Abstract

Genetic breeding involves the recombination and selection of various valuable genes. Meiotic crossover (CO) promotes the generation of new allelic combinations on chromosomes, which is essential for breeding elite varieties (Wijnker and de Jong, 2008). An increase in CO promotes genetic diversity, whereas a decrease can rapidly stabilize excellent traits (Mercier et al., 2015). Furthermore, the complete elimination of CO facilitates heterotic fixation during apomixis (Wang et al., 2019). However, the number and distribution of COs are tightly restrained in crops, severely hindering agricultural breeding (Crismani et al., 2012). To date, many meiotic genes involved in CO formation have been identified in different organisms. Unfortunately, null mutations in these genes usually cause infertility, thus preventing direct use of the mutants in crop breeding.