Plant domestication and crop improvement have resulted in reduced genetic diversity in most of our cultivated crops, thus limiting their potential to adapt to future challenges (Byrne et al., 2018; Keneni, Bekele, Imtiaz, & Dagne, 2012; Tanksley & McCouch, 1997; Swarup et al., 2021). One response to mitigate the impact of climate change on agricultural systems is to develop improved varieties that are genetically tolerant or resistant to the new range of abiotic and biotic challenges. Improvement via crop breeding requires access to novel variants of genes for complex adaptive traits. Crop wild relatives (CWR) and landraces are potentially valuable sources of these alleles (Cossani & Reynolds, 2015; Seiler, QiL, & Marek, 2017). However, these materials are often difficult to work with and require genetic selection to make them agronomic and useful in a breeding program, a process commonly referred to as ‘pre-breeding. This term was first used by Rick (1984) and refers to a wide range of activities designed to (i) identify beneficial traits in CWR and other plant genetic resources (PGR), and (ii) transfer these traits into breeding lines (Ortiz, 2002; Sharma, Upadhyaya, Varshney, & Gowda, 2013). Pre-breeding forms a bridge between the gene banks that hold and safeguard CWR and landraces, and breeders and farmers who use them.
