01701naa a2200229 a 450000100080000000500110000800800410001910000240006024500960008426000090018052009530018965000190114265300310116165300260119265300260121865300230124465300510126765300240131865300200134270000180136277300910138018633662010-10-18       2010    bl uuuu     u00u1 u    #d1 aFELIPE, C. R. de P.  aComparison of estimation and prediction methods of genotypic means in maize variety trials.  c2010  aThe objective of this study was to assess different statistical approaches to estimating or predicting genotypic means of maize varieties in lattice experiments. The following models were evaluated: fixed model (FF), mixed model with random block effect (AF), mixed model with random treatment effect (FA), random model (AA), and shrinkage James-Stein estimator (JS). Forty-seven experiments were analyzed, each one with three replications and 15 to 28 treatments. The mean of two check cultivars (controls) per growing season was used as reference for the selection. In most experiments, the rate of genotypes selected by the shrinkage approaches (FA, AA and JS) was lower than by the FF and AF models, which also tended to select low-yielding genotypes, even when the genotypic determination coefficient (h2’) was low. At high h2’ levels the genotypes selected by the different approaches were quite coincident, although the ranking differed.  aBreeding value  aEnsaios varietais de milho  aEstimador James-Stein  aJames-Stein estimator  aLinear mixed model  aMétodos de predição de médias genotípicas  aModelo linear misto  aValor genético1 aDUARTE, J. B.  tCrop Breeding and Applied Biotechnology, Londrinagv. 10, n. 2, p. 147-153, June 2010.