Abstract:
Yield trials demand significant
time and resources, necessitating efficient
data collection on parental lines to optimise
breeding programs and reduce costs. This
study assessed the correlation between
parental traits and hybrid performance,
consistency, and predictability of trait
expression in F1 hybrids and the heterotic
advantage of agronomic traits. A total of 82
parental lines (79 lines and 3 testers) and 237
testcrosses were evaluated alongside 3
standard checks under low- and optimum-soil
nitrogen (N) conditions at the Institute for
Agricultural Research experimental fields in
Zaria and Mokwa during the 2019/20 and
2020/21 growing seasons. Significant genetic
variability was observed among parental lines
and testcrosses, offering strategic breeding
opportunities. Grain yield reductions under
low-N conditions (35–95% in inbreds and
1.3–89% in hybrids) highlighted the impact
of N stress and the need for N tolerance in
maize genotypes. Correlation analysis and
repeatability results linked yield
improvement in low-N tolerant maize hybrids
to the selection of parental lines with superior
performance in traits, such as grain yield,
stay-green characteristics, and flowering
traits. Parental lines P69 and P14, which
showed high tolerance to low N and
consistent high yields, were identified as
valuable genetic resources. Among the
hybrids, P65×T2, P66×T3, and P66×T2 stood
out, with grain yields exceeding 6000 kg/ha,
representing a 42% yield advantage over the
best check. These hybrids also demonstrated
a high heterotic advantage over their parents
and standard checks, indicating their potential
for adoption as commercial hybrids in
Nigeria.
