Rapid formation of stable autotetraploid rice from genome-doubled F1 hybrids of japonica-indica subspecies

We uncover factors that constrain the genomic composition of the rice tetraploid recombinant inbred lines, including overall asymmetric parental contribution, exclusive uniparental segment retention, and HE-enabled stochastic segmental re-patching of some whole-chromosomes to one parent-state. Intriguingly, some TRILs that have high fertility and grain-yield, which concur with largely stabilized meiosis, also evolved enhanced resilience to abiotic stresses. Our findings have implications for unexpected evolutionary possibility of HE-catalyzed allo-to-auto polyploidy transitions in nature. In addition, this study suggests that new polyploid crops may be feasibly created using domesticated congeneric diploid subspecies as the initial hybridizing parents.