Use of Physiological Parameters in Screening Drought Tolerance in Sugarcane Genotypes

The physiological response of four commercial sugarcane genotypes to water stress was evaluated by measuring the photochemical efficiency of the photosystem II (chlorophyll a fluorescence ratio, F v/F m), estimated chlorophyll content (SPAD unit), leaf temperature (LT) and leaf relative water content (RWC). A field trial was established in the subtropical area with well-watered and water-stressed genotypes, in completely randomized blocks with four replicates in a 4 × 2 × 3 factorial design (genotype × irrigation × evaluation date). Physiological measurements were done during a 90 day-period of formative stage of plants. The analysis of variance showed that the interaction of genotype × irrigation × evaluation date had a significant effect for three physiological markers tested, F v/F m, SPAD unit and RWC. Under non-stressed conditions, all genotypes showed similar responses for the four markers. Under water deficiency stress, two drought-tolerant genotypes, HOCP01-523 and TCP89-3505 displayed higher values for F v/F m, SPAD unit and RWC, and lower values for LT, and could be classified as tolerant. It is therefore possible to use these physiological water stress associated traits as scorable marker traits for selecting drought-tolerant sugarcane genotypes in future breeding programs. © 2011 Society for Sugar Research & Promotion.

Genetic parameters for test-day milk yield, 305-day milk yield, and lactation length in Guzerat cows

Milk production in tropical environments requires the use of crossbreeding systems including breeds well adapted to harsh conditions, but with lower productivities when compared to specialized breeds. Besides the genetic improvement for milk production, lactation lengths also need to be studied for most of these breeds. Accordingly, genetic parameters were estimated for 305-day cumulative milk yield (MY305), test-day milk yield (TDMY), and lactation length (LL) using information from the first lactations of 2816 Guzerat cows selected for milk production in 28 herds in Brazil. Contemporary groups were defined as herd, year and season of the test for TDMY, and as herd, year and season of calving for MY305 and LL. Variance components were estimated with the restricted maximum likelihood method under a multi-trait animal model. Heritabilities estimated for TDMY ranged from 0.16 to 0.24, and were 0.24 and 0.12 for MY305 and LL, respectively. Genetic correlations were high and positive, ranging from 0.51 to 0.99 among TDMY records, from 0.81 to 0.98 between each TDMY and MY305, and from 0.71 to 0.94 between each TDMY and LL. Genetic parameters obtained in this study indicated the possibility of using test-day records for the prediction of breeding values for milk yield in this population of the Guzerat breed. The use of TDMY as selection criteria would result in indirect gains in MY305 and LL. However, the highest response to selection for MY305 would be obtained by direct selection for this trait. © 2012 Elsevier B.V.

Genetic parameters for milk yield, lactation length and calving intervals of murrah buffaloes from brazil

The major objective of this study was to estimate heritability and genetic correlations between milk yield (MY) and calving interval (CI) and lactation length (LL) in Murrah buffaloes using Bayesian inference. The database used belongs to the genetic improvement program of four buffalo herds from Brazil. To obtain the estimates of variance and covariance, bivariate analyses were performed with the Gibbs sampler, using the program MTGSAM. The heritability coefficient estimates were 0.28, 0.03 and 0.15 for MY, CI and LL, respectively. The genetic correlations between MY and LL was moderate (0.48). However, the genetic correlation between MY and CI showed large HPD regions (highest posterior density interval). Milk yield was the only trait with clear potential for genetic improvement by direct mass selection. The genetic correlation between MY and LL indicates that indirect selection using milk yield is a potentially beneficialstrategy.Theinterpretation of the estimated genetic correlation between MY and CI is difficult and could be spurious. ©2013 Sociedade Brasileira de Zootecnia.

Multiple-trait random regression models for the estimation of genetic parameters for milk, fat, and protein yield in buffaloes

In this study, genetic parameters for test-day milk, fat, and protein yield were estimated for the first lactation. The data analyzed consisted of 1,433 first lactations of Murrah buffaloes, daughters of 113 sires from 12 herds in the state of São Paulo, Brazil, with calvings from 1985 to 2007. Ten-month classes of lactation days were considered for the test-day yields. The (co)variance components for the 3 traits were estimated using the regression analyses by Bayesian inference applying an animal model by Gibbs sampling. The contemporary groups were defined as herd-year-month of the test day. In the model, the random effects were additive genetic, permanent environment, and residual. The fixed effects were contemporary group and number of milkings (1 or 2), the linear and quadratic effects of the covariable age of the buffalo at calving, as well as the mean lactation curve of the population, which was modeled by orthogonal Legendre polynomials of fourth order. The random effects for the traits studied were modeled by Legendre polynomials of third and fourth order for additive genetic and permanent environment, respectively, the residual variances were modeled considering 4 residual classes. The heritability estimates for the traits were moderate (from 0.21-0.38), with higher estimates in the intermediate lactation phase. The genetic correlation estimates within and among the traits varied from 0.05 to 0.99. The results indicate that the selection for any trait test day will result in an indirect genetic gain for milk, fat, and protein yield in all periods of the lactation curve. The accuracy associated with estimated breeding values obtained using multi-trait random regression was slightly higher (around 8%) compared with single-trait random regression. This difference may be because to the greater amount of information available per animal. © 2013 American Dairy Science Association.

Genetic parameters for scrotal circumference, breeding soundness examination and sperm defects in young Nellore bulls

A total of 51,161 records of scrotal circumference measurements at 18 mo of age (SCI 8) and 17,648 records of sperm defects and breeding soundness of Nellore bulls (mean age of 22.5 mo), raised under extensive conditions, were analyzed to estimate coefficients of heritability and genetic correlations of morphological semen traits by Bayesian inference. The observed semen traits were classified as minor (MID). major (MAD), and total sperm defects (TD). The animals were classified according to breeding soundness as satisfactory and unsatisfactory potential breeders. The (co)variance components and breeding values were estimated by Gibbs sampling using the GIBBS2F90 program under an animal model that included contemporary group as fixed effect, age of animal as linear covariate, and direct additive genetic effects as random effects. Heritabilities of 0.40 ± 0.02, 0.16 ± 0.02, 0.04 ± 0.01, 0.15 ± 0.01, and 0.10 ± 0.01 were obtained for SCI8, MID, MAD, TD, and breeding soundness, respectively. The SC18 showed a positive and moderate correlation with breeding soundness (0.56 ± 0.04) and a negative and low correlation with MID (-0.23 ± 0.03), MAD (-0.16 ± 0.02), and TD (-0.24 ± 0.02). In conclusion, scrotal circumference showed the best response to selection among the traits studied and was favorably correlated with breeding soundness and sperm morphology in young Nellore bulls. © 2013 American Society of Animal Science. All rights reserved.

Inversion method for obtaining electrical parameters for soil in the rural region in Brazil

This paper presents an inversion methodology through weighted least squares to obtain the electrical parameters for the soil of a typical mid-western region in Brazil using the model based in the formalism of the parabolic equations to calculate the electric field intensity received. To validate this methodology, the results of the radio signal measurement campaign conducted in six radial routes leaving the city of Brasilia, Federal District, where the transmitter was located, were used. The measurements were compared to computer simulations and, thus, the optimal values for the electric conductivity and relative permittivity for the soil of the region could be estimated. Finally, a quantitative analysis of these parameters was performed with the values found in the literature, which demonstrated the effectiveness of the proposed methodology.

Population Parameters Based on Known Pedigree Records from Brazilian Jaffarabadi Buffaloes

The objective of this study was to evaluate the effective number of founders and ancestors, generation intervals and completeness of pedigree in Jaffarabadi breed buffaloes raised in Brazil. Pedigree records of 1,272 animals born from 1966 were used. The parameters were estimated using ENDOG, computational population genetic software. The obtained value for completeness of pedigree was 99.5, 50.9, and 20.5 for, the first, second and third generations, respectively. Generation interval estimates expressed in years and considering different pathways were 12.28 +/- 6.90 (sire-son), 11.55 +/- 6.07 (sire-daughter), 8.20 +/- 2.63 (dam-son) and 8.794 +/-.33 (dam-daughter). The overall average generation interval was 10.17 +/- 5.43 years. The number of founders, equivalent founders and ancestor animals that contributed for the genetic diversity in the reference population (1059) were 136, 130 and 134, respectively. Effective number of founder (f(e)=8) and ancestors (f(a)=7) were small, and the calculated expected inbreeding increase per generation was 4.99%. Four ancestors explained 50% of the genetic variability in the population and the major ancestor contributed with approximately 33% of the total population genetic variation. The genetic diversity within the current population is low as a consequence of a reduced number of ancestors.

Genetic Parameters for Productive and Reproductive Traits for Milk Buffalo in Brazil

Knowing the genetic parameters of productive and reproductive traits in milking buffaloes is essential for planning and implementing of a program genetic selection. In Brazil, this information is still scarce. The objective of this study was to verify the existence of genetic variability in milk yield of buffaloes and their constituents, and reproductive traits for the possibility of application of the selection. A total of 9,318 lactations records from 3,061 cows were used to estimate heritabilities for milk yield (MY), fat percentage (%F), protein percentage (%P), length of lactation (LL), age of first calving (AFC) and calving interval (CI) and the genetic correlations among traits MY, %F and %P. The (co) variance components were estimated using multiple-trait analysis by Bayesian inference method, applying an animal model, through Gibbs sampling. The model included the fixed effects of contemporary groups (herd-year and calving season), number of milking (2 levels), and age of cow at calving as (co) variable (quadratic and linear effect). The additive genetic, permanent environmental, and residual effects were included as random effects in the model. Estimated heritability values for MY, % F, % P, LL, AFC and CI were 0.24, 0.34, 0.40, 0.09, 0.16 and 0.05, respectively. The genetic correlation estimates among MY and % F, MY and % P and % F and % P were -0.29, -0.18 and 0.25, respectively. The production of milk and its constituents showed enough genetic variation to respond to a selection program. Negative estimates of genetic correlations between milk production and its components suggest that selection entails a reduction in the other.

Estimates of genetic parameters for total milk yield over multiple ages in Brazilian Murrah buffaloes using different models

The objective of this study was to estimate variance components and genetic parameters for accumulated 305-day milk yield (MY305) over multiple ages, from 24 to 120 months of age, applying random regression (RRM), repeatability (REP) and multi-trait (MT) models. A total of 4472 lactation records from 1882 buffaloes of the Murrah breed were utilized. The contemporary group (herd-year-calving season) and number of milkings (two levels) were considered as fixed effects in all models. For REP and RRM, additive genetic, permanent environmental and residual effects were included as random effects. MT considered the same random effects as did REP and RRM with the exception of permanent environmental effect. Residual variances were modeled by a step function with 1, 4, and 6 classes. The heritabilities estimated with RRM increased with age, ranging from 0.19 to 0.34, and were slightly higher than that obtained with the REP model. For the MT model, heritability estimates ranged from 0.20 (37 months of age) to 0.32 (94 months of age). The genetic correlation estimates for MY305 obtained by RRM (L23.res4) and MT models were very similar, and varied from 0.77 to 0.99 and from 0.77 to 0.99, respectively. The rank correlation between breeding values for MY305 at different ages predicted by REP, MT, and RRM were high. It seems that a linear and quadratic Legendre polynomial to model the additive genetic and animal permanent environmental effects, respectively, may be sufficient to explain more parsimoniously the changes in MY305 genetic variation with age.

Genetic parameters for earnings in Quarter Horse

In this study, we estimated the heritability (h(2)) of earnings in the Quarter Horse in order to evaluate the inclusion of this trait in breeding programs. Records from 14,754 races of 2443 horses from 1978-2009 were provided by Sorocaba Hippodrome, Sao Paulo, Brazil. All ancestors of the registered horses were included in the pedigree file until the 4th generation. Log-transformed performance measures (LPM) were analyzed for animals aged 2, 3, and 4 years and during their entire career. The h(2) estimates were obtained using a multi-trait model and Gibbs sampling that included the effects of sex, year of race, and animal in all analyses. Five analyses were performed: 1 in which LPM was divided by the number of prizes, 1 in which LPM was divided by the number of race starts, and 3 analyses that included the number of prizes, number of race starts, and both (LPM_cNPS) as covariates. Analysis was performed with and without inclusion of the maternal effect. Models were compared based on the deviance information criterion and LPM_cNPS including maternal effects was found to be the best model. The h(2) estimates and standard deviation obtained using model LPM_cNPS were 0.19 +/- 0.08, 0.21 +/- 0.08, 0.22 +/- 0.09, and 0.21 +/- 0.07 for earnings at 2, 3, and 4 years of age and total career, respectively. Our analyses indicate that earnings are subject to selection and can be included in breeding programs to improve the racing performance of Quarter Horses.

Ranking of Nellore animals in cattle championships: genetic parameters and correlations with production traits

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Spermatozoon ultrastructure and semen parameters of Brycon vermelha (Characiformes, Characidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Validity and behaviour of tropospheric gradients estimated by GPS in Corsica

Estimation of tropospheric gradients in GNSS data processing is a well-known technique to improve positioning (e.g. Bar-Sever et al., 1998; Chen and Herring, 1997). More recently, several authors also focused on the estimation of such parameters for meteorological studies and demonstrated their potential benefits (e.g. Champollion et al., 2004). Today, they are routinely estimated by several global and regional GNSS analysis centres but they are still not yet used for operational meteorology.This paper discusses the physical meaning of tropospheric gradients estimated from GPS observations recorded in 2011 by 13 permanent stations located in Corsica Island (a French Island in the western part of Italy). Corsica Island is a particularly interesting location for such study as it presents a significant environmental contrast between the continent and the sea, as well as a steep topography.Therefore, we estimated Zenith Total Delay (ZTD) and tropospheric gradients using two software: GAMIT/GLOBK (GAMIT version 10.5) and GIPSY-OASIS II version 6.1. Our results are then compared to radiosonde observations and to the IGS final troposphere products. For all stations we found a good agreement between the ZWD estimated by the two software (the mean of the ZWD differences is 1 mm with a standard deviation of 6 mm) but the tropospheric gradients are in less good agreement (the mean of the gradient differences is 0.1 mm with a standard deviation of 0.7 mm), despite the differences in the processing strategy (double-differences for GAMIT/GLOBK versus zero-difference for GIPSY-OASIS).We also observe that gradient amplitudes are correlated with the seasonal behaviour of the humidity. Like ZWD estimates, they are larger in summer than in winter. Their directions are stable over the time but not correlated with the IWV anomaly observed by ERA-Interim. Tropospheric gradients observed at many sites always point to inland throughout the year. These preferred directions are almost opposite to the largest slope of the local topography as derived from the world Digital Elevation Model ASTER GDEM v2. These first results give a physical meaning to gradients but the origin of such directions need further investigations.

Genetic parameters for body weight in meat quail

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Genetic parameters and trends of morphometric traits of GIFT tilapia under selection for weight gain

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)