Assessing yield and yield stability of remnant populations of Cenchrus ciliaris L. in arid Tunisia: developing a blueprint for initiating native seed production

Abstract

Native seed needs to be sourced locally yet contain ample genetic variation. A blueprint is developed for assembling and assessing native plant material at one eco-geographical site prior to seed multiplication for restoring degraded drylands of North Africa. To satisfy the 'local yet ample' criterion, the feasibility of selecting a limited number of high-yielding genotypes within one starter collection of Cenchrus ciliaris L. in Presaharian Tunisia (100-200 mm annual rainfall) was tested and compared to outcomes with similar work on its ecological complement, Stipa lagascae R. & Sch. Results showed that a limited number of high-yielding genotypes can easily produce quality native seed because of the high genetic diversity of the starter material. Results also showed that there was a high potential to increase the rain-use efficiency of degraded drylands using this seed. Seven ground rules are suggested when building the starter collection: (i) carefully delimit the region for sourcing seed; (ii) work with individual plants; (iii) carefully choose the collection site; (iv) replicate plant material as much as is feasible; (v) match evaluation methods to resource constraints; (vi) wait for conditions of maximum resource availability before culling; and (vii) apply a two-tiered selection strategy.

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

“…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).…”

“…Although several studies of the morphological variability of C. ciliaris have been conducted (M'seddi et al 2002, 2004bMnif et al 2003Mnif et al , 2005aArshad et al 2007;Jorge et al 2008;Visser et al 2008;Arshadullah et al 2011), few comparisons between populations and studies of the heritable nature of important traits have been undertaken. In one rare study, the progeny from different populations was tested.…”

“…Multiple morphometric variables mainly linked to productivity (tiller number, spike number and aboveground biomass) were examined at the vegetative and reproductive stages. These measurements were quantitative, while previous studies concerning the phenotypic diversity of C. ciliaris were merely semiquantitative, using a visual scoring method (M'seddi et al 2002;Visser et al 2008).…”

“…According to Visser et al (2008), dealing with seed collection strategies for restoration projects of degraded arid areas, it would be more appropriate to use a seed mixture of native genotypes of C. ciliaris than to use cultivars composed of a single genotype. Whalley et al (2013) made a similar recommendation for restoration using Australian native grasses, which are predominantly inbreeding using a range of different mechanisms.…”

Ecological effects on the flowering phenology of Cenchrus ciliaris L. collections from the arid and semiarid lands of Kenya

“…This has led to the selection of true breeding genotypes from ecotypes that are highly variable in traits of both ecological and agronomic importance due to adaptation to multiple environments (Boonman, 1993;Arshad, 2007). The species has been evaluated in various studies for reseeding potential (Mnene, 2006;Kirwa et al, 2010), allelopathic effects (Kirwa et al, 2012), performance in mixtures (Mganga et al,, 2010a) and seed and herbage yields (M'seddi, 2005;Visser et al, 2008). Studies on morphological characterization of accessions of C. ciliaris resulted in various groupings particularly using variation in plant size and flowering time (Pengelly et al, 1992;Jorge et al, 2008).…”