What wild species is the closest evolutionary relative of the chickpea used in hummus?

The closest evolutionary relative of the chickpea is Cicer reticulatum.

Cicer reticulatum is a wild legume native to a small area of southeastern Turkey and nearby Syria. It is regarded as the wild progenitor of the cultivated chickpea, Cicer arietinum, which is the species used in foods such as hummus. The two species are closely compatible genetically, and researchers have produced fertile hybrids between them.

This relationship helps explain how chickpeas were domesticated in the Fertile Crescent. Archaeological evidence from sites in modern Syria records both cultivated chickpeas and wild C. reticulatum among early agricultural remains. Domestication selected plants with larger, more palatable seeds and more useful ripening and pod traits.

Cicer echinospermum is a common source of confusion because it is also closely related and can hybridize with chickpeas. However, hybrids involving it are generally less fertile. That distinction makes C. reticulatum the accepted closest relative and direct wild ancestor, rather than merely one of several related wild legumes.