Temporal and Spatial Variation in a Large Collection of Chickpea (Cicer arietinum) Landraces

Landraces of crops are important genetic resources, reflecting traditional cultivation practices and potential adaptation to diverse climates and agroecologies. We examine landrace diversity in chickpea, a unique crop with a wild ancestor with an extremely narrow geographic distribution in Southeastern Anatolia but landrace cultivation spanning six continents and conditions from sub-tropical South Asia and East Africa, to Mediterranean climates worldwide, and to temperate prairie conditions. By assembling a diverse collection of landraces from multiple genebanks spanning nearly century of germplasm collections and the three primary centers of diversification for chickpea, we examine changing patterns of diversity. We find little evidence of declining landrace diversity from the oldest collections in the Vavilov Institute for Research to contemporary collections. We document shifts in diversity in the center of domestication in Turkey to secondary diversification centers in South Asia and East Africa. Comparison to diversity in a recently assembled large collection of the wild relatives allows us to build a demographic model of multiple bottlenecks and diversifications impacting the diversity of chickpea.