Crop Wild Relatives of the United States

a blog about their conservation and use

Next Steps

Next steps toward a national CWR conservation strategy

We are working to gather occurrence data for U.S. crop wild relatives (CWR) from herbaria, genebanks and other sources for the priority taxa. Data has been collected from online databases (e.g., GBIF), crop researcher collaborations, herbarium (e.g., PNWH) and genebank databases (e.g., GRIN), and via visits to selected herbaria.

The occurrence data are being used to create “potential distribution models” for CWR, which include known occurrence locations as well as surrounding areas with similar climatic and edaphic (soil) characteristics. A“gap analysis” method1,2 is used to compare these potential distributions to the extent to which the species have already been collected and conserved in genebanks. The potential distributions are also compared with established protected areas in the United States in order to determine the current extent of conservation of crop wild relatives in situ.


The results of the gap analysis form the basis for a prioritization of taxa for further conservation action, including the identification of the highest priority locations for the most efficient collecting for ex situ conservation as well as for the establishment of active management programs for CWR within protected areas.

1Maxted N, Dulloo E, Ford-Lloyd BV, Iriondo JM, and Jarvis A (2008) Gap analysis: a tool for complementary genetic conservation assessment. Diversity and Distributions 14 (6): 1018-1030.
2Ramírez-Villegas J, Khoury C, Jarvis A, Debouck DG and Guarino L (2010) A Gap Analysis Methodology for Collecting Crop Genepools: A Case Study with Phaseolus Beans. PLoS ONE 5(10), e1349.
Maps: potential distribution model and collecting gaps maps for willow-leaf sunflower (Helianthus salicifolius A. Dietr.) by C. C. Sosa, adapted from Kantar MB, Sosa CC, Khoury CK, Castañeda-Álvarez NP, Achicanoy HA, Bernau V, Kane N, Marek L, Sieler G, and Rieseberg LH (2015). Ecogeography and utility to plant breeding of the crop wild relatives of sunflower (Helianthus annuus L.). Frontiers in Plant Science 6: 841.