Variation in virulence of cereal cyst nematode populations from North Africa and Asia

Eight populations of Heterodera avenae, H. filipjevi and H. latipons were tested in Petri dishes with six cereal differentials of the International Test Assortment and a set of resistant genotypes of wheats. Ratios of white females/juveniles inoculated were equivalent to those obtained previously in tubes and pots and confirmed the validity of the miniaturised technique used to study the virulence/resistance relationships of these nematodes and cereals. The populations were differentiated by virulence to barley differentials and a new group of pathotypes of H. avenae originating from Algeria was established. Differentiation among H. avenae populations from North Africa and West Asia was clearly demonstrated by their (a)virulence to the gene Cre1 in Triticum aestivum cv. Loros. As previously observed, cultivated and wild oats were poor hosts for Mediterranean populations of H. avenae, but contrasting host responses were observed for a physiological winter type of oat. In addition to describing the virulence status of H. filipjevi and H. latipons populations to barley, oat and wheat differentials, these results provide information for the introduction of resistance to barley and wheat breeding programmes.