Genomic estimated selection criteria and parental contributions in parent selection increase genetic gain of maternal haploid inducers in maize.

Key message: Parental combinations determined by genomic estimated usefulness and parental contributions of the lines in bridging population can enhance the genetic gain of traits of interest in maternal haploid inducer breeding. Parent selection in crosses aligns well with the quantitative trait performance in the progenies. We herein take advantage of estimated genetic values (EGV) and usefulness criteria (UC) of bi-parental combinations by genomic prediction (GP) to compare the empirical performance of doubled haploid inducer (DHI) progenies of eight elite inducers crosses in a half-diallel. We used parental contribution and discovery of superiors from elite-by-historical bridging populations to enhance genetic gain for long-term selection. In this empirical study, the narrow-sense heritabilities of four traits of interest (Days to flowering, DTF; haploid induction rate, HIR; plant height, PHT; Total primary branch length, PBL) in DHI population were 0.81, 0.71, 0.45 and 0.46, respectively. The genomic estimated EGV_Mid/Mean and EGV/UC_Inferior was significantly correlated with the sample mean of progenies and inferiors in four traits in the breeding and bridging population. EGV/UC_Superior were significantly correlated with the mean of superiors in DTF, PHT, and PBL in breeding and bridging populations. The genomic estimated parent contributions in DH progenies of bridging populations enabled discovery of favorable genome region from historical inducers to improve the genetic gain of HIR for long-term selection.