Revisiting Biodiversity of Crop Genepools

Abstract

Crop diversity has typically served as a source of novel variants for breeding programs, focusing on yield, quality and nutrition [1]. More recently, it has also assisted addressing basic questions in the field of genetics such as the repeatability of the domestication process [2-4], and the nature of the migration-selection balance in the face of mutation [5-8] and recombination rate variation [9]. Meanwhile, going beyond crop diversity and exploring crop wild relatives is equally promising, specially in the face of adaptation to current climate change [10]. Wild accessions offer an expanded genepool in terms of phenotypic innovation [11] and genetic diversity [12]. For instance, the wild is likely to exhibit pre-adapted variants advantageous to polygenic adaptation [13], such as drought [14-18] and heat [19,20] tolerance. However, merging crop and wild genepools remains challenging from a technical point of view due to phenological and genetic incompatibilities, sometimes bridged via recurrent backcrossing schemes, not to mention the adoption gaps when handling wild materials and early landraces with the potential to serve as novel crops [21]. Hence, leveraging novel approaches [10,19,22] are urgently required to better couple agro- and bio-diversity, both in current hotspots as well as in evolutionary cradles [23]. Of particular interest are the tropical regions [24,25], which not only maintain unparsed diversity [26] but are also the most vulnerable in terms of climate change [27] and crops’ market volatility.