EXPECTED AND REALIZED GAINS IN THE CMS-39 MAIZE POPULATION AFTER 3 CYCLES OF HALF-SIB FAMILY SELECTION

The CMS-39 maize population synthesized by die National Center of Rese arch for Maize and Sorghum (CNPMS/EMBRAPA) was submitted to half-sib f amily selection for grain yield. Populations representing the original cycle (C-o), and cycles I, II, and III, were evaluated in randomized complete blocks with ten replications in Sete Lagoas, Lavras, Ribeirao Vermelho, and Santo Antonio do Amparo, Minas Gerais State, Brazil. Th e purpose was to evaluate die observed gain from selection and to comp are it with the gain expected based on parameter estimates at each sel ection cycle. Tile realized gain per cycle, reported as the average fo r the four cycles was 3.6%. This value was smaller than the average ex pected gain per cycle, which was 7.2%. The main reasons for the non-ag reement of these estimates are discussed.