Stepwise construction of the path to doubled haploid breeding in sorghum.

Abstract

Doubled haploid (DH) breeding greatly accelerates crop improvement, but efficient in vivo haploid induction has remained limited primarily to maize because readily available haploid inducers are lacking in other species. Here, we establish a complete DH breeding pipeline for sorghum by overcoming this key limitation. Using genome editing, we developed maternal haploid inducers that achieved haploid induction rates up to 16.04% in the P898012 background, with an average of 12.18% across 92 diverse crosses (15,156 seeds; various genetic backgrounds and environments). A dual-marker system combining fluorescence and pigmentation enabled reliable haploid identification. By optimizing a scalable emasculation protocol and using sorghum's naturally high rate of chromosome doubling, we established an efficient in planta DH production process. This framework provides a practical, transferable approach to implementing DH technology in sorghum and other crops.