CAB CROP BREEDING AND APPLIED BIOTECHNOLOGY

The aim of this study was to estimate the repeatability of some phenotypic stability parameters: reliability index (1), regression coefficient (b(0) e b(1)), ecovalence, and the mean of the absolute scores (MAS), and to check the implications of estimating stability parameters using a reduced number of environments. A dataset comprising 25 common bean lines assessed in 36 environments was used. These environments comprise different locations, sowing seasons, and years. Different experimental groups, from three to 18 environments, were simulated. For each group, analysis of variance was performed and the stability parameters were estimated. The greater repeatability estimates were observed for the mean (b(0)), followed by the 1 and b(1). Ecovalence and MAS had the lowest values for the repeatability estimates, which is not desirable for breeding programs aiming at selection for high stability. The phenotypic stability parameter should not be estimated from fewer than 12 environments.