Viewpoint: Evolution of cultivated chickpea: four bottlenecks limit diversity andconstrain adaptation

Abstract

Chickpea (Cicer arietinum L.) is characterised by a different adaptation profile from the other crops of West Asian origin such as pea, barley, and wheat. In this paper we suggest that a series of four evolutionary bottlenecks occur in chickpea: (1) the scarcity and limited distribution of the wild progenitor, C. reticulatum Ladiz., (2) the founder effect associated with domestication, (3) the shift, early in the crop's history, from winter to spring sowing, and the attendant change from using rainfall as it occurs to a reliance on residual soil moisture, and (4) the replacement of locally evolving landraces by elite cultivars produced by modern plant breeding. While two of the bottlenecks are common to all species, the limited distribution of the wild progenitor and shift of cropping from utilisation of current rainfall to stored soil moisture is unique to chickpea. In this paper we suggest that in order to widen the genetic base of cultivated chickpea it is imperative to reintroduce traits from across the primary gene pool. Moreover, a comparative physiological approach to the study of adaptation among the annual wild relatives of chickpea may reveal adaptive strategies within the genus currently obscured by monomorphic loci. The poor state of the world collection of annual wild Cicer species severely constrains the implementation of both these imperatives. We suggest that an extensive collection of annual wild Cicer species, based on ecogeographic principles to maximise the probability of collecting diverse ecotypes, should provide a better understanding of the biology and adaptation in this ancient crop and lead to improved productivity.

Genetic variation of a global germplasm collection of chickpea (Cicer arietinum L.) including Italian accessions at risk of genetic erosion

“…The genetic basis of cultivated chickpea is narrow, as a consequence of several bottlenecks occurring during its evolutionary history (Abbo et al 2003). This represents a major limition for chickpea breeding (Amin and Melkamu 2014).…”

Phenological variation among Israeli populations of Cicer judaicum Boiss.

“…This narrow variation, with its consequences for adaptation of domesticated chickpea, is thought to have resulted from a series of genetic bottlenecks starting with the narrow distribution of the wild progenitor, through the domestication processes, and ending with recent replacement of landraces by modern varieties (Abbo et al 2003a). The evolutionary history of chickpea becomes even more puzzling when compared with the situation in pea and lentil, 2 contemporary domesticants of chickpea in the Neolithic Near East.…”

“…The domestication of chickpea resulted in a considerable reduction of genetic variation (Abbo et al 2003a). This narrow variation, with its consequences for adaptation of domesticated chickpea, is thought to have resulted from a series of genetic bottlenecks starting with the narrow distribution of the wild progenitor, through the domestication processes, and ending with recent replacement of landraces by modern varieties (Abbo et al 2003a).…”

“…This almost universal phenomenon largely results from the genetic bottlenecks associated with the domestication process and the subsequent selection in man-made agro-ecosystems (e.g. Ladizinsky 1985;Abbo et al 2003aAbbo et al , 2003b. The biotic and abiotic constraints to crop productivity on the one hand and the wealth of genetic variation among wild relatives of crop plants on the other hand prompted the idea that wild progenitors may serve as a valuable source of allelic variation for crop improvement (e.g.…”

Genomic tools and germplasm diversity for chickpea improvement

“…India accounts for 67.68% of this area (7.50 Mha), and 66.91% (6.54 Mt) of production followed by Pakistan (with 9.75% of area: Chickpea is traditionally grown extensively as a low input crop under receding soil moisture status with minimum management. Despite its high morphological variability, genetic variation is low (Udupa et al, 1993), probably a consequence of its monophyletic decadence from its wild progenitor C. reticulatum in the Fertile Crescent (Ladizinsky and Adler, 1976;Lev-Yadun et al, 2000;Abbo et al, 2003). The major constraints to chickpea productivity are biotic stresses like Helicoverpa pod borer and fusarium wilt, abiotic stresses like drought, extreme temperatures and salinity, apart from its poor response to better management.…”