Heterosis arising from hybrid breeding has been instrumental in the improvement of crop yield and quality1,2. In self-pollinating crops, the use of male-sterile lines facilitates the production of hybrid seeds3. However, hybrid breeding in asexually propagated crops such as potato (Solanum tuberosum L.) presents challenges not only in hybrid seed production but also due to competition between above-ground (fruit) and below-ground (tuber) sinks. Here we developed self-incompatible homozygous diploid potatoes and hybrids through haploid breeding. This approach enables large-scale, low-cost hybrid seed production and eliminates aerial fruit formation, thereby avoiding sink competition between fruits and tubers and achieving a streamlined breeding design. Our strategy elevates the harvest index of hybrid potatoes, offering a paradigm for using heterosis and maximizing yield potential in asexually propagated crops.
