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Expected and realized gains in the CMS-39 maize population after three cycles of half-sib family selection^*

Eder Ferreira Arriel^I; Magno Antonio Patto Ramalho^II; Cleso Antonio Patto Pacheco^III

^IUFPB/CSTR/DEF, Campus 7, Caixa Postal 64, 58700-970 Patos, PB, Brasil. Send correspondence to E.F.A.
^IIDepartamento de Biologia, Escola Superior de Agricultura de Lavras, Caixa Postal 37, 37200-000 Lavras, MG, Brasil
^IIICNPMS-EMBRAPA, Caixa Postal 151, 35700-970 Sete Lagoas, MG, Brasil

ABSTRACT

The CMS-39 maize population synthesized by the National Center of Research for Maize and Sorghum (CNPMS/EMBRAPA) was submitted to half-sib family selection for grain yield. Populations representing the original cycle (C₀), and cycles I, II, and III, were evaluated in randomized complete blocks with ten replications in Sete Lagoas, Lavras, Ribeirão Vermelho, and Santo Antônio do Amparo, Minas Gerais State, Brazil. The purpose was to evaluate the observed gain from selection and to compare it with the gain expected based on parameter estimates at each selection cycle. The realized gain per cycle, reported as the average for the four cycles was 3.6%. This value was smaller than the average expected gain per cycle, which was 7.2%. The main reasons for the non-agreement of these estimates are discussed.

Keywords: CMS-39 maize population; half-sib family selection.

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* Part of a thesis presented by E.F.A. to Escola Superior de Agricultura de Lavras (ESAL), in partial fulfillment of the requirements for the Maste's degree.