Die Covarianz zwischen Verwandten in einer gen‐orthogonalen Population. I. Allgemeine Theorie

Schnell, F. W.

doi:10.1002/bimj.19650070102

Cited by 21 publications

(15 citation statements)

References 29 publications

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“…There is a large body of quantitative-genetic literature studying the resemblence of genotypes in populations, which can potentially be used to derive genetic variance-covariance structures in a number of settings (Cockerham 1954;Schnell 1965;Stuber and Cockerham 1966;Falconer and Mackay 1996), including diallels and other crossing schemes. It is important to realize, however, that the underlying quantitative-genetic theory often makes a number of strong assumptions, which usually are not, and cannot be, fully met in practice (Nyquist 1991, p. 264 and p. 270; also see Holland et al 2003).…”

Section: Pedigree-based Blup Using the Coefficient Of Coancestrymentioning

confidence: 99%

BLUP for phenotypic selection in plant breeding and variety testing

et al. 2007

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Best linear unbiased prediction (BLUP) is a standard method for estimating random effects of a mixed model. This method was originally developed in animal breeding for estimation of breeding values and is now widely used in many areas of research. It does not, however, seem to have gained the same popularity in plant breeding and variety testing as it has in animal breeding. In plants, application of mixed models with random genetic effects has up until recently been mainly restricted to the estimation of genetic and nongenetic components of variance, whereas estimation of genotypic values is mostly based on a model with fixed effects. This paper reviews recent developments in the application of BLUP in plant breeding and variety testing. These include the use of pedigree information to model and exploit genetic correlation among relatives and the use of flexible variance-covariance structures for genotype-by-environment interaction. We demonstrate that BLUP has good predictive accuracy compared to other procedures. While pedigree information is often included via the so-called numerator relationship matrix ðAÞ, we stress that it is frequently straightforward to exploit the same information by a simple mixed model without explicit reference to the A-matrix.

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Section: Pedigree-based Blup Using the Coefficient Of Coancestrymentioning

confidence: 99%

BLUP for phenotypic selection in plant breeding and variety testing

et al. 2007

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“…Consider two loci, j and k, with two alleles, A-a and B-b, present in parents P1 and P2. Employing the statistical model proposed for hybrid populations (Griffing, 1962;Schnell, 1965) for the present case, the genotypic values of testcrosses resulting from the four possible types of gametes produced by the candidate population can be sub-divided in the following manner:…”

Section: The Genetic Modelmentioning

confidence: 99%

“…Here the parameters on the right-hand side are statistically defined using as a base of reference the gene-orthogonal population (Schnell, 1965) between tester T and the F2-derived population of the cross P1 x P2 in linkage equilibrium. Their dependence on the tester genotype is indicated by a superior T. Parameters dJ and d refer to half the average effect of a gene substitution at the loci j and k in the gamete from the candidate, respectively.…”

Section: The Genetic Modelmentioning

confidence: 99%

Expectation of means and variances of testcrosses produced from from F2 and backcross individuals and their selfed progenies

Melchinger

1987

Heredity

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A biometrical genetic model is presented for the testcross performance of genotypes derived from a cross between two pure-breeding lines. The model is applied to obtain the genetical expectations of first and second degree statistics of testcrosses established from F2, first and higher backcross populations and their selfing generations. Theoretically, the testcross mean of these populations is expected to be a linear function of the percentage of germplasm from each parent line in the absence of epistasis. In both F2 and backcross populations, the new arising testcross variance between sublines is halved with each additional generation of selfing. Special consideration is given to the effects of linkage and epistasis, and tests for their presence are provided. The results are discussed with respect to implications in "second cycle" breeding. It is concluded that the choice of base populations between F2 and first backcrosses can be made on the distributions of testerosses from the first segregating generation. Schnell's (1983) "usefulness" criterion is recommended for choosing the optimum type of base population.

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“…In addition, a and d refer to the additive and dominance effects (Falconer and Mackay 1996). For the hybrid population p1 3 p2, s (Griffing 1962;Schnell 1965). Assume that both populations p1 and p2 are combined into one synthetic, which is randomly intermated for several generations so that linkage equilibrium is reached.…”

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confidence: 99%

Impact of Interpopulation Divergence on Additive and Dominance Variance in Hybrid Populations

et al. 2007

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We present a theoretical proof that the ratio of the dominance vs. the additive variance decreases with increasing genetic divergence between two populations. While the dominance variance is the major component of the variance due to specific combining ability (s 2 SCA ), the additive variance is the major component of the variance due to general combining ability (s 2 GCA ). Therefore, we conclude that interpopulation improvement becomes more efficient with divergent than with genetically similar heterotic groups, because performance of superior hybrids can be predicted on the basis of general combining ability effects.

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Die Covarianz zwischen Verwandten in einer gen‐orthogonalen Population. I. Allgemeine Theorie

Cited by 21 publications

References 29 publications

BLUP for phenotypic selection in plant breeding and variety testing

BLUP for phenotypic selection in plant breeding and variety testing

Expectation of means and variances of testcrosses produced from from F2 and backcross individuals and their selfed progenies

Impact of Interpopulation Divergence on Additive and Dominance Variance in Hybrid Populations

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