Adaptability and stability of soybean advanced lines of semi early cycle for rust resistance

Abstract

This research work was carried out to verify the adaptability and phenotypic stability of soybean inbred lines of semi early cycle, using rust severity as the selection trait for partial resistance. The strains were evaluated during the growing seasons of 2007/08 and 2008/09, in the locations of Uberlândia and Uberaba, MG, Campo Alegre de Goiás and Senador Canedo, GO, using a randomized complete block design with three replications. Rust severity was evaluated by visual assessment of the leaflets at the medial third of five plants in each plot. By using disease severity, it was estimated: the mean absolute rate of disease progress (r), the area under the disease progress curve (AUDPC) and the partial resistance factor (PRF). Adaptability and stability of the strains were estimated by the methods proposed by Eberhart and Russell, as well as by the AMMI method. It was found that the strains which were the most resistant to rust, in general, also showed the best adaptability and stability.O objetivo deste trabalho foi verificar a adaptabilidade e estabilidade fenotípica de linhagens de soja de ciclo de maturação semiprecoce, utilizando a severidade da ferrugem asiática como parâmetro de seleção para resistência parcial. As linhagens foram avaliadas nas safras 2007/08 e 2008/09, nos municípios de Uberlândia, MG, Uberaba, MG, Campo Alegre de Goiás, GO e Senador Canedo, GO, utilizando-se o delineamento experimental de blocos casualizados com três repetições. A severidade da ferrugem asiática foi obtida pela estimativa visual dos folíolos. Foi estimada a taxa de progresso absoluta média da doença (r), área abaixo da curva de progresso da doença (AACPD) e também o fator de resistência parcial (FRP). Realizou-se análise de adaptabilidade e estabilidade pelo método de Eberhart e Russel e o método multivariado AMMI. Constatou-se que as linhagens que se mostraram mais resistentes à ferrugem, em geral, também foram as de melhor adaptabilidade e estabilidade.