New insights into the polyploid complex Cenchrus ciliaris L. (Poaceae) show its capacity for gene flow and recombination processes despite its apomictic nature

Abstract

International audienceno abstrac

The polyploid nature of Cenchrus ciliaris L. (Poaceae) has been overlooked: new insights for the conservation and invasion biology of this species – a review

“…In these studies the phenotypic variables measured showed considerable differences among populations of C. ciliaris and among maternal parent plants within the same population (Kharrat-Souissi et al 2011). This was a novel result compared with previous studies on the morphological variability of C. ciliaris.…”

“…Considering the ecological interest offered by C. ciliaris: drought tolerance (Bhatt et al 2007; De La Barrera and Castellanos 2007;Kharrat-Souissi et al 2012a), high fodder production and nutritive value to livestock (Kharrat-Souissi et al 2010;Arshadullah et al 2011), rapid regeneration in response to rainfall (Bose and Balakarishnan 2001), tolerance of heavy grazing (M'seddi et al 2004a) and soil stabilisation abilities because of a deep root system (Chaieb et al 1996;Mnif and Chaieb 2009), the persistence of this species in its native range in arid ecosystems is a crucial factor for restoration ecology of degraded arid rangelands. For these reasons, C. ciliaris has been the subject of numerous applied studies, which have focussed on its phenotypic polymorphism, its ecological significance (M'seddi et al 2002;Arshad et al 2007;Jorge et al 2008;Visser et al 2008;Kharrat-Souissi et al 2010;Arshadullah et al 2011), resistance to drought (Mansoor et al 2002;Mnif and Chaieb 2010;Kharrat-Souissi et al 2012a), biological invasion capacity (Friedel et al 1996;Franklin et al 2006;GutierrezOzuna et al 2009;Marshall et al 2012) and its genotypic diversity (Nisar et al 2010;Al-Soqeer 2011;Kharrat-Souissi et al 2011).…”

“…The C. ciliaris complex contains three ploidy levels including tetraploids (2n = 4x = 36), pentaploids (2n = 5x = 45) and hexaploids (2n = 6x = 54) (Fisher et al 1954;Bashaw and Hignight 1990;Kharrat-Souissi et al 2013). The high phenotypic polymorphism (Arshad et al 2007;Jorge et al 2008;Kharrat-Souissi et al 2011) in the presence of polyploidy suggests that apomixis in C. ciliaris may be facultative. The flexibility in reproductive behaviour that is frequently associated with an increase in ploidy might be highly relevant for colonising species by increasing the ability to reproduce under suboptimal conditions and allowing for asexual reproduction in the absence of suitable mates (Bessa-Gomes et al 2003).…”

“…In one rare study, the progeny from different populations was tested. Here, variability among populations, within populations and among individuals of the same offspring was examined (Kharrat-Souissi et al 2011). Multiple morphometric variables mainly linked to productivity (tiller number, spike number and aboveground biomass) were examined at the vegetative and reproductive stages.…”

“…The Rangeland Journal Kharrat-Souissi et al (2011) showed that heritable phenotypic traits mainly associated with productivity (e.g. aboveground biomass) were highly correlated: number of tillers, number of spikes, plant height and tuft diameter.…”