Correlated response to selection of testosterone levels and immunocompetence in lines selected for avian personality

2011 ◽  
Vol 81 (5) ◽  
pp. 1055-1061 ◽  
Author(s):  
Kees van Oers ◽  
Katherine L. Buchanan ◽  
Tanja E. Thomas ◽  
Pieter J. Drent
1981 ◽  
Vol 32 (3) ◽  
pp. 411 ◽  
Author(s):  
DG Pederson ◽  
AJ Rathjen

Nine sites used in a wheat breeding programme in South Australia were investigated. Of the six major sites, four occupy farmers' fields and two are located on experiment stations. The data analysed comprised grain yields of 31 genotypes grown in 31 trials over a 5-year period. Relative to that grown at non-station sites, wheat grown at the experiment-station sites generally had higher mean yields, higher coefficients of variation, and lower heritabilities. Data from a set of independently conducted trials were used to estimate the true yields of the 31 genotypes. A heritability of the correlated response to selection was then calculated for each breeding trial, and was generally found to be low for the experiment-station sites. Further investigation showed that the non-station sites are suitable for the selection of genotypes intended for low-yielding environments, and the station sites are better suited for the selection of genotypes intended for high-yielding environments. The optimum selection scheme was found to consist of several unreplicated trials per year, and at least four trials per year are necessary to avoid the possibility of a negative heritability of the correlated response to selection.


1973 ◽  
Vol 22 (1) ◽  
pp. 1-7
Author(s):  
W. R. Scowcroft

SUMMARYThe direct and correlated response to selection of scutellar microchaetae and scutellar bristles has been analysed by determining the contribution of the three major chromosomes, alone and in combination with each other, to the overall response. The results of the analysis confirm a previous finding, based on a formal statistical approach, that response to selection for microchaetae had highly pleiotropic effects on scutellar bristles. In lines selected, each for high and low microchaetae, genetic changes in the 2nd and 3rd chromosomes are pre-eminent and essentially equal. Inter-chromosomal interactions are of relatively minor importance in interpreting the response to selection for microchaetae but assume greater importance with respect to the correlated character. The results are discussed in terms of the genetic correlation between fitness and the character measured.


1961 ◽  
Vol 2 (3) ◽  
pp. 439-448 ◽  
Author(s):  
Hans Abplanalp

A method for obtaining linear estimates of heritability and genetic correlation is given. It is based, essentially, on selecting, from a pedigreed population, prospective parents for which estimates of average genotype and phenotype values are obtained; a regression of genotype on phenotype value is then determined from a straight line fitted through points representing the population mean genotype and phenotype on one hand and the mean genotype and phenotype of selected parents on the other.The method permits an evaluation of asymmetry in response for a trait selected in both directions, as well as asymmetry in correlated response to selection of two different traits, with data from a single pedigreed population.


1960 ◽  
Vol 11 (5) ◽  
pp. 836 ◽  
Author(s):  
CHS Dolling ◽  
RW Moore

The offspring of two families of medium Peppin Merino sheep, one family being selected for high and the other for low clean wool weight per head at 15-16 months of age under grazing conditions, have also been shown to differ significantly in the ratio of wool production to food eaten in pens, on a ration slightly above maintenance. These ratios were in the proportion 108 : 100, and the difference between the families can be taken as reflecting closely a difference in net efficiency of conversion of food to wool. It may be concluded that selection for high clean wool weight per head under grazing conditions had also resulted in the selection of more efficient animals. Clean wool production per head in the two families was in the ratio 110 : 100 in the pens, compared with 124 : 100 under grazing. The difference under grazing probably results from both the higher efficiency of the family selected for high clean wool weight and a higher grazing intake by this family.


2002 ◽  
Vol 80 (10) ◽  
pp. 2566 ◽  
Author(s):  
J. Estany ◽  
D. Villalba ◽  
M. Tor ◽  
D. Cubiló ◽  
J. L. Noguera

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