Harnessing clonal gametes in hybrid crops to engineer polyploid genomes

Abstract Heterosis boosts crop yield; however, harnessing additional progressive heterosis in polyploids is challenging for breeders. We bioengineered a ‘mitosis instead of meiosis’ ( MiMe ) system that generates unreduced, clonal gametes in three hybrid tomato genotypes and used it to establish polyploid genome design. Through the hybridization of MiMe hybrids, we generated ‘4-haplotype’ plants that encompassed the complete genetics of their four inbred grandparents, providing a blueprint for exploiting polyploidy in crops.