Abstract

Improved plant varieties are important in our attempts to face  the challenges of a growing human population and limited  planet resources. Plant breeding relies on meiotic crossovers  to combine favourable alleles into elite varieties 1 . However,  meiotic crossovers are relatively rare, typically one to three  per chromosome 2 , limiting the efficiency of the breeding pro- cess and related activities such as genetic mapping. Several  genes that limit meiotic recombination were identified in the  model species  Arabidopsis thaliana 2 . Mutation of these genes  in  Arabidopsis induces a large increase in crossover frequency.  However, it remained to be demonstrated whether crossovers  could also be increased in crop species hybrids. We explored  the effects of mutating the orthologues of  FANCM 3 ,  RECQ4 4 or FIGL1 5 on recombination in three distant crop species, rice  ( Oryza sativa ), pea ( Pisum sativum ) and tomato ( Solanum  lycopersicum ). We found that the single  recq4 mutation  increases crossovers about three-fold in these crops, sug - gesting that manipulating  RECQ4 may be a universal tool for  increasing recombination in plants. Enhanced recombination  could be used with other state-of-the-art technologies such  as genomic selection, genome editing or speed breeding 6 to  enhance the pace and efficiency of plant improvement.