%0 Journal Article
%T A new method to estimate genetic gain in annual crops
%A Breseghello
%A Fl¨˘vio
%A Morais
%A Orlando Peixoto de
%A Rangel
%A Paulo Hideo Nakano
%J Genetics and Molecular Biology
%D 1998
%I Sociedade Brasileira de Gen¨¦tica
%R 10.1590/S1415-47571998000400024
%X 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.
%U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S1415-47571998000400024&lng=en&nrm=iso&tlng=en