GENOTYPE BY ENVIRONMENT INTERACTION IN COWPEA LINES USING GGE BIPLOT METHOD

Portuguese. RESUMO O método GGE Biplot é eficiente em identificar genótipos favoráveis e ambientes ideais para avaliação. Portanto, o objetivo deste trabalho foi avaliar a interação genótipo por ambientes (G×A) de linhagens elite de feijão-caupi nos ensaios de valor de cultivo e uso (VCU) da Embrapa Meio-Norte, realizados nas regiões de Cerrado do Brasil, por meio de analises via GGE Biplot. Avaliou-se a produtividade de grãos em 40 genótipos de feijão-caupi, sendo 30 linhagens e 10 cultivares, durante três anos (2010, 2011 e 2012) em três locais: Balsas (BAL), São Raimundo das Mangabeiras (SRM) e Primavera do Leste (PRL). Os dados foram submetidos a análises de variância, a partir da qual foram obtidas as médias ajustadas para realizar a análise via GGE-Biplot. Os resultados gráficos revelam que houve variação no comportamento dos genótipos nos locais avaliados ao longo dos anos. As linhagens MNC02-675F-4-9 e MNC02-675F-4-10 apresentaram desempenhos de um genótipo ideal, com máxima produtividade aliada à boa estabilidade nos locais de avaliação. Houve a formação de três mega-ambientes que englobaram ambientes correlacionados positivamente. As linhagens MNC02-675F-4-9, MNC02-675F-9-3 e MNC02-701F-2 apresentaram o melhor desempenho médio dentro de cada mega-ambiente. O ambiente PRL10 e as linhagens próximas a este ambiente, como MNC02-677F-2, MNC02-677F-5 e a cultivar testemunha BRS-Marataoã, puderam ser classificados com maior confiabilidade, determinados basicamente pelos efeitos genotípicos, com G×A reduzida. A maioria dos ambientes avaliados foram ideais para avaliação da G×A, discriminando bem os genótipos. Portanto, a análise GGE-Biplot, permitiu selecionar genótipos com adaptabilidade e desempenhos superiores para ambientes específicos.

English. ABSTRACT The GGE Biplot method is efficien to identify favorable genotypes and ideal environments for evaluation. Therefore, the objective of this work was to evaluate the genotype by environment interaction (G×E) and select elite lines of cowpea from genotypes, which are part of the cultivation and use value tests of the Embrapa Meio-Norte Breeding Program, for regions of the Brazilian Cerrado, by the GGE-Biplot method. The grain yield of 40 cowpea genotypes, 30 lines and 10 cultivars, was evaluated during three years (2010, 2011 and 2012) in three locations: Balsas (BAL), São Raimundo das Mangabeiras (SRM) and Primavera do Leste (PRL). The data were subjected to analysis of variance, and adjusted means were obtained to perform the GGE-Biplot analysis. The graphic results showed variation in the performance of the genotypes in the locations evaluated over the years. The performance of the lines MNC02-675F-4-9 and MNC02-675F-4-10 were considered ideal, with maximum yield and good stability in the locations evaluated. There mega-environments were formed, encompassing environments correlated positively. The lines MNC02-675F-4-9, MNC02-675F-9-3 and MNC02-701F-2 had the best performance within each mega-environment. The environment PRL10 and lines near this environment, such as MNC02-677F-2, MNC02-677F-5 and the control cultivar (BRS-Marataoã) could be classified as those of greater reliability, determined basically by the genotypic effects, with reduced G×E. Most of the environments evaluated were ideal for evaluation of G×E, since the genotypes were well discriminated on them. Therefore, the selection of genotypes with adaptability and superior performance for specific environments through the GGE-Biplot analysis was possible.