Eighteen S3 selected inbred lines from two divergent
tropical maize populations (eight from BR-105 and ten
from BR-106) previously had their genetic distances surveyed
using four different marker systems (Lanza et al.,
1997; Benchimol et al., 2000; Barbosa et al., 2003). The
BR-105 population is an early-maturing synthetic with orange
flint kernels while the BR-106 population is an earlymaturing
composite with yellow dent kernels, both populations
having shown high levels of heterosis when crossed
and were assigned to distinct heterotic groups by Naspolini
Fº et al., (1981) and Souza Jr. et al., (1993). Detailed descriptions
of these populations are given in Lanza et al.
(1997) and Rezende and Souza Jr. (2000).
Total genomic DNA was isolated from a bulk of
five-week-old leaf tissue taken from 16 plants of each line,
then being isolated and purified by the method of
Hoisington et al. (1994).