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A new method to estimate genetic gain in annual crops

1998; Brazilian Society of Genetics; Volume: 21; Issue: 4 Linguagem: Inglês

10.1590/s1415-47571998000400024

1678-4685

F. Breseghello, Orlando Peixoto de Morais, P. H. N. Rangel,

Genetic and phenotypic traits in livestock

The genetic gain obtained by breeding programs to improve quantitative traits may be estimated by using data from regional trials. A new statistical method for this estimate is proposed and includes four steps: a) joint analysis of regional trial data using a generalized linear model to obtain adjusted genotype means and covariance matrix of these means for the whole studied period; b) calculation of the arithmetic mean of the adjusted genotype means, exclusively for the group of genotypes evaluated each year; c) direct year comparison of the arithmetic means calculated, and d) estimation of mean genetic gain by regression. Using the generalized least squares method, a weighted estimate of mean genetic gain during the period is calculated. This method permits a better cancellation of genotype x year and genotype x trial/year interactions, thus resulting in more precise estimates. This method can be applied to unbalanced data, allowing the estimation of genetic gain in series of multilocational trials.