North American Crop Wild Relatives
AbstractSampling seed from natural populations of crop wild relatives requires choice of the locations and the amount of seed to sample. While this may seem like a simple choice, in fact careful planning of a collector’s sampling strategy is needed to ensure that a crop wild collection will contain high genetic variation, which is in turn needed for high potential for breeding or selection. Here we first describe the different conservation targets and intensities at which a collector might sample. We then review research on the appropriate number of populations, plants, and seeds to collect, and we review different methodologies available for helping to make these decisions. We suggest that samplers reconsider the long-standing minimum of 50 samples per population, as this will be insufficient in some cases. We explain that the optimal minimum number of populations, samples, and seeds can be determined with modeling approaches (niche modeling, a genetic survey, or simulations) that use knowledge of a species’ inherent traits (e.g., outcrossing rates) and geographic distribution. Lastly, we review some practical aspects of sampling, including the need to return to the source population to collect seed due to genetic change over time and the need to collect additional seed (sometimes 10 times as much seed) to account for loss of seed during storage and use. We also emphasize the utility of collecting abundant spatial and environmental data during seed sampling, as well as considering how samples will be used for accompanying genetic analyses, in order to make ex situ collections useful for research and breeding for many years to come.
Alternate TitleChapter: Sampling Wild Species to Conserve Genetic Diversity