Population Genetic Diversity of 1000 Wild Chickpea Accessions

Chickpea (Cicer arietinum) is the second most widely grown pulse legume in the world. As with many crop species, however, it exhibits narrow genetic variability. This lost of standing variation limits its ability to adapt to extremes in the natural environment. Population development in chickpea would be greatly improved by introducing adaptive alleles from wild relatives into the chickpea germplasm collection. Effective use of wild germplasms will require systematic understanding of the populations. We sampled wild chickpea throughout its ancestral range in Turkey and characterized these samples to understand its diversity. Analysis of population structure resolved the collection into its component species: C. arietinum (cultivated), C. reticulatum, and C. echinospermum. Subsequent analysis of each species separately resolved 8 well-supported populations among C. reticulatum accessions, 4 populations among C. echinospermum, and 2 populations among cultivated C. arietinum. Pairwise diversity analyses and calculation of genetic differentiation by means of Nei’s genetic distance and Fst support these divisions and reveal that C. reticulatum is considerably more diverse than either C. arietinum or C. echinospermum.