Adaptability and stability with multivariate definition of macroenvironments for wheat yield in Rio Grande do Sul

The objective of this work was to evaluate the adaptability, stability, and environmental stratification of wheat (Triticum aestivum) grown in 20 environments, in the state of Rio Grande do Sul, Brazil. The experiments were performed during four crop years, in five wheat growing regions, considering 20 distinct growing environments. In the presence of genotype x environment (GxE) interaction, the additive main effects and multiplicative interaction analysis (AMMI) method was used. This method combines variances of additive effects of genotypes and environments with the multiplicative effects of GxE interaction, and the obtained scores are displayed in biplot graphs, using the principal component analysis. The environments stratified by the factor analysis, and the macroenvironments were defined according to grain yield behavior. The patterns of adaptability and phenotypic stability for genotypes 'BRS 327', 'BRS 331', 'Fundacep Raízes', 'BRS 328', and 'BRS Guamirim' were obtained through the multivariate biometric approaches AMMI and the factor analysis. The definition of macroenvironments is intrinsic to peculiarities of the crop year in the state of Rio Grande do Sul, and there is similarity between the municipalities of Santo Augusto, Cachoeira do Sul, and São Luiz Gonzaga, as well as between Cachoeira do Sul and São Gabriel. Resumo: O objetivo deste trabalho foi avaliar a adaptabilidade, a estabilidade e a estratificação ambiental de trigo (Triticum aestivum) em 20 ambientes, no estado do Rio Grande do Sul, Brasil. Os experimentos foram realizados durante quatro anos agrícolas, em cinco regiões de cultivo, tendo-se considerado 20 ambientes distintos. Na presença da interação genótipo x ambiente (GxA), utilizou-se o método “additive main effects and multiplicative interaction analysis” (AMMI). Este método combina as variâncias dos efeitos aditivos dos genótipos e dos ambientes com os efeitos multiplicativos da interação GxA, e os escores obtidos são mostrados em gráficos biplot, com uso de análise de componentes principais. A estratificação dos ambientes foi obtida com análise fatorial, e os macroambientes foram definidos de acordo com o comportamento do rendimento de grãos. Os padrões de adaptabilidade e estabilidade fenotípica dos genótipos 'BRS 327', 'BRS 331', 'Fundacep Raízes', 'BRS 328' e 'BRS Guamirim' foram obtidos por meio dos métodos biométricos multivariados AMMI e análise de fatores. A definição de macroambientes é intrínseca a peculiaridades