Adaptability and stability of maize varieties using mixed model methodology
Flávia Ferreira Mendes, Lauro José Moreira Guimarães, João Cândido Souza, Paulo Evaristo Oliveira Guimarães, Cleso Antônio Patto Pacheco, Jane Rodrigues de Assis Machado, Walter Fernandes Meirelles, Adelmo Resende da Silva and Sidney Netto Parentoni
Abstract – The objective of this study was to evaluate the performance, adaptability and stability of corn cultivars simultaneously in unbalanced experiments, using the method of harmonic means of the relative performance of genetic values. The grain yield of 45 cultivars, including hybrids and varieties, was evaluated in 49 environments in two growing seasons. In the 2007/2008 growing season, 36 cultivars were evaluated and in 2008/2009 25 cultivars, of which 16 were used in both seasons. Statistical analyses were performed based on mixed models, considering genotypes as random and replications within environments as fixed factors. The experimental precision in the combined analyses was high (accuracy estimates > 92 %). Despite the existence of genotype x environment interaction, hybrids and varieties with high adaptability and stability were identified. Results showed that the method of harmonic means of the relative performance of genetic values is a suitable method for maize breeding programs.