Crossovers (COs), that drive genetic exchange between homologous chromosomes, are strongly biased toward subtelomeric regions in plant species. Manipulating the rate and positions of COs to increase the genetic variation accessible to breeders is a longstanding goal. Use of genome editing reagents that induce double-stranded breaks (DSBs) or modify the epigenome at desired sites of recombination, and manipulation of CO factors, are increasingly applicable approaches for achieving this goal. These strategies for ‘controlled recombination’ have potential to reduce the time and expense associated with traditional breeding, reveal currently inaccessible genetic diversity, and increase control over the inheritance of preferred haplotypes. Considerable challenges to address include translating knowledge from models to crop species and determining the best stages of the breeding cycle at which to control recombination.

驱动同源染色体之间的遗传交换的交换（CO）强烈偏向植物物种中的亚端粒区域。操纵CO的速率和位置以增加育种者可获得的遗传变异是一个长期的目标。用于诱导双链断裂（DSB）或修饰期望的重组位点的表观基因组的基因组编辑试剂的使用，以及对CO因子的操纵，是实现该目标的越来越有用的方法。这些“可控重组”策略具有减少与传统育种相关的时间和费用，揭示当前无法获得的遗传多样性以及增强对优选单倍型遗传的控制的潜力。