as a selection criterion and may assist in studies on changes in the body shape in Nile tilapia.

Combined selection for adaptability, genotypic stability and cowpea yield from mixed models / Seleção combinada para adaptabilidade, estabilidade genotípica e produtividade de feijão-caupi a partir de modelos mistos

The potential expression of crop productivity is a constant challenge for plant breeders in the face of oscillations in environmental variables, making selection difficult and increasing the operational and methodological costs in obtaining the ideal cultivar for a determined region. The objective of the research was to investigate the effects of genotype x environment interaction in the selection of cowpea lines with high grain yield, adaptability, and genotypic stability simultaneously, in environments of the Northwest region of Rio de Janeiro State, using mixed models (Maximum Restricted Likelihood - REML/Best Linear Unbiased Prediction - BLUP). 27 cowpea genotypes were evaluated in six environments by combining location (Cambuci-RJ and Bom Jesus do Itabapoana-RJ) and year (2016, 2017 and 2018). A randomized block design with four replications was performed. The genetic parameters were estimated via the REML/BLUP procedure, and the selection was based on the harmonic mean method of the relative performance of the genetic values (HMRPGV). A meaningful difference was observed for environment and genotype x environment interaction. The residual variance and the variance of the genotype x environment interaction formed the most significant fractions of the phenotypic variance. Lines 4 (Bico-de-ouro 1-5-24), 6 (Pingo-de-Ouro 1-5-4), 5 (Pingo-de-Ouro 1-5-26), and 9 (Pingo-de-Ouro 1-5-8), stood out as superior in terms of stability and adaptability and grain yield by HMRPGV. Commercial cultivars 13 (BRS-Tumucumaque) and 26 (BRS-Itaim) had high grain yield, adaptability, and specific stability in the evaluated edaphoclimatic conditions.(AU)

A expressão potencial da produtividade das culturas constitui um desafio constante aos criadores de plantas frente às oscilações das variáveis ambientais, dificultando a seleção e onerando os custos operacionais e metodológicos na obtenção da cultivar ideal para determinada região. O objetivo do trabalho foi investigar os efeitos da interação genótipos x ambientes na seleção de linhagens de feijão-caupi com alta produtividade de grãos, adaptabilidade e estabilidade genotípica simultaneamente, em ambientes da região Noroeste do estado do Rio de Janeiro, usando modelos mistos (Máximo Verosimilhança Restrita - REML/Melhor Predição Linear não Viesado - BLUP). Avaliou-se 27 genótipos de feijão-caupi em seis ambientes pela combinação de local (Cambuci-RJ e Bom Jesus do Itabapoana-RJ) e ano (2016, 2017 e 2018). Foi utilizado o delineamento em blocos casualizados com quatro repetições. Os parâmetros genéticos foram estimados via procedimento REML/BLUP, e a seleção baseou-se no método da média harmônica do desempenho relativo dos valores genéticos (HMRPGV). Observou-se diferença significativa para ambiente e interação genótipo x ambiente. A variância residual e a variância da interação genótipo x ambiente formaram as maiores frações da variância fenotípica. As linhagens 4 (Bico-de-ouro 1-5-24), 6 (Pingo-de-ouro 1-5-4), 5 (Pingo-de-ouro 1-5-26) e 9 (Pingo-de-ouro 1-5-8) foram classificadas como superiores quanto a estabilidade e adaptabilidade e rendimento de grãos pelo critério da HMRPGV. As cultivares comerciais 13 (BRS-Tumucumaque) e 26 (BRS-Itaim) reuniram elevada produtividade de grãos, adaptabilidade e estabilidade específica nas condições edafoclimáticas avaliadas.(AU)

Combined selection for adaptability, genotypic stability and cowpea yield from mixed models / Seleção combinada para adaptabilidade, estabilidade genotípica e produtividade de feijão-caupi a partir de modelos mistos

ABSTRACT: The potential expression of crop productivity is a constant challenge for plant breeders in the face of oscillations in environmental variables, making selection difficult and increasing the operational and methodological costs in obtaining the ideal cultivar for a determined region. The objective of the research was to investigate the effects of genotype x environment interaction in the selection of cowpea lines with high grain yield, adaptability, and genotypic stability simultaneously, in environments of the Northwest region of Rio de Janeiro State, using mixed models (Maximum Restricted Likelihood - REML/Best Linear Unbiased Prediction - BLUP). 27 cowpea genotypes were evaluated in six environments by combining location (Cambuci-RJ and Bom Jesus do Itabapoana-RJ) and year (2016, 2017 and 2018). A randomized block design with four replications was performed. The genetic parameters were estimated via the REML/BLUP procedure, and the selection was based on the harmonic mean method of the relative performance of the genetic values (HMRPGV). A meaningful difference was observed for environment and genotype x environment interaction. The residual variance and the variance of the genotype x environment interaction formed the most significant fractions of the phenotypic variance. Lines 4 (Bico-de-ouro 1-5-24), 6 (Pingo-de-Ouro 1-5-4), 5 (Pingo-de-Ouro 1-5-26), and 9 (Pingo-de-Ouro 1-5-8), stood out as superior in terms of stability and adaptability and grain yield by HMRPGV. Commercial cultivars 13 (BRS-Tumucumaque) and 26 (BRS-Itaim) had high grain yield, adaptability, and specific stability in the evaluated edaphoclimatic conditions.

RESUMO: A expressão potencial da produtividade das culturas constitui um desafio constante aos criadores de plantas frente às oscilações das variáveis ambientais, dificultando a seleção e onerando os custos operacionais e metodológicos na obtenção da cultivar ideal para determinada região. O objetivo do trabalho foi investigar os efeitos da interação genótipos x ambientes na seleção de linhagens de feijão-caupi com alta produtividade de grãos, adaptabilidade e estabilidade genotípica simultaneamente, em ambientes da região Noroeste do estado do Rio de Janeiro, usando modelos mistos (Máximo Verosimilhança Restrita - REML/Melhor Predição Linear não Viesado - BLUP). Avaliou-se 27 genótipos de feijão-caupi em seis ambientes pela combinação de local (Cambuci-RJ e Bom Jesus do Itabapoana-RJ) e ano (2016, 2017 e 2018). Foi utilizado o delineamento em blocos casualizados com quatro repetições. Os parâmetros genéticos foram estimados via procedimento REML/BLUP, e a seleção baseou-se no método da média harmônica do desempenho relativo dos valores genéticos (HMRPGV). Observou-se diferença significativa para ambiente e interação genótipo x ambiente. A variância residual e a variância da interação genótipo x ambiente formaram as maiores frações da variância fenotípica. As linhagens 4 (Bico-de-ouro 1-5-24), 6 (Pingo-de-ouro 1-5-4), 5 (Pingo-de-ouro 1-5-26) e 9 (Pingo-de-ouro 1-5-8) foram classificadas como superiores quanto a estabilidade e adaptabilidade e rendimento de grãos pelo critério da HMRPGV. As cultivares comerciais 13 (BRS-Tumucumaque) e 26 (BRS-Itaim) reuniram elevada produtividade de grãos, adaptabilidade e estabilidade específica nas condições edafoclimáticas avaliadas.

Combined selection for adaptability, genotypic stability and cowpea yield from mixed models / Seleção combinada para adaptabilidade, estabilidade genotípica e produtividade de feijão-caupi a partir de modelos mistos

The potential expression of crop productivity is a constant challenge for plant breeders in the face of oscillations in environmental variables, making selection difficult and increasing the operational and methodological costs in obtaining the ideal cultivar for a determined region. The objective of the research was to investigate the effects of genotype x environment interaction in the selection of cowpea lines with high grain yield, adaptability, and genotypic stability simultaneously, in environments of the Northwest region of Rio de Janeiro State, using mixed models (Maximum Restricted Likelihood - REML/Best Linear Unbiased Prediction - BLUP). 27 cowpea genotypes were evaluated in six environments by combining location (Cambuci-RJ and Bom Jesus do Itabapoana-RJ) and year (2016, 2017 and 2018). A randomized block design with four replications was performed. The genetic parameters were estimated via the REML/BLUP procedure, and the selection was based on the harmonic mean method of the relative performance of the genetic values (HMRPGV). A meaningful difference was observed for environment and genotype x environment interaction. The residual variance and the variance of the genotype x environment interaction formed the most significant fractions of the phenotypic variance. Lines 4 (Bico-de-ouro 1-5-24), 6 (Pingo-de-Ouro 1-5-4), 5 (Pingo-de-Ouro 1-5-26), and 9 (Pingo-de-Ouro 1-5-8), stood out as superior in terms of stability and adaptability and grain yield by HMRPGV. Commercial cultivars 13 (BRS-Tumucumaque) and 26 (BRS-Itaim) had high grain yield, adaptability, and specific stability in the evaluated edaphoclimatic conditions.

A expressão potencial da produtividade das culturas constitui um desafio constante aos criadores de plantas frente às oscilações das variáveis ambientais, dificultando a seleção e onerando os custos operacionais e metodológicos na obtenção da cultivar ideal para determinada região. O objetivo do trabalho foi investigar os efeitos da interação genótipos x ambientes na seleção de linhagens de feijão-caupi com alta produtividade de grãos, adaptabilidade e estabilidade genotípica simultaneamente, em ambientes da região Noroeste do estado do Rio de Janeiro, usando modelos mistos (Máximo Verosimilhança Restrita - REML/Melhor Predição Linear não Viesado - BLUP). Avaliou-se 27 genótipos de feijão-caupi em seis ambientes pela combinação de local (Cambuci-RJ e Bom Jesus do Itabapoana-RJ) e ano (2016, 2017 e 2018). Foi utilizado o delineamento em blocos casualizados com quatro repetições. Os parâmetros genéticos foram estimados via procedimento REML/BLUP, e a seleção baseou-se no método da média harmônica do desempenho relativo dos valores genéticos (HMRPGV). Observou-se diferença significativa para ambiente e interação genótipo x ambiente. A variância residual e a variância da interação genótipo x ambiente formaram as maiores frações da variância fenotípica. As linhagens 4 (Bico-de-ouro 1-5-24), 6 (Pingo-de-ouro 1-5-4), 5 (Pingo-de-ouro 1-5-26) e 9 (Pingo-de-ouro 1-5-8) foram classificadas como superiores quanto a estabilidade e adaptabilidade e rendimento de grãos pelo critério da HMRPGV. As cultivares comerciais 13 (BRS-Tumucumaque) e 26 (BRS-Itaim) reuniram elevada produtividade de grãos, adaptabilidade e estabilidade específica nas condições edafoclimáticas avaliadas.

Selection indexes for Nellore production system in the Brazilian Pantanal

The objective was to develop selection indexes for Nellore cattle raised in full-cycle production system in the Brazilian Pantanal. The resulting offspring are retained as replacements or sold at two years of age. Preliminary analyses explored effects of scale on economic values (EV). However, given the available data, these effects were very small. Presented herein are results from a simulated system consisting of 5,000 cows with all animals maintained on pasture as is typical in Pantanal. The EV were determined by approximating the partial derivatives of the profit function, changing one trait at a time, by one unit, while keeping the other traits constant. Traits in the breeding objective were mature cow weight, direct and maternal weaning weight, postweaning average daily gain, subcutaneous fat depth, longissimus muscle area, and stayability. Economic values were calculated on the basis of number of animals (per head), number of animal units, and arroba of carcasss weight. Regardless of the basis, maternal weaning weight and subcutaneous fat depth made negligible contributions to the breeding objective. Proportions of variation in the breeding objectives (per head, per animal unit, per arroba) explained by cow weight, direct weaning weight, postweaning average daily gain, stayability, and longissimus muscle area were: 13, 13, 17; 6, 1, 5; 3, 3, 4; 67, 67, 61; and 11, 17, 13, respectively. These indexes may aid Nellore breeders in their selection decisions, thus facilitating the genetic progress and increased productivity and profitability of Pantanal herds.

Estimation of genetic parameters and trends for morphometric traits in Brazilian Mangalarga Marchador horses

The objective of this work was to estimate genetic parameters and evaluate genetic trends over 26 years for morphometric traits in Mangalarga Marchador horses. Twelve morphometric traits were evaluated (withers and croup heights; length of head, body, shoulder, croup, neck, back, and loins; width of head and croup, and cannon bone and thorax perimeters). These traits were evaluated in 38,341 animals born between 1987 and 2012 and with a relationship matrix of 77,719 animals. Gibbs sampler was used to obtain samples of the posterior distributions of genetic parameters under animal models. Genetic trends were estimated by regression of estimated breeding values in function of birth year. The heritabilities of all traits were moderate to high and ranged from 0.27 to 0.48. However, the additive genetic coefficients of variation were low, ranging from 1.23 to 3.82%. The genetic trends of all the studied traits were significant, but of low magnitude. Negative genetic trend was observed for body length, while positive genetic trends were estimated for the other 11 traits. Although additive genetic differences accounted for a significant part of the phenotypic differences, genetic gains in the population were limited by low phenotypic variability. Therefore, it is necessary to develop data collection strategies to increase phenotypic and genetic variability in the population, such as the inclusion of animals that do not meet breed standard, but which have parents registered in the breeders' association, in the database.

Efficiency of a Constrained Linear Genomic Selection Index To Predict the Net Genetic Merit in Plants.

The constrained linear genomic selection index (CLGSI) is a linear combination of genomic estimated breeding values useful for predicting the net genetic merit, which in turn is a linear combination of true unobservable breeding values of the traits weighted by their respective economic values. The CLGSI is the most general genomic index and allows imposing constraints on the expected genetic gain per trait to make some traits change their mean values based on a predetermined level, while the rest of them remain without restrictions. In addition, it includes the unconstrained linear genomic index as a particular case. Using two real datasets and simulated data for seven selection cycles, we compared the theoretical results of the CLGSI with the theoretical results of the constrained linear phenotypic selection index (CLPSI). The criteria used to compare CLGSI vs. CLPSI efficiency were the estimated expected genetic gain per trait values, the selection response, and the interval between selection cycles. The results indicated that because the interval between selection cycles is shorter for the CLGSI than for the CLPSI, CLGSI is more efficient than CLPSI per unit of time, but its efficiency could be lower per selection cycle. Thus, CLGSI is a good option for performing genomic selection when there are genotyped candidates for selection.

New insights into genomic selection through population-based non-parametric prediction methods

Genome-wide selection (GWS) is based on a large number of markers widely distributed throughout the genome. Genome-wide selection provides for the estimation of the effect of each molecular marker on the phenotype, thereby allowing for the capture of all genes affecting the quantitative traits of interest. The main statistical tools applied to GWS are based on random regression or dimensionality reduction methods. In this study a new non-parametric method, called Delta-p was proposed, which was then compared to the Genomic Best Linear Unbiased Predictor (G-BLUP) method. Furthermore, a new selection index combining the genetic values obtained by the G-BLUP and Delta-p, named Delta-p/G-BLUP methods, was proposed. The efficiency of the proposed methods was evaluated through both simulation and real studies. The simulated data consisted of eight scenarios comprising a combination of two levels of heritability, two genetic architectures and two dominance status (absence and complete dominance). Each scenario was simulated ten times. All methods were applied to a real dataset of Asian rice (Oryza sativa) aiming to increase the efficiency of a current breeding program. The methods were compared as regards accuracy of prediction (simulation data) or predictive ability (real dataset), bias and recovery of the true genomic heritability. The results indicated that the proposed Delta-p/G-BLUP index outperformed the other methods in both prediction accuracy and predictive ability.(AU)

New insights into genomic selection through population-based non-parametric prediction methods

Genome-wide selection (GWS) is based on a large number of markers widely distributed throughout the genome. Genome-wide selection provides for the estimation of the effect of each molecular marker on the phenotype, thereby allowing for the capture of all genes affecting the quantitative traits of interest. The main statistical tools applied to GWS are based on random regression or dimensionality reduction methods. In this study a new non-parametric method, called Delta-p was proposed, which was then compared to the Genomic Best Linear Unbiased Predictor (G-BLUP) method. Furthermore, a new selection index combining the genetic values obtained by the G-BLUP and Delta-p, named Delta-p/G-BLUP methods, was proposed. The efficiency of the proposed methods was evaluated through both simulation and real studies. The simulated data consisted of eight scenarios comprising a combination of two levels of heritability, two genetic architectures and two dominance status (absence and complete dominance). Each scenario was simulated ten times. All methods were applied to a real dataset of Asian rice (Oryza sativa) aiming to increase the efficiency of a current breeding program. The methods were compared as regards accuracy of prediction (simulation data) or predictive ability (real dataset), bias and recovery of the true genomic heritability. The results indicated that the proposed Delta-p/G-BLUP index outperformed the other methods in both prediction accuracy and predictive ability.

Genetic parameters of growth, and resistance to the shoot borer, in young clones of the tree Cedrela odorata (Meliaceae)

Damage by Hypsipyla grandella Zeller restricts the success of plantations of Cedrela odorata. The most critical and vulnerable infection period by H. grandella is during the first three years. The aim was to estimate the expected genetic gain for the selection of clones of fast growth and resistant to the attack by this insect. A trial with 40 clones produced by grafting was planted in Veracruz, Mexico. Heritability, genetic correlations and genetic gain of clones were estimated with data at two years-old. The survival rate of the trial was of 97 % (466 living ramets in total), 2.84 m in total high and 2.32 cm of average normal diameter. Aditionally, 9.9 % of the ramets did not present attacks, indication of evasion, and 0.6 percent without response to attack. With response to attack 89.5 % of the ramets (several degrees of tolerance): 29 % with a single shoot, 14.2 % with several shoots and 46.3 % with a dominant shoot of several shoots formed. The clonal heritability of normal diameter, height, volume, stem taper index, number of attacks and response to the attack was H2c = 0.81, 0.80, 0.81, 0.61, 0.34, and 0.26. The genetic correlations between height, diameter and volume were ≥ 0.95, and the correlation of the volume with the incidence and the response to the attack was rg = -0.31 and rg = 0.62, that is a decrease in number of attacks and moderate increase in tolerance. With a selection intensity of 10 %, selecting the four clones with higher volume will produce a genetic gain of 82 % for volume, a decrease of 10.9 % of number of attacks and 6.3 % of better recovery from damage; this is more tolerance to the insect attack. The genetic gain justifies the use of the best clones in commercial plantations in Veracruz, Mexico.

El daño por Hypsipyla grandella limita el éxito de las plantaciones de Cedrela odorata. El periodo más crítico y vulnerable es durante los primeros tres años. El objetivo del estudio fue estimar la ganancia genética esperada en la selección de clones de mayor crecimiento y resistentes al ataque del insecto. Un ensayo de 40 clones producidos por injertos fue plantado en Veracruz, México. Con datos a la edad de dos años se estimaron: la heredabilidad, correlaciones genéticas y ganancia genética de los clones. El ensayo presentó una supervivencia del 97 % (466 rametos vivos en total), con 2.84 m de altura y 2.32 cm de diámetro normal promedio. El 9.9 % de los rametos no presentaron ataques, indicando evasión, y se estimó un 0.6 % sin respuesta al ataque. Con respuesta al ataque 89.5 % de los rametos (diferentes niveles de tolerancia): 29 % con un solo brote, 14.2 % con varios brotes, y 46.3 % con un brote dominante de varios brotes formados. La heredabilidad clonal del diámetro normal, altura, volumen, índice de conicidad, número de ataques y respuesta al ataque fue de H2 c = 0.81, 0.80, 0.81, 0.61, 0.34 y 0.26, respectivamente. Las correlaciones genéticas entre la altura, diámetro y volumen fueron ≥ 0.95, y del volumen con la incidencia y la respuesta al ataque de rg = -0.31 y rg = 0.62, es decir se presentó una disminución en el número de ataques y el aumento moderado en la tolerancia. Con una intensidad de selección del 10 %, seleccionando los cuatro clones de mayor volumen se obtuvo una ganancia genética de 82 % para el volumen, una disminución de 10.9 % de ataques y 6.3 % mejor recuperación del daño, esto es más tolerancia al ataque del insecto. La ganancia genética justifica la utilización de los mejores clones en plantaciones comerciales para Veracruz.

Optimizing Genomic Selection for a Sorghum Breeding Program in Haiti: A Simulation Study.

Young breeding programs in developing countries, like the Chibas sorghum breeding program in Haiti, face the challenge of increasing genetic gain with limited resources. Implementing genomic selection (GS) could increase genetic gain, but optimization of GS is needed to account for these programs' unique challenges and advantages. Here, we used simulations to identify conditions under which genomic-assisted recurrent selection (GARS) would be more effective than phenotypic recurrent selection (PRS) in small new breeding programs. We compared genetic gain, cost per unit gain, genetic variance, and prediction accuracy of GARS (two or three cycles per year) vs. PRS (one cycle per year) assuming various breeding population sizes and trait genetic architectures. For oligogenic architecture, the maximum relative genetic gain advantage of GARS over PRS was 12-88%, which was observed only during the first few cycles. For the polygenic architecture, GARS provided maximum relative genetic gain advantage of 26-165%, and was always superior to PRS. Average prediction accuracy declines substantially after several cycles of selection, suggesting the prediction models should be updated regularly. Updating prediction models every year increased the genetic gain by up to 33-39% compared to no-update scenarios. For small populations and oligogenic traits, cost per unit gain was lower in PRS than GARS. However, with larger populations and polygenic traits cost per unit gain was up to 67% lower in GARS than PRS. Collectively, the simulations suggest that GARS could increase the genetic gain in small young breeding programs by accelerating the breeding cycles and enabling evaluation of larger populations.

Combined index of genomic prediction methods applied to productivity / Índice combinado de métodos de predição genômica aplicado em características de produtividade em arroz

Rice cultivation has great national and global importance, being one of the most produced and consumed cereals in the world and the primary food for more than half of the worlds population. Because of its importance as food, developing efficient methods to select and predict genetically superior individuals in reference to plant traits is of extreme importance for breeding programs. The objective of this research was to evaluate and compare the efficiency of the Delta-p, G-BLUP (Genomic Best Linear Unbiased Predictor), BayesCpi, BLASSO (Bayesian Least Absolute Shrinkage and Selection Operator), Delta-p/G-BLUP index, Delta-p/BayesCpi index, and Delta-p/BLASSO index in the estimation of genomic values and the effects of single nucleotide polymorphisms on phenotypic data associated with rice traits. Use of molecular markers allowed high selective efficiency and increased genetic gain per unit time. The Delta-p method uses the concept of change in allelic frequency caused by selection and the theoretical concept of genetic gain. The Index is based on the principle of combined selection, using the information regarding the additive genomic values predicted via G-BLUP, BayesCpi, BLASSO, or Delta-p. These methods were applied and compared for genomic prediction using nine rice traits: flag leaf length, flag leaf width, panicles number per plant, primary panicle branch number, seed length, seed width, amylose content, protein content, and blast resistance. Delta-p/G-BLUP index had higher predictive abilities for the traits studied, except for amylose content trait in which the method with the highest predictive ability was BayesCpi, being approximately 3% greater than that of the Delta-p/G-BLUP index.(AU)

A cultura do arroz tem grande importância nacional e mundial por ser um dos cereais mais produzidos e consumidos no mundo, caracterizando-se como o principal alimento de mais da metade da população mundial. Em função de sua importância alimentar, desenvolver métodos eficientes que visam a predição e a seleção de indivíduos geneticamente superiores, quanto a características da planta, é de extrema importância para os programas de melhoramento. Diante disso, o objetivo deste trabalho foi avaliar e comparar a eficiência do método Delta-p, G-BLUP, BayesCpi, BLASSO e o índice Delta-p/G-BLUP, índice Delta-p/BayesCpi e índice Delta-p/BLASSO, na estimação de valores genômicos e dos efeitos de marcadores SNPs (Single Nucleotide Polymorphisms) em dados fenotípicos associados a características de arroz. A utilização de marcadores moleculares permite alta eficiência seletiva e o aumento do ganho genético por unidade de tempo. O método Delta-p utiliza o conceito de mudança na frequência alélica devido à seleção e o conceito teórico de ganho genético. O Índice é baseado no princípio da seleção combinada, utiliza conjuntamente as informações dos valores genômicos aditivos preditos via G-BLUP, BayesCpi ou BLASSO e via Delta-p. Estes métodos foram aplicados e comparados quanto à predição genômica utilizando nove características de arroz (Oryza sativa), sendo elas: comprimento da folha bandeira, largura da folha bandeira; número de panículas por planta; número de ramos da panícula primária; comprimento de semente; largura de semente; teor de amilose; teor de proteína; resistência a bruzone. O índice Delta-p/G-BLUP obteve maiores capacidades preditivas para as características estudadas, exceto para a característica Conteúdo de amilose, em que o método que obteve maior capacidade preditiva foi o BayesCpi, sendo aproximadamente 3% superior ao índice Delta-p/G-BLUP.(AU)

Combined index of genomic prediction methods applied to productivity / Índice combinado de métodos de predição genômica aplicado em características de produtividade em arroz

ABSTRACT: Rice cultivation has great national and global importance, being one of the most produced and consumed cereals in the world and the primary food for more than half of the world's population. Because of its importance as food, developing efficient methods to select and predict genetically superior individuals in reference to plant traits is of extreme importance for breeding programs. The objective of this research was to evaluate and compare the efficiency of the Delta-p, G-BLUP (Genomic Best Linear Unbiased Predictor), BayesCpi, BLASSO (Bayesian Least Absolute Shrinkage and Selection Operator), Delta-p/G-BLUP index, Delta-p/BayesCpi index, and Delta-p/BLASSO index in the estimation of genomic values and the effects of single nucleotide polymorphisms on phenotypic data associated with rice traits. Use of molecular markers allowed high selective efficiency and increased genetic gain per unit time. The Delta-p method uses the concept of change in allelic frequency caused by selection and the theoretical concept of genetic gain. The Index is based on the principle of combined selection, using the information regarding the additive genomic values predicted via G-BLUP, BayesCpi, BLASSO, or Delta-p. These methods were applied and compared for genomic prediction using nine rice traits: flag leaf length, flag leaf width, panicles number per plant, primary panicle branch number, seed length, seed width, amylose content, protein content, and blast resistance. Delta-p/G-BLUP index had higher predictive abilities for the traits studied, except for amylose content trait in which the method with the highest predictive ability was BayesCpi, being approximately 3% greater than that of the Delta-p/G-BLUP index.

RESUMO: A cultura do arroz tem grande importância nacional e mundial por ser um dos cereais mais produzidos e consumidos no mundo, caracterizando-se como o principal alimento de mais da metade da população mundial. Em função de sua importância alimentar, desenvolver métodos eficientes que visam a predição e a seleção de indivíduos geneticamente superiores, quanto a características da planta, é de extrema importância para os programas de melhoramento. Diante disso, o objetivo deste trabalho foi avaliar e comparar a eficiência do método Delta-p, G-BLUP, BayesCpi, BLASSO e o índice Delta-p/G-BLUP, índice Delta-p/BayesCpi e índice Delta-p/BLASSO, na estimação de valores genômicos e dos efeitos de marcadores SNPs (Single Nucleotide Polymorphisms) em dados fenotípicos associados a características de arroz. A utilização de marcadores moleculares permite alta eficiência seletiva e o aumento do ganho genético por unidade de tempo. O método Delta-p utiliza o conceito de mudança na frequência alélica devido à seleção e o conceito teórico de ganho genético. O Índice é baseado no princípio da seleção combinada, utiliza conjuntamente as informações dos valores genômicos aditivos preditos via G-BLUP, BayesCpi ou BLASSO e via Delta-p. Estes métodos foram aplicados e comparados quanto à predição genômica utilizando nove características de arroz (Oryza sativa), sendo elas: comprimento da folha bandeira, largura da folha bandeira; número de panículas por planta; número de ramos da panícula primária; comprimento de semente; largura de semente; teor de amilose; teor de proteína; resistência a bruzone. O índice Delta-p/G-BLUP obteve maiores capacidades preditivas para as características estudadas, exceto para a característica Conteúdo de amilose, em que o método que obteve maior capacidade preditiva foi o BayesCpi, sendo aproximadamente 3% superior ao índice Delta-p/G-BLUP.

Laparoscopic ovum pick-up for in vitro embryo production from dairy bovine andbuffalo calves

Laparoscopic ovum pick-up (LOPU) conducted on bovine and buffalo calves of 2-6-month of age, followed by in vitro embryo production and transfer into synchronous adult recipients, is a powerful tool for accelerated genetic gain and early dissemination of top genetics. In its current state, the technology is characterized by higher oocyte recovery rates, lower oocyte-to-embryo yields, and similar pregnancy and term development rates compared with adult counterparts. Improvements in oocyte competence have been made in recent years mainly through gonadotropin stimulation protocols tailored for prepubertal donors. These advances have brought the technology to the point of been apt for commercial application. However, future research must focus on increasing the proportion of fully competent oocytes recovered from calves thereby further empowering the role this technology platform can play in programs for accelerated dissemination of superior genetics.(AU)

Laparoscopic ovum pick-up for in vitro embryo production from dairy bovine andbuffalo calves

Laparoscopic ovum pick-up (LOPU) conducted on bovine and buffalo calves of 2-6-month of age, followed by in vitro embryo production and transfer into synchronous adult recipients, is a powerful tool for accelerated genetic gain and early dissemination of top genetics. In its current state, the technology is characterized by higher oocyte recovery rates, lower oocyte-to-embryo yields, and similar pregnancy and term development rates compared with adult counterparts. Improvements in oocyte competence have been made in recent years mainly through gonadotropin stimulation protocols tailored for prepubertal donors. These advances have brought the technology to the point of been apt for commercial application. However, future research must focus on increasing the proportion of fully competent oocytes recovered from calves thereby further empowering the role this technology platform can play in programs for accelerated dissemination of superior genetics.

Economic values and selection index in different Angus-Nellore cross-bred production systems.

Bioeconomic models were developed to calculate economic values (EV) for economically important traits in beef cattle, to evaluate the impact of these traits on production profitability, to assess possible market changes with a payment system and to develop economic selection indexes for Angus cattle for two production systems. Two beef cattle production systems were simulated as follows: a cow-calf cycle (CC) and a complete cycle (CoC). Following selection, positive changes in the EV were observed. In the CC, each 1.0% increment in weaning weight (WW), weaning rate (WR) and pregnancy rate (PR) resulted in increases in US$ 1.30, US$ 3.68 and US$ 3.55 per cow/year in profit, respectively. In the CoC, EV of US$ 1.01, US$ 1.79, US$ 1.19, US$ 1.34, US$ 6.84 and US$ 7.86 per cow/year were obtained for WW, year weight, yearling weight, final weight, WR and PR, respectively. The payment system for carcass quality showed that the scenario considering that 100% of the animals displayed uniform carcasses exhibited the highest EV and was considered optimal. Considering the sensitivity analysis, the price paid per animal was the factor that most affected the EV in both systems. The selection indexes obtained may be used in similar production systems, and the use of EV and selection indexes are important tools for any production system with positive change in profit after selection.