Cultivated rice varieties are all diploid, and polyploidization of rice has long been desired because of its advantages in genome buffering, vigorousness, and environmental robustness. However, a workable route remains elusive. Here, we describe a practical strategy, namely de novo domestication of wild allotetraploid rice. By screening allotetraploid wild rice inventory we identified one genotype of O. alta (CCDD), Polyploid Rice 1 (PPR1), and established two important resources for its de novo domestication: 1) an efficient tissue culture, transformation and genome editing system, and 2) a high-quality genome assembly discriminated into two subgenomes of 12 chromosomes apiece. With these resources we show that six agronomically important traits could be rapidly improved by editing O. alta homologs of the genes controlling these traits in diploid rice. Our results demonstrate the possibility that de novo domesticated allotetraploid rice can be developed into a new staple cereal to strengthen world food security.