Reaching back through the domestication bottleneck: tapping wild plant biodiversity for crop improvement

Crop domestication has led to a reduction in genetic diversity within crops, as only a narrow range of diversity was selected by early farmers - an effect commonly described as the domestication bottleneck. But breeders need all the genetic diversity they can get their hands on to improve the worldRSQUOs crops. Many are therefore keen to reach back through the domestication bottleneck to make use of the diversity that can still be found in the ancestors and wild relatives of crops (CWR). These taxa are increasingly recognized as being of key importance to breeding efforts in general, and those that aim to help adapt agriculture to climate change in particular. The list of possible traits that could be used to enhance crop adaptation to the worldRSQUOs new climates is extensive, including everything from enhanced root growth to faster grain filling. What reasons are there to think that such traits can be found in the generally unimpressive-looking wild and weedy plants that are the closest relatives of crops? We know that many CWRs grow in conditions of climate and soil that are marginal for the crop. We also know that many show marked differences from the crop, such as perenniality, fleshy roots and distinct phenology. Some of these are likely to be of importance for adaptation. Here we explore how wild plant biodiversity may turn out to be the crucial tool in our armoury to battle the perfect storm of ever-increasing world population, high input costs and a rapidly changing climate.