Twenty maize

lines were crossed with six inbreds used as testers, with the

objective of examining their general and specific combining

ability and determine their usefulness in a hybridization

program. The crosses were evaluated in three environments

at Mexico during 1997. General combining ability (GCA)

and specific combining ability (SCA) effects were calculated

using a Line x Tester analysis. CML264 (1586 kg/ha) and

CML319 (1285 kg/ha) were the highest GCA lines in the

tropical and subtropical group, respectively. The highest

SCA effects were for the crosses CML322 x M.L.S4-1 (1651

kg/ha) and CML258 x SSE255-18-19 (1512 kg/ha). These

results indicate that it is possible to develop a hybrid program

using the best lines released by the International Maize and

Wheat Improvement Center (CIMMYT), and the best testers

from UAAAN.

Keywords: Lines, testers, GCA, SCA, hybrids.