Synthetic apomixis promises to fix hybrid vigour through clonal seeds, yet practical implementation has been limited by low efficiency and reduced fertility. A new study identifies a sperm cell-specific transcription factor, HUAXU, that can trigger fertilization-independent embryogenesis when coupled with clonal gametogenesis, achieving near-complete clonal seed production in hybrid rice with minimal yield penalty. This work provides a mechanistic insight into the paternal activation of embryogenesis and offers a scalable strategy for fixing heterosis in crops.