This ecogeographic approach uses a set of calculations aimed at determining how representative is a set of accessions (belonging to a cultivated species), in relation to the known presence of the crop. Current crop distribution surfaces from the Land Use and Global Environmental Change of the Department of Geography at McGill University and accessions data from these major databases: SINGER, GRIN and GBIF were used. Still, significant gaps regarding geographic information are found in these latter databases. As an example, following graph shows the proportion of georreferenced accessions for each of the cultivated species included in the GapAnalysis.
Due to this lack of reliable location data (common situation for very old samples), the application of the method and its conclusions might be limited to the extent at which geographic information can be used to characterize the set of accessions under analysis.
Following analyses are based in an ecogeographic approach for assessing gaps in landraces ex situ collections of 14 major food crops.