Morphological adaptation toLolium rigidumGaudin to different conditions of the Medeterranean semi-arid environment

A field evaluation, aimed at comparing several morphological traits of one cultivar ("Wimmera") and a Sardinian genotype ("Nurra") of annual ryegrass, was carried out in Northern Sardinia. The two accessions were compared over two years in a field experiment, following the UPOV rules for the identification of new cultivars. The distinctness of "Nurra" for flag leaf, tiller, spike and spikelet length was clearly demonstrated. Also, some "Nurra" plant adjustments in water-limited environmental conditions in late spring (elongation of spikelets and awns, late heading, increase of awn presence, higher fertility) seem to be an adaptive response of a drought-tolerant morphotype. The results of this experiment contribute to the agronomic valorisation of "Nurra" ryegrass as a valid drought-tolerant material suitable for introduction into the semi-arid pasture seed market.