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The study of adaptability, stability, and productivity is essential for selecting and recommending superior genotypes. This fact is particularly the case for the introduction of common bean cultivars in Rio de Janeiro, Brazil, whose production is negligible and does not meet the internal demand. Thus, this study estimated genetic parameters and selection gains and undertake a simultaneous selection for adaptability, stability, and productivity in black bean genotypes via mixed models. The investigation was carried out in three municipalities in the state of Rio de Janeiro during three crop years. The trials were set up in a randomized block design with 11 genotypes and three replications. High mean heritability (81%) and selection accuracy (90%), as well as good selection prospects, were observed. Gains between 1.03 and 9.49% were achieved for grain yield. Simultaneous selection was efficient, indicating two black bean lines (CNFP 15290 and CNFP 15361) as the most productive, adaptable, and stable. As such, these lines have the potential to be released as new black bean cultivars for the state of Rio de Janeiro. [ABSTRACT FROM AUTHOR]

The study of genotypic relationships between drought tolerance indices and agronomic traits of interest in wheat breeding is useful for designing selection strategies. The objective of this research was to investigate the cause-and-effect relationships between agronomic traits and drought tolerance indices through the analysis of canonical correlations. Two trials (control and stress) were conducted in winter 2020 in Viçosa, MG, Brazil. The traits evaluated were: (days for heading, plant height, mass and number of grains per spike, mass of one hundred grains, and grain yield). Grain yield data from the control and stress conditions were used to construct five drought tolerance indices. The data were subjected to mixed model analysis for estimation of genetic parameters and prediction of genotypic values (REML/BLUP), and then the genotypic values were used to calculate the correlation coefficients between the traits. Two groups of traits were established for the study of canonical correlations, the first group consisting of agronomic traits and the second by drought tolerance indices. There was a significant genotype effect for all evaluated traits. The canonical pairs were significant, which indicated the existence of dependence between the groups. Days to heading trait can be used in the indirect selection of wheat genotypes for drought tolerance. [ABSTRACT FROM AUTHOR]

This study carried out early selection of soybean progenies that are productive and resilient to environmental conditions. The experiment took place at the Genetic Breeding Program of UNIJUI (University of the Northwest of the State of Rio Grande do Sul), located in Ijuí - RS, Brazil. The experiment used augmented blocks design with interim checks. The regular treatments correspond to 24 soybean F2 populations and the common treatments were 18 commercial checks, arranged in four replications. At full physiological maturity, in each experimental unit, five plants were randomly collected to obtain seed weight per plant (SWP, g). The Jinks and Pooni methodology was used to calculate the probability of extracting superior lineages from the evaluated populations. The best control and promising cultivars to compose the parent bank are BMX FORÇA RR, FUNDACEP 66 RR and TMG 7062 IPRO. Jinks and Pooni's methodology identified populations IRC001, IRC002, IRC017, IRC019, IRC028, IRC030, IRC032, IRC033, IRC035, IRC036, IRC039 and IRC040 as having high potential for extraction of superior lineages. [ABSTRACT FROM AUTHOR]

Germplasm collections for breeding purposes must initially be characterized to evaluate the diversity and allow the selection of materials for specific environments and uses. Stylosanthes scabra Vog. is a legume forage from the Brazilian Tropical Semiarid region, which might have potential, but is still underknown. The treatments consisted of eight S. scabra accesses (F1 generation) from Bom Jardim Municipality, in the tropical semiarid region in Brazil, on a complete randomized block design, with three replications. Qualitative and quantitative morphological descriptors and anthracnose incidence were evaluated at 30-day intervals, while forage mass was evaluated through cuts every 60 days, totaling three cuts. Frequency analysis by access was performed on qualitative variables and analysis of variance and Friedman on quantitative variables with subsequent Tukey test (p < 0.05) when appropriate. Genetic parameters were estimated for qualitative and quantitative descriptors. The accesses of S. scabra were different (p < 0.05) for all evaluated descriptors except for plant height, with high heritability (> 62.8%) and low repeatability (0.2 to 0.6). The high morphological diversity, even on a relatively small collection from a single tropical semiarid municipality, indicates the possibility of selecting superior materials. [ABSTRACT FROM AUTHOR]

Resumo O presente trabalho objetivou estimar parâmetros genéticos e avaliar o desempenho das progênies (linhagens) de Leucena leucocephala [(Lam.) De Wit], com vistas à seleção do melhor material genético, para uso em diversos sistemas de produção. Trinta linhagens foram plantadas em forma de teste de progênie na Reserva Indígena Kaiowá e Guarani, em Caarapó/MS, sob delineamento de blocos ao acaso, com cinco repetições e dez plantas por parcela. Aos 13 meses de idade, foram avaliados os caracteres: altura total da planta e diâmetro do coleto. Os resultados demonstraram haver baixa variabilidade genética para os caracteres estudados, o que sugere que as 30 progênies podem ser oriundas de uma ou poucas linhagens ou cultivares. As estimativas de herdabilidades individuais foram de baixas magnitudes (3,38% a 5,13%) para os caracteres estudados. As herdabilidades da média de linhagens apresentaram moderadas magnitudes e podem proporcionar progressos genéticos consideráveis em resposta à seleção. Os resultados obtidos permitiram identificar as 4 melhores linhagens, porém para a continuidade do programa de melhoramento é necessário ampliar a base genética do material.

RESUMO Em um teste de progênies de grevilea (Grevillea robusta A. Cunn), objetivou-se estimar os parâmetros genéticos e ganhos genéticos por seleção para altura de plantas, do primeiro ao quarto ano de idade de plantio. Detectaram-se diferenças significativas entre progênies e as estimativas de herdabilidade revelaram moderado controle genético para o caráter e, conseqüentemente, possibilidades de ganhos consideráveis com a seleção entre e dentro de famílias. Houve variações ao longo dos anos nas estimativas, exceto para as médias e variâncias. Não se observou a estabilização nos valores dos parâmetros, sugerindo-se a continuidade da experimentação por mais tempo, para inferência seguras.

Background: Climatic conditions in tropical countries have a significant effect on milk production. Aim. Analyze the climatic conditions at the Los Naranjos Genetic Livestock Company and its possible relationship with the behavior of milk production at 305 days. Materials and methods: A database of 12,625 milk production records was available, from cows that gave birth between the years 2002 -2020, which corresponded to 7,711 animals. There were monthly records of the minimum temperature (Tmin), average (Tmed) and maximum (Tmax) at 0C, relative humidity (RH) in % and the temperature-humidity index (ITH) was generated, and from this the performed the calculation of the Accumulated Caloric Load (CCA) for the three months before delivery. In addition, heritabilities (h2) and genetic correlations (rg) were estimated for the different CCAs. Results: The general means obtained were: PL305: 1 624.45 ± 360.40 (kg/lactation), ITH 76.34 ± 18.70 and CCA 229.21 ± 128.5. All sources of variation studied significantly influenced milk production at 305 days. The h2 ranged between 0.25 and 0.38 and the rgs were all positive and higher for the closer CCA groups. Conclusions: There was an inverse relationship between ITH and CCA with milk production. Additive genetic variability is evident for the different CCA groups and the rg were positive denoting certain genetic variability for adaptation to climatic stress. [ABSTRACT FROM AUTHOR]

Antecedentes: Las condiciones climáticas en los países tropicales, ejercen un efecto significativo, sobre la producción de leche. Objetivo. Analizar las condiciones climáticas en la Empresa Pecuaria Genética Los Naranjos y su posible relación con el comportamiento de la producción de leche a 305 días. Materiales y métodos: Se dispuso de una base de datos de 12 625 registros de producción de leche, de vacas que tuvieron sus partos entre los años 2002 -2020 que se correspondieron con 7 711 animales. Se contó con los registros mensuales de la temperatura mínima (Tmin), media (Tmed) y máxima (Tmáx) en 0C, humedad relativa (HR) en % y se generó el índice temperatura-humedad (ITH), y a partir de este se realizó el cálculo de la Carga Calórica Acumulada (CCA) de los tres meses antes del parto. Además, se estimaron las heredabilidades (h2) y las correlaciones genéticas (rg) para las diferentes CCA. Resultados: Las medias generales obtenidas fueron: PL305: 1 624,45 ± 360.40 (kg/lactancia), ITH 76,34± 18,70 y CCA 229,21± 128,5. Todas las fuentes de variación estudiadas influyeron en forma significativa en la producción de leche a 305 días. Las h2 variaron entre 0,25 y 0,38 y las rg fueron todas positivas y más altas para los grupos de CCA más próximos. Conclusiones: Hubo relación inversa entre el ITH y la CCA con la producción de leche. Se evidencia la variabilidad genética aditiva para los diferentes grupos de CCA y las rg fueron positivas denotando cierta variabilidad genética para la adaptación al stress climático.

This study aimed to assess and compare the behavior of superior genotypes of Coffea canephora in terms of fruiting capacity using directed hybridizations in a full diallel design with reciprocals. Hybridizations were performed using 12 possible combinations between genotypes 02, 03, 23 and 83 from the Incaper breeding program. High estimates of the genotypic coefficient of determination in terms of the total number of pinheads per cross (TNP) and fruit set (FS) indicated variability of genetic nature. FS averaged 52,27 %, ranging from 31,32 % to 82,09 %, with the higher rates relating to clone 23 as the male parent. Differences were found between reciprocal crosses in the combinations with genotype 23, which emerged as the donor plant with the best fruiting rate, but poor receiving ability. Clone 83 prevailed as the best receiving plant and the least effective donor. In the comparison of these two genotypes, antagonism was observed in their behavior when they were used as pollen-donor plants (male parents) and pollen-receiver plants (female parents), highlighting their possible maternal effect. Crosses involving clones 02 and 03 showed no differences when used reciprocally. The estimates of genotypic correlations were negative for the four associations involving the FS characteristic, being of greater magnitude with TNP. [ABSTRACT FROM AUTHOR]

Copyright of Ciência Florestal (01039954) is the property of Ciencia Florestal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Litter size at birth (LSB) is one of the most important economic traits in sheep and could be used in genetic improvement schemes for meat production. LSB is inherently a categorical trait and should be analysed with threshold models. Objective: Bayesian threshold models were used to analyze sheep LSB to estimate genetic parameters. Methods: Data was based on 7,901 LSB records from 14,968 dams and 682 sires collected from 1986 to 2012 at Makouie Sheep Breeding Station in Iran. Means of posterior distributions (MPDs) of LSB's genetic parameters were estimated, and the best-fitted models were selected using the deviance information criterion. Results: In the repeated measurement analysis, the estimated direct and maternal heritabilities, and permanent environmental effect (±SE), according to the best-fitted model (model 5), were 0.01 (0.010), 0.02 (0.014), and 0.01 (0.011), respectively. In the univariate analysis, the best estimates of direct and maternal heritabilities were 0.12 (0.064) and 0.08 (0.045), respectively. An increasing trend for direct and maternal heritabilities was observed in parity 2 (0.15 (0.082) and 0.25 (0.083), respectively). In the bivariate analysis, the best estimates of direct and maternal heritabilities for LSB were 0.03 (0.027) and 0.22 (0.041), respectively. The direct and maternal genetic correlations among parities were 0.25 (0.054) and 0.12 (0.021), respectively. Conclusions: The results showed a considerable influence of environmental factors on LSB in each parity of sheep; also, statistically different genetic parameters (p<0.05) were obtained from one parity to another, indicating the different and large influences of genetic and environmental factors for each parity. [ABSTRACT FROM AUTHOR]

[Introducción]: Gmelina arborea se ha consolidado como la segunda especie más utilizada en la reforestación comercial en Costa Rica. [Objetivo]: Evaluar el comportamiento de clones G. arborea en condiciones de suelo ácidos. [Metodología]: Se utilizó un diseño experimental de bloques completos al azar, con 6 repeticiones, 29 clones y 5 testigos, con un distanciamiento de 4 x 4 m. Se realizó un análisis del suelo y se calcularon parámetros genéticos a diferentes edades, para las variables diámetro a la altura del pecho (DAP), altura y volumen comercial, utilizando el software SELEGEN, el cual se basa en el método REML/BLUP; asimismo, se realizaron correlaciones genéticas entre las variables evaluadas. [Resultados]: El análisis del suelo reflejó deficiencias nutricionales de elementos esenciales para el desarrollo de la melina, un pH menor a 5.5, altos contenidos de hierro (Fe) y saturación de aluminio (Al) elevado. Los mayores coeficientes de heredabilidad individual y media del clon se presentaron a la edad de 4.5 años, donde el DAP es el carácter que presentó mayores valores. Las mayores correlaciones genéticas se presentaron entre las variables DAP-volumen comercial a partir de los 3.5 años. Se evidenció que existen 10 clones que mejor se adaptaron a las condiciones del sitio, presentando mayores crecimientos en las variables dasométricas, con ganancias genéticas dentro del rango de 12.7 % y 28 %, comparadas con la media general del ensayo y el material utilizado como testigo. [Conclusiones]: Se concluye que existe material genético de melina con potencial para adaptarse a condiciones de suelo ácidos.

La Gmelina arborea es una de las especies de mayor importancia en proyectos de reforestación comercial en Costa Rica y actualmente, forma parte importante del programa de mejoramiento genético en Costa Rica liderado por GENFORES. El objetivo del presente estudio consistió en determinar los parámetros genéticos de 54 clones de melina utilizados en un ensayo clonal en la región Caribe de Costa Rica. El ensayo se estableció con un diseño de bloques completos al azar con cuatro repeticiones por tratamiento, con un distanciamiento de 4 m x 3 m. Se calcularon parámetros genéticos a los 10, 22 y 34 meses, para las variables diámetro a la altura del pecho (DAP), altura comercial, volumen comercial y calidad del fuste, utilizando el software SELEGEN, el cual se basa en el método REML/BLUP, además, se realizaron correlaciones genéticas entre las variables evaluadas. Los resultados muestran mayor heredabilidad individual en sentido amplio para las variables de volumen comercial y DAP, además, reflejan que la calidad del fuste a los 22 y 34 meses presenta los mayores coeficientes de heredabilidad individual y heredabilidad media del clon. Las correlaciones genéticas reflejan valores altos y positivos entre las variables DAP-volumen comercial y altura comercial-calidad del fuste, a los 34 meses de edad, con un 0.97 y 0.74, respectivamente. Los clones 17 y 34, mostraron ser los mejores en el ranking genético en términos de volumen comercial; el material de control y el clon 19, fueron los que se ubicaron en las últimas posiciones del ranking. Se obtuvo una ganancia genética a los 34 meses de edad de 6.11 % y 9.36 % en DAP y volumen comercial, respectivamente. Se concluye que existe variabilidad genética en los materiales genéticos utilizados, que permiten obtener ganancias genéticas importantes, sobre todo si se utilizan los primeros 10 clones del ranking genético de las accesiones evaluadas.

Os modelos de regressão aleatória (MRA) aplicando funções B-spline são uma alternativa para modelar pesos do nascimento até a idade adulta dos animais, pois estas funções são menos vulneráveis as dificuldades constantemente observadas em outras metodologias. No entanto, são escassas pesquisas sobre aplicação destas funções sobre as características de crescimento em bovinos Nelore Mocho. Funções polinomiais de diferentes ordens e números de segmentos foram avaliadas na modelagem dos efeitos associados à curva de crescimento de bovinos da raça Nelore Mocho. Foram utilizados 15.148 registros de peso de 3.115 animais com idade entre 1 e 660 dias, criados na região norte do Brasil e nascidos entre 1995 e 2010. Os efeitos aleatórios foram modelados usando polinômios do tipo B-splines. Como efeitos aleatórios, foram considerados os efeitos genéticos aditivo direto e materno e os efeitos de ambientes permanentes direto e materno. Foram considerados como efeitos fixos, os grupos de contemporâneos, a idade da vaca ao parto (efeito linear e quadrático) e os polinômios de Legendre de quarta ordem, representando a curva média de crescimento. O resíduo foi modelado por meio de sete classes distribuídas segundo a idade. O modelo que considerou funções B-splines cúbicas com quatro nós para o efeito genético aditivo direto e três nós para os efeitos genético materno, ambiente permanente animal e ambiente permanente materno (C6555) foi o mais adequado. Concluiu-se que funções de covariâncias sob polinômios B-splines são eficientes e podem ser utilizados como alternativas para modelar a curva de crescimento de bovinos da raça Nelore Mocho do nascimento até 660 dias de idade.

El objetivo de este estudio fue estimar el valor de heredabilidad del carácter intervalo entre partos en una población de 2.112 vacas Romosinuano, y determinar los factores responsables de la variación de este carácter mediante el modelo lineal mixto generalizado. Se analizaron 7.560 registros de intervalo entre partos en el periodo 1936-2016. La media del intervalo entre partos fue de 379,74 ± 49,22 días (CV = 12,96 %) y las clases mes de parto, número de intervalo entre partos y año de parto tuvieron un efecto estadísticamente significativo sobre este carácter. Los menores intervalos entre partos ocurrieron entre abril y junio (367,12 ± 46,06 días), en vacas de cuarto y quinto parto (373,93 ± 46,93 días), y entre los años 1956 y 1965 (370,48 ± 50,55 días). Los mayores valores se presentaron entre octubre y diciembre (388,92 ± 57,96 días) en vacas de segundo (389,70 ± 49,38 días) y tercer intervalo entre partos (382,18 ± 51,19 días) cuyo parto ocurrió en el periodo 1946-1955 (387,69 ± 56,75 días). La heredabilidad de este carácter fue de 0,0001 ± 0,002. Se concluye que la raza Romosinuano tiene eficiencia reproductiva; sin embargo, dada la baja heredabilidad del intervalo entre partos, la selección por este carácter tendrá un impacto relativamente bajo debido al efecto de factores ambientales sobre su variación. El modelo lineal mixto generalizado es una herramienta que permite este tipo de estudios.

Copyright of Revista Mexicana de Ciencias Agrícolas is the property of Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this search was to quantify the genetic variability in progenies from grápia mother trees in natural populations, for initial growth characters of the seedlings. Seeds were collected from 13 mother trees, from four origins, located in the municipalities of Pareci Novo, São José do Sul and Aratiba in RS, and Seara in SC, as well as data from plants and place of origin. Biometrics were performed on 100 seeds lot from each mother tree, and an experiment was installed to evaluate progenies in a completely randomized design. It was evaluated the seedling emergence speed and the emergence percentage, the stem diameter and seedlings height, as well as the final survival percentage. A significative difference was found for all variables observed for seeds and seedlings of grápia mother trees. Seed length and width demonstrated high values for individual heritability in the narrow sense (above 0.6), being possible to use the seed size for an analysis of genetic variability between plants of the species, but not as an indicative variable of physiological quality and vigor. The correlation analysis indicated that the seedling emergence percentage is related to the characteristics of the mother plant plant (height and diameter). Thus, the use of seedlings for forest restoration areas is appropriate, as they have indications of genetic diversity. [ABSTRACT FROM AUTHOR]

Antecedentes: La interacción genotipo ambiente (IGA) implica que existe un cambio de orden de mérito bajo diferentes condiciones ambientales, y esto puede ser importante desde el punto de vista económico y práctico. El objetivo fue determinar la posible existencia de IGA en ganado bovino de la raza Santa Gertrudis en Cuba. Métodos: Se dispuso del peso a los 18 meses de edad de machos y hembras, que fue ajustado a 540 días de edad (PA), de 3 empresas ganaderas, con 4 529 animales que nacieron entre los años 1981- 2016, hijos de 161 sementales. Los datos se depuraron, eliminando aquellos sementales con menos de 10 hijos y grupos contemporáneos (GC) con menos de tres animales. Se conformaron dos grupos de datos, aquellos con peso final ajustado alto (PAA) y bajo (PAB) que estaban por encima y por debajo de la media, respectivamente. Se utilizó un modelo animal unicarácter considerando como efectos fijos el GC (rebaño-año-época) y el sexo y como efecto aleatorio el animal y el residuo. Un modelo bicarácter incluyó los mismos efectos, considerando PAA y PAB como dos rasgos independientes. Para aquellos sementales representados en los dos ambientes se estimaron las correlaciones de Pearson y Spearman entre sus valores genéticos. Resultados: Las heredabilidades (h2) para el unicarácter fueron: 0,37 ± 0,09 y 0,14 ± 0,04 y para el bicarácter: 0,22 ± 0,09 y 0,11 ± 0,04, para PAA y PAB, respectivamente. La correlación genética fue 0,82 pero las correlaciones de Pearson y Spearman: 0.04 y 0.18, indicaron que existe variación en el orden de mérito de los sementales y existencia de IGA. Conclusiones: Las heredabilidades para PA fueron moderadas y superiores para las mejores condiciones independientemente del modelo, Se demuestra que bajo esta metodología ambientes contrastantes presentan evidencia de IGA al producirse cambios en el orden de mérito de los sementales.

RESUMO Utilizaram-se registros de pesos corporais padronizados aos 120, 210, 365 e 450 dias de idade, provenientes de 30.481 animais da raça Nelore, progênies de 211 reprodutores acasalados com 19.229 matrizes, oriundos de rebanhos dos estados de Mato Grosso, Mato Grosso do Sul e Goiás, com o objetivo de avaliar a presença de interação genótipo x ambiente entre os estados. As estimativas de herdabilidade entre os estados variaram de 0,09 a 0,14; 0,11 a 0,17; 0,16 a 0,27 e 0,17 a 0,35, respectivamente, para os pesos 120, 210, 365 e 450 dias de idade. As estimativas de correlação genética aditiva entre a mesma característica para os diferentes estados apresentaram valores inferiores a 0,80. As correlações de Spearman entre os valores genéticos para os pesos corporais se reduziram à medida que se aumentou a intensidade de seleção sobre os reprodutores. A presença de interação genótipo x ambiente causa maior impacto sobre a avaliação genética dos reprodutores sob intensidade de seleção elevada, sendo interessante sua consideração no processo de avaliação genética. Estimativas de tendências genéticas para todos os pesos corporais apresentaram-se crescentes ao longo dos anos nos três estados.

La teca es una especie comercial de alto interés, principalmente por las propiedades físico-mecánicas de su madera, tasas de crecimiento y adaptabilidad. El objetivo del estudio fue evaluar la variación genética de rasgos de crecimiento y calidad del árbol entre 40 familias de polinización abierta. Usando datos de un ensayo de progenies de cuatro años, se calcularon heredabilidades en sentido estricto, ganancias genéticas, correlaciones genéticas y se construyó un ranquin de familias de acuerdo con el volumen total de madera por hectárea. Las familias mostraron una supervivencia alta entre 73-100 %. Las ganancias genéticas seleccionando 30 % de las mejores familias fueron de 2.93 % para diámetro, 4.83 % para volumen del fuste, 11.97 % para volumen por hectárea, 6.53 % para área de proyección de copa, 4.26 % para ángulo de inserción de ramas y 14.42 % para número de renuevos. Se identificaron tres familias con productividad superior y potencial para el establecimiento de plantaciones de alto rendimiento.

El objetivo del estudio fue estimar la repetibilidad del intervalo entre partos y establecer la relación con diferentes caracteres de eficiencia reproductiva de hembras Romosinuano. Una base de datos con 3.112 registros útiles de 871 hembras, colectados en el periodo 1936-2016, y provenientes del hato de conservación del Sistema de Bancos de Germoplasma de la Nación para la Alimentación y la Agricultura, del centro de investigación Turipaná, fue analizada. El modelo empleado para calcular los componentes de varianza necesarios para estimar el valor de repetibilidad del intervalo entre partos consistió en un modelo animal de medidas repetidas en el tiempo. Los componentes de varianza fueron estimados usando paquete rptR del software R, especializado en el análisis estadístico de datos. Con base en el valor estimado de la repetibilidad, se calculó y correlacionó el valor genético y la capacidad más probable de producción para cada hembra. Los valores promedio estimados del intervalo entre partos, la repetibilidad, la eficiencia reproductiva y la correlación entre el valor genético y la capacidad más probable de producción fueron 379,74 ± 47,74 días, 0,02 ± 0,01, 96 % y 93,7 %, respectivamente. La repetibilidad estimada para el intervalo entre partos fue baja, lo que demuestra también una baja correlación entre los intervalos de las hembras del hato analizado. La alta eficiencia reproductiva de la raza Romosinuano indica una gran adaptación al medio ambiente y la perfila como una oportunidad de mejora reproductiva del hato nacional mediante cruzamiento con otras razas.

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Copyright of Revista Colombiana de Ciencias Hortícolas is the property of Revista Colombiana de Ciencias Horticolas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We aimed to estimate genetic parameters for the non-linear Gompertz growth curve parameters based on the two-step method and simulated data of a pig population. Data of true breeding values, growth curve parameters (a, b and k) and body weights at 1, 90, 210, 360 and 540 days of age were simulated for 1700 individuals. Afterwards, in the first stage of the two-step method, the Gompertz curves were fitted for each animal and the growth curve parameters were estimated. In the second step, considering the estimated parameters as phenotypes, animals' breeding values were predicted by multitrait analyses. The simulation and two-step processes were replicated 10 times. For each replicate, the genetic parameters, accuracies and biases were calculated. Moderate to high average heritabilities for the curve parameters [0.62 (0.04), 0.56 (0.04) and 0.57 (0.04) for a, b and k, respectively] show the possibility of effective selection of animals based on these parameters. High and favorable average genetic correlations, especially between the most important growth curve parameters [a and k, 0.93 (0.01)], shows that selection for increased mature weight (a) will also increase maturation rate (k). High average accuracies [0.84 (0.02), 0.82 (0.02) and 0.83 (0.02)] and low average biases [0.06 (0.06), 0.06 (0.06) and 0.07 (0.07) for a, b, and k, respectively] indicate that the two-step approach is feasible for predicting breeding values for growth curve parameters and for dealing with longitudinal body weight measurements. [ABSTRACT FROM AUTHOR]

Introducción. La edad de selección temprana permite acelerar los programas de mejoramiento genético y optimizar la producción forestal, en este caso con melina (Gmelina arborea), la cual es la segunda especie forestal más importante para la reforestación comercial en Costa Rica. Objetivo. Determinar la edad óptima de selección de melina en Costa Rica, mediante la evaluación de cuatro caracteres genéticos. Materiales y métodos. El estudio se llevó a cabo en Siquirres y Pérez Zeledón, región Caribe y zona sur de Costa Rica, respectivamente. Se utilizó un diseño de bloques completos al azar con cuatro repeticiones (sitios 1 y 3) y seis repeticiones (sitio 2) por tratamiento. El distanciamiento inicial fue de 4 m x 3 m para el ensayo del El Porvenir y de 4 m x 4 m para los ensayos de Siquirres y La Ceniza. Se calcularon parámetros genéticos a diferentes edades, para las variables diámetro a la altura del pecho (DAP), altura comercial, volumen comercial y calidad del fuste, con el software SELEGEN, el cual se basa en el método REML/BLUP, además, se realizaron correlaciones genéticas entre las variables evaluadas. Resultados. El DAP y el volumen comercial fueron los caracteres con mayor control genético, presentaron los mayores valores promedio de heredabilidad individual y media clonal, entre los 2,8 y 4 años de edad. Las mayores correlaciones genéticas (>80 %), entre las variables DAP y volumen comercial, se presentaron a partir de los 2,8 años de edad, que aumentan en edades posteriores hasta alcanzar valores mayores a 90 %. Conclusión. Pudo determinarse el rango entre los 2,8 y 4 años, como posible edad de selección genética para melina.

Meat goat breeding programs should prioritize the identification and selection of genetically superior animals for traits related to meat quality and carcass yield in order to increase the value of the final product. Objective: To estimate (co)variance components and genetic parameters for ultrasound-measured carcass traits, body size and body weight in Anglo- Nubian breed goats raised in the Mid-North region of Brazil. Methods: (Co)variance components and genetic parameters were estimated using the single and two-trait animal model analyses via Bayesian inference for loin eye dimensions (area, length, and depth), sternal fat thickness, rump height, chest circumference and depth, leg perimeter, and body weight. Results: Heritability estimates were higher when two-trait analyses were used. This finding implies that it is possible to recover part of the additive genetic variance included in the residual variance due to the correlation between traits. Genetic correlations between carcass and body size traits showed different magnitudes. On the other hand, genetic correlations between the traits related to muscularity showed high magnitudes. Conclusions: Body weight was not a good indicator of muscularity; therefore, it is not recommended as a criterion for indirect selection to improve carcass traits of Anglo-Nubian goats. Leg perimeter and chest circumference may be important to construct selection indexes in meat goat breeding programs. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ciencia y Tecnología Agropecuaria is the property of Agrosavia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introducción. La selección de genotipos con hábito de crecimiento determinado en tomate, debe contemplar criterios adecuados de selección para incrementar la eficiencia del programa de fitomejoramiento. Objetivo. El objetivo de este trabajo fue estimar criterios de selección para líneas de tomate tipo “chonto” con hábito de crecimiento determinado. Materiales y métodos. Este trabajo se llevó a cabo en la Universidad Nacional de Colombia (Sede Palmira), en el año 2016, con siete líneas con hábito de crecimiento determinado y un testigo con crecimiento indeterminado. Se determinó la heredabilidad en sentido amplio (h2g), coeficiente de variación ambiental, coeficiente de variación genética, eficiencia de la selección y ganancia genética, en parámetros morfológicos, fenológicos, de calidad de fruto, forma de fruto y producción, con el empleo del procedimiento RELM/BLUP, del software SELEGEN. Resultados. Hubo tres rangos de h2g, el primero con valores de h2g mayores a 0,76, el segundo entre 0,53 y 0,38, y el tercero con un valor menor a 0,38. Los mayores valores de h2g fueron para altura final de planta con 0,92, altura de planta al momento de la cosecha con 0,88, producción por planta con 0,83, días a floración con 0,83, número de frutos por planta con 0,82, y días a cosecha con 0,82. Para ganancia genética se encontró que el testigo presentó los mayores valores para, altura final de planta, altura de planta a cosecha, longitud de entrenudo, días a cosecha, duración de cosecha, contenido de sólidos solubles, número de frutos por planta, peso de fruto y producción por planta; sin embargo, en algunos parámetros como altura y fenología para selección por hábito de crecimiento determinado, resultaron mejores los valores más bajos. Conclusión. Se evidenciaron parámetros genéticos que podrían considerarse como criterios de selección para líneas de tomate tipo “chonto” con hábito de crecimiento determinado.

Bactris gasipaes Kunth é uma das poucas palmeiras domesticadas cujos frutos possuem grande variabilidade natural de cores, sabores, oleosidade e textura. No entanto, por não existirem cultivares desenvolvidas para a produção de frutos, essa mesma variabilidade limita o seu mercado, uma vez que os frutos adequados para consumo direto, produção de farinha ou de óleo têm diferentes características. Nesse sentido, o objetivo deste trabalho foi quantificar o progresso genético com a seleção entre e dentro de progênies para a produção de frutos de pupunha. Para o estudo foram avaliadas 14 progênies de meios-irmãos em delineamento em blocos ao acaso com três repetições de oito plantas por parcela, no espaçamento de 6 m x 4 m, no 5º, 6º e 7º anos de cultivo. Os parâmetros genéticos mostraram que a pupunheira tende a estabilizar sua produção a partir do 7º ano de cultivo. A seleção dos três melhores indivíduos por família proporcionou a manutenção do número efetivo associado a uma menor redução no ganho de seleção. A estimativa do ganho de seleção com a propagação vegetativa foi aproximadamente 50% superior ao ganho estimado com a propagação por sementes. Os ganhos de seleção da produção de frutos no 7º ano de cultivo, considerando a propagação por sementes e a clonagem, foram de 35,58% e 58,58%, respectivamente.

En la ganadería de lidia, la selección está en función del desempeño del toro durante la lidia. Posición de la cabeza (PC) y de las manos (PM), recorrido del toro (RE) y modo de finalizar (FI) la embestida define el desempeño del toro, y pueden ser considerados como criterios de selección. El objetivo fue estimar heredabilidades (h2) y correlaciones genéticas (rg) para PC, PM, FI y RE; y construir dos índices de selección: IS1 con valores relativos de un análisis factorial, IS2 con valores relativos a partir de la desviación estándar de cada rasgo. Se calculó la respuesta a la selección (RS) y exactitud (EX) de cada IS. El número de observaciones (valor promedio ± desviación estándar) para PC, PM, RE y FI fue 984 (5.46 ± 1.4), 978 (2.93 ± 1.1), 981 (3.15 ± 0.7) y 785 (2.88 ± 1.1), respectivamente; con escalas de uno a siete para PC, y de uno a cinco para el resto de las variables. Para h2 y rg se realizó un análisis multivariado con el software MTDFREML. La h2 fue de 0.20 ± 0.06, 0.15 ± 0.05, 0.13 ± 0.03 y 0.17 ± 0.05 para PC, RE, PM y FI, respectivamente; todas las rg fueron positivas, de 0.57 a 0.94, con valor promedio de 0.753. IS1 = 0.068*PC + 0.048*RE - 0.012*PM + 0.088*FI; con EX de 0.46 y RS de 0.325. IS2 = 0.231*PC + 0.249*RE - 0.038*PM + 0.298*FI; con EX de 0.45 y RS de 1.15.

The objectives of this work were to evaluate the genotype-environment interaction, and estimate genetic parameters, genetic trends, and performance dissimilarity-weight gain from birth to weaning (WGBW), adjusted weight to 205 days (W205), weight gain from weaning to 18 months of age (WG18), and adjusted weight to 550 days (W550)-in Nellore animals born between 1986 and 2012, and raised in pasture-based system in three different environmental gradients in Brazil. Data of 62,001 animals-11,729 raised in the Alto Taquari/Bolsão region (ATBR), 21,143 raised in the Campo Grande/Dourados region (CGDR) and 29,129 raised in the western São Paulo/Paraná region (SPPR) in Brazil-were used. The contemporary groups were defined by sex, location, and birth year and season, with at least nine individuals, two different environments, and breeding bulls with at least five progenies. The statistical model contained the direct additive and residual genetic effects (random effects), and environmental and contemporary group effects (fixed effects). Genetic parameters, genotype-environment interaction and genetic trends were estimates using animal model (uni- and/or bi- traits). The level of similarity between regions was evaluated using principal components. The animals raised in the CGDR had superior performance regarding the traits evaluated. The direct heritability estimates ranged from 0.39 to 0.44 (WGBW), 0.41 to 0.45 (W205), 0.42 to 0.55 (WG18) and 0.60 to 0.62 (W550). The maternal heritability of the traits ranged from 0.20 (WGBW), 0.12 to 0.18 (W205), 0.00 to 0.06 (WG18) and 0.02 to 0.22 (W550). According to the Spearman correlation, the ranking of the breeding bulls in the regions evaluated were different. The mean of Euclidean distance indicated low similarity between ATBR and CGDR (43.20), and ATBR and SPPR (29.24). CGDR and SPPR presented similarity of 17.84. The breed values increased over the years in the traits evaluated. The cumulative variance percentage of the first two main components explained 99.99% variation among the regions, and the weight gains of the animals were the most important to differentiate the regions. A genotype-environment interaction was found for the traits evaluated, thus, the breeding bull selected with superior genetic merit for one region might not be the best for others.

Jatropha germplasm accessions need an assessment of their traits to evaluate the nature and magnitude of the genetic variability among accessions. The objective of this research was to evaluate the phenotypic behavior of 130 Jatropha curcas L. (Jatropha) accessions and the genetic variability of selected Jatropha accessions. The selected variables were assessed between 2008-2014 based on the number of fruits per tree (FP), the number of seeds per fruit (SpF), weight of 100 dry seeds (100SW), seed length (SL), seed width (SW), smallest deviation standard as regular seed production (RP), highest deviation standard as irregular seed production (IP), seed oil content (Oil), seed production in g per tree (SP). Correspondence Analysis techniques were also applied in selected elite Jatropha accessions. The genotypic and phenotypic correlation coefficient between seed length, seed width, 100-seed weight and oil content for selected Jatropha accessions were applied. Variance, genotypic and phenotypic coefficients of variation, heritability (broad-sense) and genetic advance were calculated for several Jatropha phenotypic characteristics. CP041, CP052, CP037, CP054, CP060, CP122, CP118, CP120, CP121 INIAP Jatropha accessions were selected basically for SP and FP. A high statistically significant correlation (genotypic and phenotypic) between seed length - seed width was obtained from the chosen Jatropha accessions. Genetic association in the characteristics of growth and production highlighted the low phenotypic diversity in the Jatropha Portoviejo Research Station (EEP) of the National Institute for Agricultural and Cattle Ranching Research (INIAP) germplasm bank. There is an urgent need to improve the germplasm resource by obtaining new accessions, mainly from countries considered as centers of origin of the species. [ABSTRACT FROM AUTHOR]

Water deficit causes a number of changes in plant development and physiology and is reported to be a trigger for eucalyptus dieback disorder. Dieback manifests itself in adult individuals, which hampers the selection of tolerant material and, therefore, means potential jeopardy to commercial plantings. Genetic parameters of phenotypic traits were estimated by the mixed model methodology (REML/BLUP), based on the observation of seedlings from twelve commercial eucalyptus clones grown under water stress. The water deficit was simulated by using polyethylene glycol (PEG 6000) and controlling the water depth administered to the plants for a period of 120 days. Among the evaluated anatomical and physiological characteristics, 10 biomarkers were selected for discriminating the clones, based on their differentiated and significant response among genotypes as well as relevant heritability and accuracy. The best-ranked clones demonstrated tolerance pattern in accordance to the empirical information in the production fields. Our results support the feasibility of early selection for selecting eucalyptus genotypes more tolerant to dieback and to water deficit. [ABSTRACT FROM AUTHOR]

Background: Somatic cell score is an important parameter to predict milk quality and health of cows. However, in countries like Brazil, this trait is still not selected on a large scale, and no genetic parameters are reported in the literature. Objective: To estimate the variance components and genetic parameters for somatic cell score, milk yield, fat yield, protein yield, fat percentage, and protein percentage in Holstein cows. Methods: Records from 56,718 animals were used to estimate variance components, heritability, and genetic correlations using a multi-trait animal model by the REML method. Results: The heritability estimates were 0.19 for somatic cell score, 0.22 for milk yield, 0.26 for fat yield, 0.18 for protein yield, 0.61 for fat percentage, and 0.65 for protein percentage. The estimates of genetic correlations among analyzed traits ranged from -0.50 to 0.82. Conclusion: The low heritability observed for somatic cell score indicates that selection for this trait should result in benefits related to animal health and milk quality, but only in the long term. The low correlation between productive traits and somatic cell score indicates that inclusion of somatic cell score in animal breeding programs does not interfere negatively with the genetic selection for milk yield or solids. [ABSTRACT FROM AUTHOR]

Phenotypic and genealogy date of Siboney de Cuba cows from 1984 to 2016 calving years was used. The goal of this study was to estimate the parameters and breeding values (VG) of production, reproduction and longevity traits. Besides to construct selection index (IS) using principal componente (CP) analysis. The VG of 6 425 cows were estimated for milk yield up to 305 days (VGL305), lactation length (VGDL), age at first calving (VGEp1), calving gestation interval (VGIPG), lifetime yields (VGLTV) y productive life (VGVP). The heredabilities for L305, DL, EP1, IPG, LTV y VP were of 0.16±0.01, 0.04±0.01, 0.04±0.01, 0.44±0.02, 0.05±0.01 y 0.01±0.01, respectively. The genetic correlation between L305 and DL was of 0.36, between EP1, IPG and LTV of 0.36, -0.42 and -0.36, and the VP with the others traits were low (-0.24 to 0.11). The 70.8% of the total variance of VG was explained for the CP1-3, doing the highest importance the CP1 (32.4%). Using CP, it is possible to select animals based on only two scores generated by PC1 and PC2 instead of the six VG. It was concluded that it is possible to construct IS based on CP in Siboney de Cuba bovine. Selection for VGL305 and VGDL with PC1 index could be done separately from selection for VGIPG, VGEp1 and VGLTV using PC2 index, and the VP could be improved independent of the other traits using their VG. [ABSTRACT FROM AUTHOR]

Objective. To estimate genetic parameters for weight at eight months of age (W8M), age at first calving (AFC) and first calving interval (FCI) using pedigree and genomic relationship. Materials and methods. Phenotypic data on 481, 3063 and 1098 animals for W8M, AFC and FCI were used, respectively. The genomic information came from a population of 718 genotyped animals with a density chip of 30,106 single nucleotide polymorphism markers (SNP). Univariate and bivariate models were used under the conventional (BLUP) and single step genomic best linear unbiased predictor (ssGBLUP) methodologies. Results. The heritabilities for W8M, AFC and FCI ranged from 0.25 to 0.26, from 0.20 to 0.22 and from 0.04 to 0.08, respectively. The AFC and FCI models under ssGBLUP slightly decreased the error and increased the additive genetic variance, respectively. Conclusions. The inclusion of genomic information slightly increases the accuracy of the genetic estimates in this population. However, a larger amount of genotyped animals and with a higher genetic relationship connectivity would allow breeders to increase the potential of the ssGBLUP methodology in Colombian Simmental cattle. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Ciencias Hortícolas is the property of Revista Colombiana de Ciencias Horticolas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Esta pesquisa teve por objetivo a seleção de clones de eucaliptos em teste em Grajaú-MA, Brasil, visando ao aumento na produtividade. Os caracteres avaliados foram diâmetro à altura do peito – DAP (cm) e altura – ALT (m). Para isto, um total de 130 clones, distribuídos em 20 blocos, com uma planta/parcela, foram mensurados aos quatro e cinco anos. Os procedimentos estatísticos foram o método do modelo misto para obter o melhor preditor linear não viesado (BLUP) e a máxima verossimilhança restrita (REML) para estimar os componentes de variância. Para clones e parcelas, os testes de razão de verossimilhança (LRT) foram significativos a 1% de probabilidade. A variabilidade genética foi alta e variou de 11,42% a 14,70% para DAP e 9,15% a 10,22% para ALT. Os coeficientes de variação relativa (CVr ) foram maiores que um para ambos os caracteres, mostrando que a seleção pode resultar em grandes e rápidos ganhos genéticos. No geral, os caracteres foram altamente acurados. As correlações genéticas (ˆ gr ) foram positivas, indicando a possibilidade de seleção indireta. Os resultados indicaram que o DAP deve ser usado preferencialmente em relação à ALT, e permitem concluir que os ganhos genéticos após a seleção são muito promissores. Os clones selecionados podem ser indicados para testes clonais piloto e/ou fase II em locais com condições ambientais similares às do local de teste. This research aimed to select clones of eucalypts under testing in Grajaú, MA, Brazil, in order to increase the wood productivity. The traits considered were diameter at breast height – DAP (cm) and height – ALT (m). For this purpose, a total of 130 clones, distributed across 20 blocks with one plant/plot, were assessed at the ages four and five years. The statistical procedures were the mixed model method to obtain the best linear unbiased predictors (BLUP) and the restricted maximum likelihood (REML) to estimate the components of variance. For clones and plots, the likelihood ratio tests (LRT) were significant at 1% of probability. The genetic variability was high and ranged from 11.42% to 14.70% for DAP and 9.15% to 10.22% for ALT. The coefficient of variation ratio (CVr ) was greater than one for both traits, showing that selection can result in large and rapid genetic gains. In general, the traits were highly accurate. The genetic correlations (ˆ gr ) were positive, indicating the possibility for indirect selection. The results indicated that DAP must be used preferentially in relation to ALT, and allow us to conclude that the genetic gains after selection are very promising. The selected clones can be indicated to pilot clonal tests and/or phase II to places with environmental conditions similar to the field trial.

The objective of this review is to provide an outlook of the main findings of the research associated with genetic evaluations of dairy cattle populations in Mexico, and to identify the work performed by researchers and opportunity areas for future research. The review included papers published in scientific journals for the last 20 years (1997-2017). The study topics are related with: effect of environmental factors, estimation of genetic parameters and genetic trends, flow of genetic material and genotype by environment interaction, and studies associated with molecular genetics. The estimation of genetic parameters has been extensively studied for milk yield, with estimators of sufficient magnitude to design and implement genetic improvement programs. Even though there is progress in the publication of studies related with genetic evaluations, the improvement of basic issues related with more complete and reliable databases, and with the use of predicted genetic values in national animal breeding programs is needed. It is required to document the study of more accurate methodologies of genetic evaluation, especially for populations and traits less studied.

Introducción: El programa de mejora del ganado Cebú de Cuba (PMGC) se lleva a cabo con aproximadamente 12000 hembras de raza pura, distribuidas en varios rebaños en todo el país. Se registra en los machos jóvenes, el peso al destete (PD); peso vivo a 18 meses (PF18), y en las hembras el intervalo entre partos (IPP), intervalo parto gestación (IPG), número de inseminación por gestación (NIA); duración de la gestación (DG) y tasa de gestación a la primera inseminación (TG). Sin embargo, hasta el presente sólo el PD y PF18 son los criterios de selección de mayor prioridad. El objetivo de éste estudio fue estimar los parámetros genéticos de estos caracteres y de acuerdo con los resultados hacer las sugerencias necesarias que posibiliten una mayor eficiencia del PMGC. Método: Un total de 28776 registros de IPP, IPG, NIA, DG, TG y PD, provenientes de 23808 animales fueron estudiados con diferentes modelos lineales mixtos con el propósito de estimar los componentes de (co)varianza y los parámetros genéticos de estos caracteres aplicando el software ASreml3 (Gilmour et al., 2009). Resultados: La edad al parto ejerció un efecto benéfico en todos los rasgos excepto en NIA. La heredabilidad (h2) para PD fue 0.45±0.05 y 0.21±0.03 para efectos directo y maternos, respectivamente, mientras que la correlación genética entre ambos efectos fue negativa (- 0.57±0.05); Las heredabilidades para IPP, IPG, NIA y TG fueron: 0.10±0.03; 0.10±0.03; 0.11±0.03 y 0.08±0.02, respectivamente. Los modelos bivariados, arrojaron incrementos del 4 al 18 % en la h2 para IPP (0.12±0.01); IPG (0.11±0.02) y NIA (0.12±0.03) y cerca del 45 % para TG (0.14±0.04), respecto a los estimados por modelos univariados. Los modelos multivariados mostraron un incremento del 18% en la precisión de los valores genéticos de los sementales. El análisis de componentes principales arrojó que los dos primeros eigenvalores (ei) explican entre el 93 al 99% de la varianza genética total y en un escenario de evaluación bicarácter mediante PD y IPP o PD con IPG, el segundo componente explicó cerca del 20% de la varianza entre los valores genéticos para estos rasgos. Con el uso de los coeficientes del segundo ei como índice de ponderación de los VG se pudieron identificar animales que mejoran simultáneamente tanto el PD y los rasgos reproductivos IPP o IPG. Discusión o Conclusión: La selección aplicando los coeficientes del primer y segundo eigenvalores producirá respuestas positivas en PD e IPP, atenuando los efectos antagónicos de los efectos directos y maternos sobre el peso al destete. Se recomienda aplicar modelos multivariados para incrementar la precisión de los estimados de parámetros genéticos de rasgos de reproductivos, debido a un mejor aprovechamiento de las (co)varianzas genéticas con caracteres de mayor nivel de heredabilidad.

Background: The existence of genotype-environment interaction (GEI) implies the occurrence of a change of merit order under different environmental conditions, which may be important from economic and practical standpoints. The aim of this study was to determine the possible existence of GEI in Santa Gertrudis cattle, in Cuba. Methods: The weights of 18-month old males and females were adjusted to 540 days of age (AW). The animals belonged to three cattle raising companies, with 4 529 animals born between 1981 and 2016, from 161 stud bulls. The data were narrowed down, excluding the studs with less than 10 descendants, and same-age group (SA) with less than three animals. Two data sets were made: animals with a high final adjusted weight (HAW), and animals with low adjusted weight (LAW), which were above and under the mean, respectively. A single-character animal model was used, considering SA (herd-year-season) and sex as fixed effects; animal and residue were deemed as a random effect. A two-character model had the same effects, including HAW and LAW as two independent traits. Regarding the stud bulls represented in the two environments, the Pearson and Spearman correlations were estimated among their genetic values. Results: The single-character heredities (h2) were, 0.37 ± 0.09, and 0.14 ± 0.04, and 0.22 ± 0.09, and 0.11 ± 0.04, in the two-character model for PAA and PAB, respectively. The genetic correlation was 0.82, but the Pearson and Spearman correlations were, 0.04 and 0.18, which indicated a variation in stud merit order and GEI. Conclusions: Heredities in the AW were moderate and higher under better conditions, regardless of the model. This methodology demonstrated that under contrasting environments there is evidence of GEI upon changes in stud merit order. [ABSTRACT FROM AUTHOR]

The prototype of Pura Raza Española horse depends on the equestrian disciplines and establishes the breeding selection objectives; the selection criteria are developed from zoometric measures (ZM), which are subject to multiple direct and maternal genetic effects. The objective of this study was to evaluate the magnitude of the maternal genetic effects, based on the (co)variances, if they are equal to or different from zero. Our database included information of 1806 equines born from 2004 to 2013, with data of eight ZM (mean in cm ± SD): thoracic perimeter (TP; 189.3±8.9), knee perimeter (KP; 32.3±1.8), cannon perimeter (CP; 20.4±1.3), scapular-ischial length (SIL; 160.7±5.9), chest width (CW; 43.1±3.0), height of the substernal space (HSS; 83.1±5.1), chest height (CH; 73.2±4.3), and withers height (WH; 157.8±4.3). We conducted the analysis with a mixed model that included the fixed effects of contemporary groups (ranch, year, time, and sex) and the age covariable of the individual; as random, the direct (D) and maternal (M) genetic effects, plus the covariance between them, (C). By alternating maternal genetic effects, we compared the models: D, DM, and DMC. We selected the models using the likelihood-ratio test. The pedigree was made up of 7498 animals. We estimated the direct (h²) and maternal (m²) heritabilities, as well as the genetic correlations (rg). For the analysis, we used the software MTDFREML. The maternal genetic effects in CH and CP were statistically not different from zero (p±0.05); in the other ZM, the DMC model was the most fit. The h² oscillated between 0.09 (CH) and 0.65 (WH), with an average of 0.40. The m² fluctuated between 0.17 (HSS) and 0.23 (WH), with an average of 0.19. All the rg were negative, between ±0.37 (WH) and ±0.99 (HSS), which must be considered in the genetic improvement of the ZM. [ABSTRACT FROM AUTHOR]

Teak is a commercial tree species of high interest, mainly for its outstanding wood physical and mechanical properties, growth rates and adaptability. The aim of the study was to evaluate the genetic variation of growth and tree quality traits among 40 half-sib families. Using data from a 4-year-old progeny test, narrow sense heritabilities, genetic gains, and genetic correlations were calculated, as well as a ranking of families according to total wood volume per hectare. All the families showed a higher survival rate ranging from 73-100%. The genetic gains by selecting 30% of the best families were of 2.93% for diameter, 4.83% for stem volume, 11.97% for total volume per hectare, 6.53% for crown projection area, 4.26% for branch insertion angle and 14.42% for number of basal sprouts. Three families with superior productivity and potential for the establishment of high yield plantations were identified. [ABSTRACT FROM AUTHOR]

Animal breeding is a predictive science which is carried out on the basis of the genetic variability in the herd and uses selection as an important tool, whose efficiency is assessed by the heritability of the traits of interest, which is a specific parameter of each herd. Due to its good ability to indicate the consequences of the genetic management in production systems, heritability has attracted attention of researchers and received contribution of the evolution of computational resources and statistical methods for the estimation of variance components. This has resulted in higher precision estimates, initially by the Least Squares Method, later by Maximum Likelihood and Bayesian statistics. The Brazilian Nellore herd has undergone these stages in its genetic improvement process, which has been guided by the selection of growth traits (weights at standard ages) as phenotypes of economic interest, which showed moderate to high heritability. Heritability has been estimated by different approaches, but the estimation of variance components by Restricted Maximum Likelihood (REML) has been the favorite. However, limitations such as computational demand and big amount of data have favored the use of Bayesian Inference. Based on these assumptions, the objective of this review is to discuss heritability of growth traits in Nellore cattle, using Maximum Likelihood and Bayesian Inference. [ABSTRACT FROM AUTHOR]

The 30-day weight (P30; 1072) and the weaning (P75; 1750) of 10 flocks were analyzed in Hampshire lambs, to develop two objectives: to evaluate the expression of the genetic effects in the pre-weaning growth, and to analyze the possible implications in the genetic progress. The analyzes were univariate (ANAU) and bivariate (ANAB), through mixed models that included the fixed effects of contemporary groups and the covariable age of the mother; and as random, the direct and maternal genetic effects, the genetic covariance between them and the maternal effects of the permanent environment. Direct herilabilily (h²) and maternal (m²), genetic correlations (rdm), and genetic values (VG) were estimated. With the rank correlations (CR) in the VG, the ranking of the population and of the sire was analyzed; in addition, the genetic trends (TG) of the VGs were analyzed. The h² was in the range of 0.14±0.03 to 0.19±0.04; the m² in ANAU was 0.08±0.04 and 0.02±0.03, with ANAB the estimate was of 0.22±0.05 and 0.13±0.03. The rdm of ANAU was +1±0.15 in P30 and -1±0.18 in PD, changing in the ANAB to -0.46±0.10 and -0.20±0.07, respectively. The behavior of the TG in the ANAU was associated to the magnitude and sign of the rdm; likewise, the rdm of the ANAU implied changes in the ranking of sires, which was reflected in the TG and the CRs. [ABSTRACT FROM AUTHOR]