Data and code for: Realized genetic gains via recurrent selection in a tropical maize haploid inducer population and optimizing simultaneous selection for the next cycles

Plant breeders widely use recurrent selection schemes to increase the
frequency of favorable alleles for quantitative traits in a population.
Although simultaneous selection is complex because it involves several
traits combined with selection cycles, the use of selection indexes (SI)
is applied to increase the chance of success of the breeding program. As
many indices are available in the literature, simulations can help
breeders to determine which selection index can be better adjusted
considering the selection goals, the intensity, and the genetic
correlation among traits over breeding cycles. In this context, we
estimated the realized genetic gains in a tropical maize haploid inducer
population after two cycles of recurrent selection, using external testers
and optimizing the simultaneous selection for this breeding population in
the long-term via stochastic simulations. Furthermore, we proposed a new
approach to optimize the initial weights by applying the Smith-Hazel
method to maximize the genetic gains for all traits in a balanced way.
Overall, the estimated gains in real induction rate were about 63% per
cycle, improving the population performance from 0.8 to 2.8%. Moreover,
our results confirm that the traditional Smith-Hazel approach outperformed
other methods for long-term response to selection. Finally, recurrent
selection with external testers may be a suitable method to improve the
haploid induction rate in tropical maize populations.