Allelic diversity between and within three wild annual Cicer species

Abstract

Most wild Cicer species have narrow eco-geographic amplitude. Likewise, domesticated chickpea suffers from severe adaptive limitations due to its unique evolutionary history. The wild progenitor may offer only limited adaptive allelic variation for improving the chickpea crop. Therefore, there is a need to explore allelic diversity between and within annual Cicer sp. that span diverse natural habitats. Here we characterized the allelic diversity between and within wild populations of C. pinnatifidum, C. judaicum and C. cuneatum spanning most of their documented native range in Turkey, Israel and Ethiopia. Eco-geographical analysis resulted in clear separation between the collection sites of C. cuneatum in east Africa and the other two east Mediterranean species. Analysis of molecular variance shows that only 18 % of the allelic variation accounts for differences between the three species, while 34 % was contributed from difference between populations. Interestingly, most (48 %) of the allelic variation was detected among accessions within populations. PCoA analysis confirmed the independent taxonomic and indeed the genetic integrity of the two east Mediterranean sister species C. pinnatifidum and C. judaicum. Conservation of large rich populations seems a more effective strategy than the preservation of small thin populations of annual Cicer sp. Given the relatively narrow geographic range of most annual Cicer sp., accessing germplasm lines from ecologically distinct habitats emerges as the most promising strategy for the identification of useful adaptive allelic variation.