Genomics-based discrimination of 2n gamete formation mechanisms in polyploids: a case study in nonaploid <i>Diospyros kaki</i> ‘Akiou’

Abstract

AbstractUnreduced gametes (2n gametes), possessing double the haploid genome, whatever ploidy that happens to be, are a common source of ploidy variation in plant populations. First and second division restitution (FDR and SDR) are the dominant mechanisms of 2n gamete production; all else being equal, FDR gametes have a higher degree of heterozygosity, thus they are advantageous in breeding. The discrimination of these mechanisms from the consequence of hybridization is challenging, especially in higher polyploids, and usually requires information on centromere location. In this study, we propose a genotyping-based strategy to uncover the mechanisms of 2n gamete formation in progeny that has a higher ploidy than its parents. Simulation of 2n gamete production revealed that FDR and SDR pathways can be discriminated based on allele transmission patterns alone without information on centromere location. We applied this strategy to study the formation mechanism of a nonaploid Diospyros kakiD. kaki