Effect of heterosis on performance of mice across three environments.

Abstract

Performance of six genetic groups of mice was studied in three different environments in order to determine the effect of heterosis on consistency of performance in varied environments. Designed as a 3 x 6 factorial, data were analyzed using least squares analyses of variance. Genetic group effects, environmental effects, genetic group x environment interaction, and heterosis were examined for 42-d weight, age and weight at vaginal opening, age and weight at puberty, ovulation rate (determined by total corpora lutea), number of implantations, and number of fetuses at 10 d of gestation. Weight at vaginal opening, ovulation rate, implantation rate and total number of fetuses exhibited significant heterosis. Regression of these traits against an environmental index (mean performance of all genetic groups over environments) provided an estimate of stability of performance. In general, genetic groups exhibiting heterosis expressed more consistent performance across environments than pure lines did. We conclude that a stability model could be used to aid in identification of lines with consistent performance for production traits in variable environments.

Somatic development and embryo yield in crossbred F1 mice generated by different mating strategies

“…An option to overcome the negative effects of endogamy in somatic and reproductive parameters in mice experimental groups would be the production of outbreed populations specifically for this aim. Davis et al (1991) demonstrated the effect of heterosis on reproductive performance of mice in different environments, using a factorial crossing design. The aim of this study was to evaluate different mating strategies among endogamic strains to create F1 hybrid populations of mice, minimising the effect of the inbreeding depression in somatic development and embryo production.…”

Genotype by environment interaction estimated by using reaction norms in cattle

“…Others have evaluated performance of different strains or lines in multiple environments. For instance, Davis and Lamberson (1991) analyzed performance of six genetic groups of mice across three different environments. Their graphs depict a regression of each genetic group's performance against an environmental index for the traits ovulation rate, number of implantations, number of fetuses, and age at vaginal opening.…”

Genetic Analyses of Reproductive Traits in Maternal Lines of Rabbits and in their Diallel Cross / Análisis Genético de Caracteres Reproductivos en Líneas Maternales de Conejo y en su Cruzamiento Dialélico

“…In mice, Nielsen (1994) reported a significant response and in pigs, the experiment reported by Lamberson et al (1991) or the ones related to selection on hyperprolificacy (Bichard and David, 1985;Sorensen and Vernensen, 1991;Bidanel et al, 1994 andNoguera et al, 1997) has been demonstrated to be effective. However, the genetic progress of litter size at birth in pigs has been lower than expected (Southwood and Kennedy, 1991;Holl and Robison, 2003).…”

“…Research with mice (Bradford, 1969;Land and Falconer, 1969), swine (Zimmerman and Cunningham, 1975;Cunningham et al, 1979;Lamberson andDay,1986 andCasey et al, 1994) and rabbits Laborda et al ( , 2012a showed, in the same population after 10 generation of selection for ovulation rate, that direct response to selection for ovulation rate was relevant, but there was no correlated response on litter size (−0.15 kits), due to an increase in prenatal mortality.…”

“…However, postimplantation losses were mainly affected by the additive effect of the genes. Davis and Lamberson (1991) reported that the genetic group significantly affectedthe ovulation rate and the total number of foetuses, but not the total number of implantations.…”