Clonal seeds in hybrid rice using CRISPR/Cas9

Heterosis, the observation that first generation hybrids outcompete the parental lines, is widely used in increasing the productivity and yield of agricultural crops. However, heterosis is lost in the following generations because of genetic segregation. In addition, the high cost of hybrid seed production hinders the application of heterosis in many crops. Clonal reproduction through seeds could be revolutionary for agriculture by allowing self-propagation of F1 hybrids. Here we show that heterozygosity of F1 hybrid rice can be fixed and thus propagated without additional crossing. First, we showed that multiplex editing of three key meiotic genes in hybrid rice leads to the production of clonal diploid gametes and tetraploid seeds. Next, editing of the MATRILINEAL (MTL) gene that involved in fertilization results in the induction of haploid seeds in hybrid rice. By simultaneous editing of these four endogenous genes in hybrid rice using the CRISPR/Cas9 system, we obtained in one generation plants able to propagate clonally through seeds. This opens the possibility to fix heterozygosity of hybrid varieties in food crops.