Search

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]

The expansion of forest plantations to supply the wood market requires selection of genotypes that can provide high gains, which may compromise long-term tree breeding programs. With the final purpose of producing quality sawn wood, the aims of this study were to: (a) estimate genetic parameters for a progeny/provenance test of Plathymenia foliolosa Benth; (b) carry out optimized selection based on an inbreeding rate (F) from 0 to 7% in progeny/provenance tests evaluated at 35 months for P. foliolosa and Cordia trichotoma (Vell.) Arrab. ex Steud, and at 42 months for Zeyheria tuberculosa (Vell.) Bureau ex Verl.; (c) develop a practical index for balancing gains and F; d) and indicate the most appropriate genetic base structure based on effective population size ( N e ) to subsidize conservation strategies, breeding programs, and clonal orchard with those species native from Brazil. Diameters at breast height (DBH) were obtained in progeny/provenance tests conducted in the south of Bahia–Brazil. For P. foliolosa, the moderated heritability (h2a) value of 0.55 demonstrated favorable conditions for selection based on DBH. For this trait, there is better possibility of achieving progressive gains by exploiting genetic variability into the families (CVgi). Simulation of scenarios without optimization for P. foliolosa, C. trichotoma and Z. tuberculosa showed a high possibility of gains for breeding programs, ranging between 95.6 and 311.05%. However, in those scenarios, high rates of F were also observed. For the three species, selection based on the selection optimization index (SOI) was proposed in order to balance ideal increments in genetic gains and maintenance of genetic diversity. With the use of SOI, it was possible to simulate selection of scenarios with good prospects of gain balanced with N e in a practical and direct manner for germplasm conservation strategies, production of improved seeds in clonal orchards, and tracking recombination cycles within breeding populations. [ABSTRACT FROM AUTHOR]

In view of the need to develop new popcorn cultivars and considering the uncertainties in choosing the most appropriate breeding methods to ensure consistent genetic progress, simultaneously for both popping expansion and grain yield, this study addressed the efficiency of interpopulation recurrent selection regarding genetic gains, the study of the response in genetic parameters as well as heterotic effects on the control of the main agronomic traits of popcorn. Two populations were established, Pop1 and Pop2. A total of 324 treatments were evaluated, which consisted of 200 half-sib families (100 from Pop1 and 100 from Pop2), 100 full-sib families from the two populations and 24 controls. The field experiment was arranged in a lattice design with three replications in two environments, in the north and northwest regions of the State of Rio de Janeiro, Brazil. The genotype × environment interaction was partitioned and the genetic parameters, heterosis and predicted gains were estimated by the Mulamba and Mock index, based on selection results in both environments. The genetic parameters detected variability that can be explored in successive interpopulation recurrent selection cycles. Exploring heterosis for GY, PE and yield components is a promising option to increase grain yield and quality. The Mulamba and Mock index was efficient in predicting the genetic gains in GY and PE. Interpopulation recurrent selection proved effective to provide genetic gains for traits with predominantly additive and dominance inheritance. [ABSTRACT FROM AUTHOR]

In fruit tree breeding, selection indices are used to identify the genotypes that combine desirable commercial and non-commercial characteristics. As Theobroma grandiflorum is generally cultivated in agroforestry systems (AFS), there is a need to develop cultivars that are adapted to such environments. In this study, the objective was to select the most promising genotypes for their future use in AFS based on the additive index, a pioneering method for this crop. The trial was carried out for 12 years in an agroforestry system in the municipality of Tomé-Açu, Pará State, Brazil. The 16 evaluated clones were completely randomised with a variable number of repetitions. The average number of fruits produced as well as the morpho-agronomic characteristics of the fruits were analysed. Mixed linear models were used to estimate the components of variance and predict the genotypic values. The genetic correlation between the variables was estimated, and the selection of genotypes was based on the additive index, with a positive orientation of all variables except the thickness of the fruit shells and the weight of the fruits. Clones 42, 44, 46, 47, 57, 61, and 64 performed well for all the analysed variables, resulting in a selection gain of 7.3% and low incidence rates of witches' broom disease. These genotypes can be made available to producers in the form of clones for use in AFS and can further be included in future hybridisations in T. grandiflorum breeding. [ABSTRACT FROM AUTHOR]

Context: Lactation persistency (LP) is an economically important characteristic to include in the selection objectives of the Gyr breed. Two persistency measures were tested to establish their contribution to the genetic evaluation of milk production in this genotype. The second measure of persistency studied would be the more appropriate measure to use in the genetic evaluation of lactation persistency. Aim: The aim of this work was to study LP in Gyr cows by using a random regression model (RRM) in two-trait analysis. Methods: Test-day milk yields (TDMY) of the first two lactations of Gyr cows were analysed. RRM was performed by Bayesian inference using the GIBBS3F90 program. Fourth-order Legendre polynomials were used to describe the random additive genetic and permanent environmental effects of the animal. The fixed effects included in the model were contemporary group and, as covariates, age of cow at calving and the regression function according to the TDMY class of lactation as the average trajectories of lactation curve, distinguished by calving order. Two persistency measures (PS i , i.e. PS1 and PS2) were used in the analyses. Rank correlations were calculated between the predicted breeding values for PS i , 305-day lactation milk yield (MY305), and the regression coefficients a 0 and a 1, to determine the percentage of matching animals between rankings when different selection intensities are applied on the basis of the ranking for MY305. Key results: The heritability estimates for PS1, PS2 and for MY305 were 0.19, 0.12 and 0.41 respectively, in the first lactation, and 0.43, 0.27 and 0.38 in the second lactation. The genetic correlation between MY305 and PS1 was negative and of low magnitude. The rank correlation between breeding values for PS i , obtained for bulls with at least five daughters with production records, was higher than 0.80 in the two lactation periods. Conclusions: The results indicated that PS2 is the more suitable of the two persistency measures used in this work, for inclusion in genetic evaluations of lactation persistency in Brazilian Gyr cows. Implications: PS2 must be included as a selection criteria in a breeding program for the Gyr breed. The Gyr breed has been selected in Brazil for 40 years, mainly for total milk yield. The lactation persistency is closely related to the profitability of a milk production system. More persistent cows need less inputs, they get less sick, have more stayability and behave better reproductively. The results indicated that it is possible to make a selection for lactation persistency and that the second measure considered is better suited to the behavior of milk yield in Gyr breed. [ABSTRACT FROM AUTHOR]

Background: The selection of superior genotypes and adapted to the edaphoclimatic conditions of the region of the introduction produces gains in productivity for forest stands. The objective of this study was to select progenies of Pinus spp. planted in Lavras, Minas Gerais (MG), Brazil. Methods: The experimental site was located on dystrophic Haplic Cambisol. The progeny test was designed as a randomised complete block with 30 replicates and single plot. The treatments corresponded to one progeny of Pinus massoniana, three Pinus caribaea var. bahamensis and 33 Pinus caribaea var. hondurensis arranged with a 3 x 3 m spacing. The traits height (H), diameter at breast height (DBH) and crown projection area (CPA) were measured at 36 months of age. Results: The results showed that heritability in the narrow sense was 0.24 for DBH, 0.27 for H and 0.50 for CPA. The DBH and H traits showed a high-magnitude positive correlation. The P7, P15, P27, P31 and P33 progenies showed better performance than the other progenies for the evaluated traits. Direct and indirect selection showed similar gains, which favors the use of indirect selection; i.e., when selecting progenies for DBH, progenies with better performance in H are also selected. Additionally, DBH may be used at advanced ages given the difficulty of measuring height. The progeny of Pinus caribaea var. hondurensis showed superior performance compared with Pinus caribaea var. bahamensis and Pinus massoniana for the region of Lavras, MG. Conclusions: This study suggests the possibility of expanding the production of Pinus caribaea var. hondurensis in the region of Lavras with progenies P7, P15, P27, P31 and P33, because in the initial assessments they showed greater adaptability to the edaphoclimatic conditions. Nevertheless, performing a future selection with the aim of evaluating resin production is recommended. [ABSTRACT FROM AUTHOR]

The production of passion fruit is important in Brazil. In order to contribute to the development of the most promising cultivars of passion fruit, this study aimed to evaluate the agronomic performance of 32 genotypes of passion fruit in Federal District of Brazil, and to estimate genetic parameters for use in breeding programs. Thirty-two genotypes were used in a randomized block design, with eight plants per plot and four replications. The experiment was conducted in field. Twenty-eight harvests were performed, and the variables analyzed were: productivity estimated, total number of fruits per hectare, average fruit weight and these characteristics following classification of fruits in five categories. The genotypes that presented the highest total yield estimated were MAR20 # 23, AR 01 and PLANTA 7. For industrial purposes, genotypes MAR 20 # 21 and BRS Gigante Amarelo were superior. For fresh consumption, the genotypes with the best performance were PLANT 7, AR 01 and MSC. Total productivity estimated and total number of fruits per hectare in the first-class classification showed high values of heritability and CVg/CVe ratio. These results indicate a favorable condition for selection. [ABSTRACT FROM AUTHOR]

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]

Source of important vitamins, fibers, and minerals, the tomato (Solanum lycopersicum L.) stands out in the world agricultural scenario for its economic and social relevance and versatility. The Brazilian market is dominated by multinationals companies, and this market segment obtains cultivars from other countries, with genetics accurate to climatic conditions and cultivation method very different from those used in Brazil. As a result, the local cultivation of tomatoes plants becomes dependent on market variations and has required a material that has limited production efficiency. This study aimed to estimate genetic parameters from agronomic traits and to select industrial tomato lines using the selection index. A randomized block experimental design with three replications was used. Eightyfive industrial tomato lines from the germplasm bank of the Vivati Plant Breeding Ltda were evaluated. Each plot had 12 plants. The two central plants of each plot were evaluated. The evaluations were carried out using adapted morphological descriptors described in the guidelines for carrying out the distinguishability, homogeneity, and stability (DHE) tests of the Ministry of Agriculture, Livestock, and Supply of Brazil (MAPA). The genotypic determination coefficient (H2) of the traits related to fruit pericarp thickness, fruit firmness, fruit yield, average cycle, average number of fruits per plant, and soluble solids was high. The base index and the classic index presented the largest gain from selection for the fruit yield trait. Rank summation index and genotypeideotype distance index had the highest total selection gain values. The tomato lines PXT601 and PXT610 stood out as superior genotypes by the methods of direct selection and by selection indexes. [ABSTRACT FROM AUTHOR]

The aims of this study were to estimate the genetic parameters for fat-to-protein ratio (F:P) within the first 90 days of lactation and to examine their genetic associations with daily milk yield (MY), somatic cell score (SCS), and calving interval between the first and second calving (IFSC) and between the second and third calving (ISTC) during the first three lactations of Holstein cows. We utilized 200,626 production-related data officially recorded from 77,436 cows milked two or three times a day from 2012 to 2022, sourced from the Holstein Cattle Breeders Association of Paraná State, Brazil. The (co)variance components were estimated using animal models, adopting the restricted maximum likelihood (REML) method with single-trait analysis (for heritability and repeatability) and two-trait analysis (for genetic and phenotypic correlations), per lactation. Regardless of lactation number, heritability estimates were relatively low, ranging from 0.08 ± 0.005 to 0.10 ± 0.003 for F:P; 0.08 ± 0.01 to 0.18 ± 0.005 for MY; 0.04 ± 0.01 to 0.07 ± 0.004 for SCS; and 0.03 ± 0.01 for both IFSC and ISTC. Repeatability estimates within the same lactation were low for F:P (ranging from 0.17 ± 0.002 to 0.19 ± 0.03), high for MY (between 0.50 ± 0.003 and 0.53 ± 0.002), and moderate to high for SCS (between 0.39 ± 0.003 and 0.44 ± 0.004). Genetic correlations between F:P and MY ranged from -0.26 ± 0.03 to -0.15 ± 0.02; F:P and SCS, from -0.06 ± 0.03 to -0.03 ± 0.08; F:P and IFSC, 0.31 ± 0.01; F:P and ISTC, 0.20 ± 0.01; MY and IFSC, 0.24 ± 0.05; and MY and ISTC, 0.13 ± 0.08. The fat-to-protein ratio during early lactation showed low genetic variability, regardless of lactation number. Furthermore, it was genetically correlated with MY, IFSC, and ISTC, although there is an antagonistic and unfavorable correlation between traits that can limit genetic progress., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

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]

This work aimed to estimate the variance components and genetic parameters, the selection gain, and the cause and effect relationships among traits in order to identify important traits for direct and indirect selection of wheat (Triticum aestivum L.) lines. Three strategies were used to obtain selection gains: direct and indirect selection, an index based on "ranks," and the Smith and Hazel index. In the 2017 crop season in Brazil, 420 wheat lines from the F5 generation were conducted in families with intercalary controls. High heritability of spike weight, number of kernels, and total kernel weight resulted in the best direct selection gains. The selection of plants with a high number of tillers resulted in grain yield improvement. The use of selection indexes is important in advanced wheat lines; they promote genetic gains distributed among agronomic traits. [ABSTRACT FROM AUTHOR]

The objective of this study was to estimate the heritability and genetic, phenotypic, and environmental correlations between 305-day milk yield (305MY), age at first calving (AFC), calving interval (CI) and dry period length (DPL), as well as to compare the productive and reproductive performances of several groups of Girolando cows during their first, second and third parturitions in Brazil. Genetic parameters were estimated using uni- and bi-trait analyses via restricted maximum likelihood (REML). Heritability estimates were similar between uni- and bi-trait analyses and varied from 0.20 to 0.28, 0.00 to 0.08 and 0.07 to 0.14 for 305MY, CI and DPL, respectively, whereas AFC was 0.20. Genetic correlations between 305MY and AFC (–0.49) or DPL (–0.40 to –0.79) show a favourable association. However, an unfavourable genetic association was verified between 305MY and CI (0.59) in the first calving. Environmental and phenotypic correlations between 305MY and CI or DPL showed a favourable association (–0.25 to –0.42 and –0.14 to –0.44). Concerning the cow breed group, a decrease in 305MY was observed as the fraction of the Gyr breed increased, whereas animals from the 1/2 Holstein +1/2 Gyr crossbreeding group yielded better performances for AFC and CI. These results reveal large genetic, phenotypic and environmental variations that could be used in selection programmes. [ABSTRACT FROM PUBLISHER]

Genetic parameters were estimated for egg production, egg quality, and eggshell colors in eight lineages of Brazilian laying hens. Age at first egg (AFE), total egg production up to the 45th week (PROD), egg weight (EW), albumen height (AH), yolk color (YC), the Haugh units (HU), eggshell strength (ESS), eggshell thickness (EST), yolk weight (YW), eggshell weight (ESW), and eggshell color (L*, a*, and b*) were measured in 2030 eggs obtained from 645 laying hens. Variance components were estimated from a mixed animal model, which included the fixed effects of contemporary groups, cage location, and hen line, and the additive genetic, permanent environmental, and residual as random effects. In general, heritabilities were low to moderate (h 2 = 0.11 to 0.48). Genetic correlations among eggshell quality traits were moderate to high (0.36 and 0.69). High genetic correlations were obtained between the eggshell color traits [r g = -0.90 (L* and a*); r g = -0.64 (L* and b*); and r g = 0.65 (a* and b*)]. Results suggest that EW is strongly correlated with ESW, but the genetic correlations between EW and ESS and between EW and EST were low. Genetic correlations between L* and eggshell quality traits were low to moderate, suggesting that L* has little or no relation with external egg quality. However, genetic correlations between a* and b* values and eggshell quality traits were high. The genetic correlations between eggshell color and eggshell quality traits were low, suggesting that the eggshell color does not influence external egg quality. Genetic correlations between PROD and egg quality traits were negative and varied between -0.42 and -0.05. This antagonistic relationship emphasizes the importance of adopting breeding schemes that allow the simultaneous genetic progress of these traits by considering their genetic correlation and economic relevance, such as the selection index., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Due to the high milk production of Holstein cows, many countries have chosen to import semen to improve local dairy herds. This strategy would be more effective if this semen was used in the same environment conditions in which the bulls were selected. If the effect of genotype by environment (G × E) interaction is not considered, the estimated breeding values (EBVs) may vary, potentially reducing the selection response. We evaluate the impact of heat stress on selection for milk yield and composition of Holstein cows using random regression models. To verify the interference of heat stress in milk yield (MY) and composition traits (fat, protein, total saturated, and total unsaturated fatty acids content in milk), temperature-humidity index (THI) on test-day milk records was used. The threshold value to divide the environments using test-day information from Brazilian Holstein cows was 72 units of THI, i.e., < 72 represented no heat stress and > 72 represented heat stress. Legendre polynomials of second-order (Leg 2) model and two lactation points (33 and 122 DIM) were used to estimate heritabilities and EBVs for five important dairy traits. The heritabilities of milk components and fatty acids were low (0.09-0.29), regardless of lactation period and degree of heat stress, with the exception of protein content (0.30-0.35). Fat content was the only milk component that was reduced according to the degree of heat stress and lactation period. The EBVs tended to decrease in heat stress conditions, thus animals with high genetic potential demonstrated evidence of G × E interaction. However, acclimatization of dairy cows to heat stress in the farm production systems may have been responsible for the low differences among genetic parameters and EBVs with and without heat stress found in this study., (© 2022. The Author(s) under exclusive licence to International Society of Biometeorology.)

This study aimed to evaluate the resistance of 79 sugarcane genotypes (varieties and elite clones) artificially inoculated with a severe Sugarcane mosaic virus (SCMV) strain and to estimate genetic parameters associated with SCMV resistance. Symptoms were evaluated using a graded scale, and confirmation of infection was performed using the Plate Trapped Antibody -ELISA serological test in plants conducted in a greenhouse experiment and then validated under field conditions. The mean incidence of mosaic disease was low in greenhouse conditions, with higher observed incidence values when assessed in the field. Based on the field results, variance analysis was significant for genotypes and genotype × environment interaction. Tracking mosaic symptom expression over time in the different sugarcane genotypes revealed varying behavior, including recovery from disease in some genotypes. The broad-sense heritability based on the mean and individual level was 62.18% and 19.37%, respectively. Twenty-two genotypes were observed to be resistant to SCMV. [ABSTRACT FROM AUTHOR]

• Thermal stress during late gestation impairs the future performance of the calf. • Thermal stress provides background for genotype by environment interaction. • Thermal stress can alter the ranking of breeding values of animals. Heat stress suffered by pregnant cows can impair fetal development and have negative consequences for the future performance of calves. Thus, our objective was to determine the effect of heat stress during late gestation on birth weight (BW) and postnatal growth traits of Hereford-Braford and Angus-Brangus cattle from Brazil. In addition, we employ a reaction norm model to investigate the genotype by environment interaction (G × E) due to thermal stress in late gestation. The average temperature and humidity index of the last 60 days of gestation (THIg) was chosen as an environmental descriptor. The BW of animals was considerably lower for extreme low and high values of THIg. In contrast, the average daily gain from birth to weaning (ADG) and muscling score at weaning (MUS) were gradually reduced by increasing THIg values by -0.0014 kg /day/THIg -0.0119 units/THIg, respectively. The variation observed for the estimates of variances, direct and maternal heritability for BW, ADG, and MUS suggest that there is substantial heterogeneity of genetic variances along the environmental gradient. Thus, differences in response to selection are expected depending on the level of thermal stress where selection candidates are evaluated. Genetic correlation estimates for direct and maternal effects between distant THIg values differed from unity or were negative for all traits. This was another strong indication that few of the same genes are responsible for the same trait in contrasting thermal environments during late pregnancy. In this sense, the thermal environment during late gestation provides background for G × E and should be appropriately considered in genetic evaluations of Hereford-Braford and Angus-Brangus cattle reared on pasture in (sub)tropical regions. [ABSTRACT FROM AUTHOR]

• Flower length presented the highest heritability and its strongly correlated with fruit dimensions. • Five harvests are an adequate number for the selection of superior genotypes. • Genotypes 25, 10 and 47 (green fruits), and 11 (red fruits) are candidates for new cultivars. • Simultaneous selection was shown to be an important tool for genetic improvement. There are limited number of studies on the genetic improvement of sugar apple (Annona squamosa L.), in addition to this there are few studies available on the in situ and ex situ characterization and conservation of its germplasm, this has restricted the advancement of the cultivation of its fruit in Brazil. The present study aims to estimate the genetic parameters, establish Pearson's correlations between agronomic traits, and predict the genetic gains in half-sib progenies of sugar apple for selection purposes. The experiment included four half-sib progenies of sugar apple (UNI-1, UNI-2, UNI-3, and UNI-4) distributed in a random-block experimental design with three repetitions and five plants per plot. Field evaluation using eight quantitative traits were assessed over eight harvests during the fourth, fifth, sixth, and seventh years of production. Flower length had a high heritability (66%). There was a positive Pearson correlation between total yield and number of fruits per plant, and flower length was strongly correlated with traits related to fruit size. Flower number, flower length, fresh fruit mass, fruit diameter and fruit length also showed high repeatability. It was observed that five harvests are an adequate number for the selection of superior genotypes, and that these evaluations should be carried out between the fourth and sixth year after planting. The Mulamba and Mock 2 index (MM2) was used as criterion for simultaneous selection of genotypes. Genotypes 25 (UNI-1), 10 and 47 (UNI-2), and 11 (UNI-3) stood out for achieving high scores in more than one trait. They should be considered for selection as they allow the best offspring to be selected, are potential candidates for new cultivars and will be prioritized for the next recombination cycle of the breeding program. [ABSTRACT FROM AUTHOR]

The objective of the present study was to estimate genetic parameters for growth and reproductive traits of Morada Nova sheep reared by smallholder farmers in the semi-arid northeastern region of Brazil. Data from 11 participating flocks, between 2007 and 2011, were used for the estimation of (co)variance components and genetic parameters for birth weight (BW), weight at weaning adjusted for 112 days of age (WW), average daily weight gain from birth to weaning (ADG), days to lambing (DL), lambing interval (LI), total litter weight at birth (LWB), total litter weight at weaning (LWW) and the ratio between total litter weight at birth and weaning and metabolic weight of the dam (LWB/MW and LWW/MW, respectively). The direct heritabilities obtained by one-trait analysis were 0.19, 0.14, 0.11, 0.13, 0.0, 0.44, 0.19, 0.41, 0.15, respectively for BW, WW, ADG, DL, LI, LWB, LWW, LWB/MW and LWW/MW. The direct heritabilities for BW and WW obtained by two-trait analysis were similar to those estimated by one-trait analysis. However, the direct heritabilities for LWB, LWW and LWW/MW obtained by two-trait analysis were higher than those estimated by one-trait analysis. The genetic correlation between BW and WW were 0.75 and between LWB, LWW and LWW/MW were 0.8, 0.9 and 1.0, respectively. In conclusion, except for LI, there is genetic variability that can be explored by direct and indirect selection to obtain genetic gains in the flocks participating in the Nucleus of Participatory Breeding of Morada Nova Sheep. [ABSTRACT FROM AUTHOR]

Highlights: [•] Eucalypt productivity is related to the interaction among the environment, genotype, management, pest and diseases. [•] The selection for eucalypt rust resistance in climatic conditions showed a simple genotype-environmental interaction. [•] There is good relationship between rust severity and theoretical model with annual average temperature and leaf wetness. [•] Heritability among the progenies was high, indicating improvement through progenies selection. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Saúde e Produção Animal (RBSPA) is the property of Revista Brasileira de Saude e Producao Animal (RBSPA) 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.)

Abstract: The objective of this paper is to model variations in test-day milk yields of first lactations of Holstein cows by RR using B-spline functions and Bayesian inference in order to fit adequate and parsimonious models for the estimation of genetic parameters. They used 152,145 test day milk yield records from 7317 first lactations of Holstein cows. The model established in this study was additive, permanent environmental and residual random effects. In addition, contemporary group and linear and quadratic effects of the age of cow at calving were included as fixed effects. Authors modeled the average lactation curve of the population with a fourth-order orthogonal Legendre polynomial. They concluded that a cubic B-spline with seven random regression coefficients for both the additive genetic and permanent environment effects was to be the best according to residual mean square and residual variance estimates. Moreover they urged a lower order model (quadratic B-spline with seven random regression coefficients for both random effects) could be adopted because it yielded practically the same genetic parameter estimates with parsimony. [Copyright &y& Elsevier]

The objectives of this study were to identify promising popcorn lines and hybrids for genetic resistance to tropical rust (Tr, Physopella zeae) in diallel crosses of nine lines derived from a large part of Brazilian popcorn germplasm and to estimate genetic parameters for Tr resistance. Crosses and checks were tested in a random block design, with artificial inoculations under greenhouse conditions. Plots consisted of a single 14-L pot, with four plants. Tr was measured by severity and area under the disease progress curve. Data was analyzed by Griffing's diallel model, and genetic parameters were estimated. Heritability estimates to Tr resistance was medium. Specific combining ability-SCA had significant effects (P<0.10) for resistance, and was eight to nine times larger than general combining ability-GCA (P>0.10). This indicated the major importance of non additive gene effects. In general, breeding possibilities for resistance was restricted. The line 9 (L7.4) had the most outstanding GCA for resistance to Tr, and hybrids 1×7 and 3×6 had outstanding SCA and were recommended for breeding. [ABSTRACT FROM AUTHOR]

In this study, Bayesian analysis under a threshold animal model was used to estimate genetic correlations between morphological traits (body structure, finishing precocity and muscling) in Nelore cattle evaluated at weaning and yearling. Visual scores obtained from 7651 Nelore cattle at weaning and from 4155 animals at yearling, belonging to the Brazilian Nelore Program, were used. Genetic parameters for the morphological traits were estimated by two-trait Bayesian analysis under a threshold animal model. The genetic correlations between the morphological traits evaluated at two ages of the animal (weaning and yearling) were positive and high for body structure (0.91), finishing precocity (0.96) and muscling (0.94). These results indicate that the traits are mainly determined by the same set of genes of additive action and that direct selection at weaning will also result in genetic progress for the same traits at yearling. Thus, selection of the best genotypes during only one phase of life of the animal is suggested. However, genetic differences between morphological traits were better detected during the growth phase to yearling. Direct selection for body structure, finishing precocity and muscling at only one age, preferentially at yearling, is recommended as genetic differences between traits can be detected at this age. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the variability and the genetic correlations between clones RB and the varieties of cane sugar. The experimental works were carried out during the 2005/2006 agricultural year in Central Olho D'Água Sugar Mill (North Forest of Pernambuco, Brazil) and Trapiche (South Coast of Pernambuco, Brazil). The experimental design was made in randomized blocks with four blocks and different treatments, one with sixteen genotypes conducted in North Forest, and another with eighteen other genotypes installed on the South Coast. The following characters were defined as production components: average culms number, average culms diameter, average culms weight, average internodes number, average culms height and average leaf area. Results indicated that the genetic variability in genotypes populations and the commercial varieties tested in the North Forest and South Coast of Pernambuco, can be effective in selecting genotypes through leaf area, and culms height and weight; determining characteristics of the production of sugarcane. The number of culms is negatively associated with culms diameter, height and weight, the number of internodes and the leaf area, thus preventing the simultaneous or indirect selection between the characters pairs. [ABSTRACT FROM AUTHOR]

The objective was to assess the genetic potential of maize population UFV 7 for breeding in Minas Gerais, Brazil. Three experiments were installed with the maize population UFV 7 in the three regions of Minas Gerais, in the harvest of 2006/2007. There was genotype x environment interaction for all characters. It was observed genetic variability for grain yield, plant height and ear height in maize population UFV 7, in the three regions. The Southeast region was where the maize population UFV 7 had the highest parameters. The population UFV 7 presented high grain yield, 9 112kg ha-1 in the Southeast, average grain yield, 6 510kg ha-1 in the West and low, 4 572kg ha-1 in the Central Region. Heritability estimate and CVg / CVe for grain yield were higher than 60% and 1.00, respectively. Grain yield had significant and positive genetic correlation with plant height and ear height, in Western and Central, and the prolificacy in Central and Southeast. For maize population UFV 7 it was conclude that it has potential for extraction of lines in the Central Region; it has the potential for immediate use in the Southeast and for new cycles selection in the Western Region of Minas Gerais. The selection for PG provides an indirect increase in plant height and ear height, in the West and Central. [ABSTRACT FROM AUTHOR]

New statistical models for genetic parameters estimation based on longitudinal data have been proposed. In this study, we considered the data of 47,614 test-day milk yields from 1,578 buffaloes, with 4,757 complete lactations, calving from 1985 to 2006. Single-, two- and multiple trait analyses were used and variance components were estimated by Restricted Maximum Likelihood. The model used to evaluate the milk yield trait at 305 days (MY305) included: i) herd-year-calving season (contemporary group) and milking number as fixed effects; ii) buffalo age at calving as covariate (linear and quadratic effect); iii) additive genetic, permanent environmental, residual and the animal as random effects. The same effects were included in the test-day milk yield model except the contemporary group, defined as herd-year-test day. The heritability estimations for TDMY vary from 0.13 to 0.23 for single-trait analyses, from 0.13 to 0.24 for two-trait analyses and from 0.15 to 0.24 for the multiple-trait analyses. The results obtained for each of the three models showed that the higher heritability estimations were always obtained in the third test month. The genetic correlations between the TDMY and MY305 were high and positive. In conclusion, the TDMY trait use into the selective process will promote genetic changes similar to the ones obtained through the MY305. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate seventeen lineages and three cultivars of cowpea [Vigna unguiculata (L.) Walp.] with semi-prostrate port, in relation to grain yield and components related to the cycle and the plant architecture under dry and irrigated cultivation, in Teresina County, Piauí State, Brazil. Two experiments were conducted with a completely randomized desing with twenty treatments and four repetitions. The MNC99-541F-15, TE96290-12G, MNC99-547F-2, MNC99-510F-16 and TE97-304G-12 lineages and BRS-Marataoã and BR-17 Gurguéia cultivars showed the largest yields under dry cultivation. From another standpoint, the MNC99-542F-5, TE96-290-12G, TE97-304G-12, MNC99-541F-18, TE97-309G-24, MNC99510F-16, TE97-304G-4, MNC99-547F-2, MNC99-510F-16 lineages and the BRS Paraguaçu cultivar stood out in the irrigated cultivation. The lineages TE96-290-12G, MNC99-510F-16 and TE97-304G-4 showed good yields levels in both cultivation systems. These results, besides the identification of genotypes with the largest productive potential, suggest that it is possible to select genotypes to dry and irrigated cultivation. [ABSTRACT FROM AUTHOR]

Abstract: A total of 152,145 weekly test-day milk yield records from 7317 first lactations of Holstein cows distributed in 93 herds in southeastern Brazil were analyzed. Test-day milk yields were classified into 44 weekly classes of DIM. The contemporary groups were defined as herd-year-week of test-day. The model included direct additive genetic, permanent environmental and residual effects as random and fixed effects of contemporary group and age of cow at calving as covariable, linear and quadratic effects. Mean trends were modeled by a cubic regression on orthogonal polynomials of DIM. Additive genetic and permanent environmental random effects were estimated by random regression on orthogonal Legendre polynomials. Residual variances were modeled using third to seventh-order variance functions or a step function with 1, 6, 13, 17 and 44 variance classes. Results from Akaike''s and Schwarz''s Bayesian information criterion suggested that a model considering a 7th-order Legendre polynomial for additive effect, a 12th-order polynomial for permanent environment effect and a step function with 6 classes for residual variances, fitted best. However, a parsimonious model, with a 6th-order Legendre polynomial for additive effects and a 7th-order polynomial for permanent environmental effects, yielded very similar genetic parameter estimates. [Copyright &y& Elsevier]

Abstract: A total of 306,698 racing performance data recorded between 1992 and 2002 from 25495 Brazilian Thoroughbred horses was analyzed to estimate the variance components using the Random Regression Model (RRM) compared to the Classical Repeatability Animal Model (CRAM). The performance was evaluated using the race time (in seconds) to run distances of 1000, 1100, 1200, 1300, 1400, 1500 or 1600 meters. The pedigree of each horse was extended as far as possible, with a total of 36,659 animals. The simple correlation between Breeding Value (BV) for the race time estimated by both procedures was high (r=0.963) when the data were expressed at the mean level of all distances. However, with the RRM it was possible to estimate the genetic parameters and the BV of all animals at the trajectory of each one of the seven distances. Also, results clearly showed that a single BV estimated by CRAM, is neither an adequate nor a sufficient indicator for the selection of the best horses throughout the trajectory of distance performance. We concluded that the RRM procedure is highly recommended for the evaluation of racehorse performance. [Copyright &y& Elsevier]

Abstract: This paper deals with the effects of hair coat characteristics on the sweating rate of Brazilian Braford cows and estimation of heritabilities and genetic correlations of these traits. Data (n =1607) on hair length, coat thickness, hair diameter, number of hairs per unit area, coat reflectance and sweating rate were recorded from heifers and cows of a commercial herd managed on range under extensive system. The data were analyzed considering the following effects on the model for hair coat traits: classes of sires and contemporary groups; linear effects of month and genotype; linear and quadratic effects of age. The effect of sire was important (P <0.05) for all hair coat traits, except for number of hairs; contemporary groups affected (P <0.05) all hair coat traits; the effect of sampling month was important (P <0.05) for hair length and reflectance; genotype affected (P <0.05) hair length, diameter and coat reflectance; the quadratic effect of age was important (P <0.05) only for coat reflectance. Two models were used to analyze the sweating rate. The first model considered the following fixed effects: classes of contemporary groups and sires; linear effect of genotype, coat thickness, hair length, hair diameter, number of hairs, coat reflectance; linear and quadratic effects of time of day, age, air temperature, partial vapour pressure and radiant heat load. The second model used for the sweating rate considered the same fixed effects for the first model, except that the hair coat characteristics were adjusted for important effects used in the models to analyze hair coat traits. All meteorological factors and contemporary groups were important (P <0.05) on variation of sweating rate in both models. The Restricted Maximum Likelihood (REML) method was used to estimate variance and covariance components under the sire model. Results included heritability estimates in narrow (h 2 ) and broad (H 2) sense for single-trait analyzes: hair thickness (h 2 =0.16; H 2 =0.26); hair length (h 2 =0.18; H 2 =0.39); number of hairs (h 2 =0.08±0.07; H 2 =0.08±0.07); hair diameter (h 2 =0.12±0.07; H 2 =0.12±0.07); coat reflectance (h 2 =0.30; H 2 =0.42); and sweating rate (h 2 =0.10±0.07; H 2 =0.10±0.07). In general, the genetic correlations between the adaptive traits were favorable as for the direction to select for adaptation in tropical environment; however, they presented high standard errors. The results of this study imply that hair coat characteristics and sweating ability are important for the adaptability to heat stress and they must be better studied and further considered for selection for genetic progress of adaptation in tropical environment. [Copyright &y& Elsevier]

• Heritabilities for growth increase with age for most A. angustifolia provenances. • Greater genetic variation for growth is found within than between provenances. • Early selection at age 7–10 provides 85% prediction accuracy of growth at age 35. • Individual and family selection could reduce harvest age to 15–20 years. • More investments in breeding and plantation forestry of A. angustifolia are timely. Understanding the growth patterns of long-lived conifer tree species is important to devise breeding and early selection strategies, predict future biomass productivity and assess adaptive tree fitness for long term conservation efforts. We investigated the genetic variation for growth traits of Araucaria angustifolia, the grandiose renowned "Paraná pine" tree, in a trial involving 122 families across 15 provenances covering the entire natural range of the species in Brazil. Measurements at ages 7, 24, 32, 33 and 35 were used to adjust continuous growth curves based on nonlinear mixed-effect models for all 2158 trees, providing annual estimates for unmeasured ages in the 7-to-35-year interval. Estimated values closely matched observed ones and a reduction of the coefficient of residual variation was observed in the estimated data, possibly due to removal of random error in the observed measurements, making the estimated curves more reliable to predict growth patterns. Genetic variation for growth within provenances was greater than between, with a trend of increasing heritabilities over time for most provenances. Substantial genetic variation found both within and between families could drive efficient early selection at both levels. All provenances included individual trees and families with good potential to be selected for shorter rotations. Growth curves show that trees invest first in height and later in diameter growth. Considerable variation was observed across provenances for the optimal age and optimal tree volume at which annual growth increment peaks, a tipping point that could be used as a predictor of the optimal rotation age and expected tree volume. The data clearly indicate potential for early selection for growth at age 7–10 with an 85% prediction accuracy of growth at age 35. Additionally, growth data indicate potential of shortening harvest age from 30–35 to 15–20 years by selecting the best individuals and families. These results underscore the potential of expanding investments in breeding and plantation forestry of A. angustifolia, which in parallel could contribute to enhancing conservation efforts of this iconic subtropical conifer. [ABSTRACT FROM AUTHOR]

• Worms and ticks cause considerable economic and productive losses in beef cattle. • The choice of statistical model can impact genetic analysis of parasite infestation. • Heritability estimates were low to moderate for both worm and tick infestation. • A better fit was observed for models employing non-Gaussian distributions. • Genetic selection and parasite control practices should be carried out together. Worms and ticks are important parasites in beef cattle, especially in tropical areas, causing significant economic and production losses. Understanding animal-to-animal variation on infestation for these parasites might guide genetic selection and improvement of management practices to attenuate its detrimental effects. Statistical models used to analyze such traits usually assume a Gaussian distribution for the observed data. However, this assumption is quite often inappropriate for counting data. Therefore, the objectives of this study were: 1) Estimate genetic parameters for worms and tick infestations in Nellore cattle, and 2) To compare the overall performance of six data analysis approaches for worm and tick infestation in Nellore cattle, using different specifications of generalized linear mixed models (GLMM) and response variables. Data consisted of presence/absence of parasites as well as counting observations for both worms and ticks in a Nellore herd in Brazil. The binary data were analysed with both Gaussian and Threshold models, whereas the counting data were studied using Gaussian models on the original and logarithmic scales, as well as Poisson and Zero-Inflated Poisson (ZIP) models. All models included the systematic effects of contemporary group and age, as well as the random additive genetic and residual effects. Models were compared using four criteria: Deviance Information Criterion (DIC), Spearman's correlation between predicted breeding values from different models, the agreement on the 5 and 50% top-ranked animals across models, and the Mean Squared Error of Prediction (MSEP) assessed via Monte Carlo Cross-Validation (MCCV). The MCCV was performed using parallel computing through the Center for High Throughput Computing (CHTC) at the University of Wisconsin-Madison. The estimates of heritability ranged from 0.15 to 0.40 for worms and from 0.08 to 0.25 for ticks. According to the DIC, non-Gaussian models displayed the best goodness of fit compared to Gaussian models. DIC's results excluded Gaussian models on the logarithmic scale because fairer comparisons involve phenotypes on the same scale. Spearman's correlation and the percentage of agreement on the 5% and 50% top-ranked animals suggested some re-ranking of animals depending upon the model used. Monte Carlos Cross-Validation showed that all models presented similar MSEP with average values of 0.20 (binary data; worms), 0.18 (binary data; ticks), 15.69 (count data; worms), and 14.19 (count data; ticks). Moreover, performing MCCV in parallel had the benefit to deliver results for all models in about 2 days. Heritability estimates indicate that the selection of high merit animals for worms and tick infestation is possible feasible and can potentially contribute to the genetic progress. Furthermore, genetic selection should be performed concomitantly with traditional parasite control approaches. Overall, non-Gaussian models seem to be better suitable for genetic analysis of worm and tick infestation in beef cattle, because such models have lower DIC values with similar predictive performance compared to Gaussian models. [ABSTRACT FROM AUTHOR]

• Initial breeding programs for solid wood production show promising results. • Genotype-by-environment interaction affects Corymbia citriodora survival. • Corymbia citriodora present genotypes adapted to different soil textures. • Low additive genetic variance can limit the development of breeding populations. Corymbia citriodora is one of the most cultivated hardwood species by small farmers in Brazil, and the most traded wood on the east coast of Australia due its high growth rate combined with high wood density. The study of genotype-by-environment interaction (GEI) is one of the most critical elements in the management of a breeding program to define breeding zones and to select genetic material targeted to specific environmental conditions. The aim of this research was to estimate genetic parameters in a C. citriodora progeny tests, established using 56 open-pollinated families in three sites with contrasting soil texture within the Luiz Antônio's experimental station, Brazil. The following traits were measured at 30 years of age: total height, diameter at breast height (DBH), stem form and survival. Based on this data, the individual volume was estimated. The harmonic mean relative performance of genetic values (MHPRVG) predicted by BLUP was used to evaluate productivity, stability and adaptability. The GEI was found to be not significant in all growth traits. A complex GEI was detected only for survival, supporting the importance of choosing the right genetic material of the species to specific sites. The present analysis showed a significant difference between families for DBH, survival and volume. In summary, the material studied presents potential to obtain attractive genetic gains through selection. However, in order to keep these sustained gains over the next selection cycles it is necessary to incorporate new genetic materials in order to increase genetic diversity. [ABSTRACT FROM AUTHOR]

The present study estimated genetic parameters and evaluated the genetic and phenotypic correlations between meat quality characteristics of Nellore cattle evaluated at different anatomical points of the longissimus. Data from 1329 Nellore young bulls were used to evaluate, in the 5th and 12th ribs, marbling score (MAR), shear force (SF), cooking weight losses (CWL) and intramuscular fat (IMF). In addition, the subcutaneous fat thickness was measured at the 12th rib (SFT 12 ) and between the last lumbar and the first sacral vertebrae (SFT LR ), in the separation of loin and round. Results yielded moderate heritability coefficients for evaluated characteristics, except CWL. High genetic correlations (0.61) were found between measurements of SFT 12 and SFT LR . MAR, IMF and SF were evaluated at the 5th and 12th rib. Meat quality and subcutaneous fat thickness measured at different anatomical points of the longissimus are genetically correlated and can be used in genetic selection programs to improve meat quality characteristics in Nellore cattle., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Remarkable increases in the production of dairy animals have negatively impacted their tolerance to heat stress (HS). The evaluation of the effect of HS on milk yield is based on the direct impact of HS on performance. However, in practical terms, HS also exerts its influence during gestation (indirect effect). The main purpose of this study was to identify and characterize the genotype by environment interaction (G × E) due to HS during the last 60 days of gestation (THI&#95;g) and also the HS postpartum (THI&#95;m) over first lactation milk production of Brazilian Holstein cattle. A total of 389 127 test day milk yield (TD) records from 1572 first lactation Holstein cows born in Brazil (daughters of 1248 dams and 70 sires) and the corresponding temperature-humidity index (THI) obtained between December 2007 and January 2013 were analyzed using different random regression models. Cows in the cold environment (THI&#95;g = 64 to 73) during the last 60 days of gestation produced more milk than those cows in a hot environment (THI&#95;g = 74 to 84), particularly during the first 150 days of lactation (DIM). The heritabilities (h2) of TD were similar throughout DIM for cows in THI&#95;g hot (0.11 to 0.20) or (0.10 to 0.22), while the genetic correlations (rg) for TD between these two environments ranged from 0.11 to 0.52 along the first 250 DIM. The h2 estimates for TD across THI&#95;m were similar for cows in THI&#95;g hot (0.07 to 0.25) and THI&#95;g cold (0.08 to 0.19). The rg estimates ranged from 0.17 to 0.42 along THI&#95;m between TD of cows in cold and hot THI&#95;g. The results were consistent in demonstrating the existence of an additional source of G × E for TD due to THI&#95;g and THI&#95;m. The present study is probably the first to provide evidence of this source of G × E; further research is needed because of its importance when the breeding objective is to select animals that are more tolerant to HS.

Provenance and within-provenance genetic variation for stem volume growth in Eucalyptus urophylla was examined in a large trial series of 125 provenance/progeny tests in five countries. In general, heritability (within-provenance) for age-3 volume was around 0.15 for Brazil, Colombia, Mexico, and South Africa and was slightly lower in Venezuela, where tree volume was lower. Provenances from all seven islands in Indonesia where the species occurs were included in the trials. Substantial provenance variation was observed in all countries, with the best provenances showing from 25 to 30 % more volume than the mean. The average of between-country genetic correlation estimates for growth traits was 0.72, both among and within provenances. Provenance and family performance between Mexico and Venezuela were very similar, with estimated provenance and within-provenance genetic correlations of 1.00 and 0.90, respectively. There was some tendency for lower-elevation provenances to show better volume growth, but there were also very large differences observed between provenances located very close to one another. The results underscore the value of extensive provenance collections throughout the range of a species in order to ensure that the very best provenances are being captured. [ABSTRACT FROM AUTHOR]