Maternal Haploid Induction Through Egg Cell‐Specific Endopeptidases in Brassica napus : A Step Forward Towards Hybrid Fixation

ABSTRACT Hybrid fixation is an emerging breeding tool that eliminates the need to purchase costly hybrid seeds on an annual basis. However, this technique is limited to Arabidopsis, rice, and soybean with a severe issue of seed setting. Seed setting rate is affected due to targeting of cell division‐related genes and an increase in ploidy in each successive generation. These types of issues can be sorted out by identifying self‐haploid indication lines. Egg cell‐specific endopeptidases ( ECS ) play a role during gamete fusion/fertilization by avoiding polytuby and along with gamete fusion work as a haploid inducer in many crops. Here, we knock out Bn ECS1 , BnECS2 , and both together in Brassica napus ( B. napus ) by using the clustered regularly interspaced short palindromic repeats (CRISPR‐Cas9) gene editing system. Mutant population causes maternal/self‐haploid induction in B. napus . Self‐haploid induction will play a significant role in hybrid fixation, allowing hybrid plants to maintain their ploidy level without requiring additional hybridization with other haploid induction lines. Hence, our study provides a baseline for the development of hybrid fix plants in B. napus without an increase of ploidy in each successive generation.