Simultaneous breeding for expansion volume and grain yield in popcorn (Zea mays L.) is difficult because of negative correlation between these traits. The use of selection indexes allows to overcome this difficulty. In 1997/1998, at Embrapa-Centro Nacional de Pesquisa de Milho e Sorgo, in Sete Lagoas, MG, Brazil,166 half-sib families from CMS-43 popcorn were evaluated, using random blocks design. The selection indexes used were Smith and Hazel, Pesek & Baker, Elston and Williams. The selection index of Smith and Hazel allowed larger predicted gains in more traits, and on the contrary, the prediction using the selection index of Williams was insignificant. The use of selection indexes allows simultaneous prediction of gains in the two main traits.
Zea mays; agronomic characters; breeding methods
