Genome-Wide Association and Prediction of Male and Female Floral Hybrid Potential Traits in Elite Spring Bread Wheat Genotypes

Hybrid wheat breeding is one of the most promising technologies for further sustainable
yield increases. However, the cleistogamous nature of wheat displays a major bottleneck for a successful
hybrid breeding program. Thus, an optimized breeding strategy by developing appropriate
parental lines with favorable floral trait combinations is the best way to enhance the outcrossing ability.
This study, therefore, aimed to dissect the genetic basis of various floral traits using genome-wide
association study (GWAS) and to assess the potential of genome-wide prediction (GP) for anther
extrusion (AE), visual anther extrusion (VAE), pollen mass (PM), pollen shedding (PSH), pollen
viability (PV), anther length (AL), openness of the flower (OPF), duration of floret opening (DFO) and
stigma length. To this end, we employed 196 ICARDA spring bread wheat lines evaluated for three
years and genotyped with 10,477 polymorphic SNP. In total, 70 significant markers were identified
associated to the various assessed traits at FDR  0.05 contributing a minor to large proportion of the
phenotypic variance (8–26.9%), affecting the traits either positively or negatively. GWAS revealed
multi-marker-based associations among AE, VAE, PM, OPF and DFO, most likely linked markers,
suggesting a potential genomic region controlling the genetic association of these complex traits.
Of these markers, Kukri_rep_c103359_233 and wsnp_Ex_rep_c107911_91350930 deserve particular
attention. The consistently significant markers with large effect could be useful for marker-assisted
selection. Genomic selection revealed medium to high prediction accuracy ranging between 52% and
92% for the assessed traits with the least and maximum value observed for stigma length and visual
anther extrusion, respectively. This indicates the feasibility to implement genomic selection to predict
the performance of hybrid floral traits with high reliability.