Aboveground phytomass productivity and morphological variability of Tunisian accessions of Cenchrus ciliaris L.

This study assessed the aboveground aerial phytomass produced by 47 accessions of Cenchrus ciliaris L. locally collected in the arid zone of Tunisia and classified into six eco-geographic groups. The extent of genetic variation in five morphologic parameters was examined. Correlations among all parameters were also analysed. For three years, phytomass of these accessions was cut and measured for three cutting periods characterised by different rainfall features. In 1998 the mean of the phytomass productivity was 199.1g DM (Dry Matter) plant–1. The productivity in 1999 was 81.0g DM plant–1, but in 2000 the productivity was only 21.6g DM plant–1. Positive correlations were found between dry matter and all morphological parameters, especially tuft diameter (r = 0.670) and tuft height (r = 0.637). Principal components analysis was carried out on all variables. For both dry matter and phenology, individuals differentiated strongly, but irrespective of their accession or eco-geographic origin.