Potential genetic gains from targeted recombination versus recurrent selection for maize yield and moisture

Recurrent selection is a proven method and targeted recombination is a potential method for achieving genetic gain. Our objectives were to determine the (1) equivalency in predicted gains between cycles of recurrent selection and targeted recombination in maize (Zea mays L.), (2) correspondence between targeted-recombination positions when gains from nontargeted chromosomes are considered versus ignored, and (3) trade-offs in predicted gains for yield and moisture in targeted recombination. From genomewide marker effects for 2911 single nucleotide polymorphism loci in 270 biparental populations, we obtained predicted gains from fixed numbers of targeted recombinations and compared these gains to the genotypic-value distributions of doubled haploids obtained from different cycles of simulated recurrent selection. On average, it took three cycles of single-trait recurrent selection to obtain at least a few doubled haploid lines with the same performance achieved with nine or 10 targeted recombinations in Cycle 0. Results indicated that when targeting recombinations across the genome, gains from segregation on nontargeted chromosomes do not need to be considered. Predicted increases in yield were associated with increases in moisture. Given the logistics of pyramiding targeted recombinations and the lack of mature technologies for routine targeted recombination, recurrent selection is currently the preferred approach for accumulating favorable recombinations.