01824naa a2200265 a 450000100080000000500110000800800410001910000150006024500510007526000090012650000830013552010510021865000220126965000140129165000140130565000160131965000250133565000130136065300130137370000240138670000200141070000160143070000260144677300860147211061142018-10-30       2002    bl uuuu     u00u1 u    #d1 aVACARO, E.  aCombining ability of twelve maize populations.  c2002  aTítulo em português: Capacidade combinatória de doze populações de milho.  aGenetic progress depends on germplasm quality and breeding methods. Twelve maize populations and their crosses were evaluated to estimate combining ability and potential to be included as source populations in breeding programs. Plant height, point of insertion of the first ear, number of ears per plant, number of grains per ear, root and stalk lodging and grain yield were studied in two locations in Brazil, during the 1997/98 season. Genotype sum of squares was divided into general (GCA) and specific (SCA) combining ability. Results indicated the existence of genetic divergence for all traits analyzed, where additive effects were predominant. The high heterosis levels observed, mainly in Xanxerê, suggested the environmental influence on the manifestation of this genetic phenomenon. Populations revealed potential to be used in breeding programs; however, those more intensively submitted to selection could provide larger genetic progress, showing the importance of population improvement for the increment of the heterosis in maize.  agenetic variation  agermplasm  aheterosis  aGermoplasma  aVariação Genética  aZea Mays  aheterose1 aBARBOSA NETO, J. F.1 aPEGORARO, D. G.1 aNUSS, C. N.1 aCONCEIÇÃO, L. D. H.  tPesquisa Agropecuária Brasileira, Brasília, DFgv. 37, n. 1, p.67-72, jan. 2002