Genetic stability of net x spot hybrid progeny of the barley pathogen Pyrenophora teres

Hybrid progeny produced from a mating between a net- and a spot-type isolate of the barley net blotch pathogen Pyrenophora teres were screened to assess their viability and genetic stability. Progeny (F-1) inoculated onto seedlings of the barley cultivars Stirling ( highly susceptible to net-, and slightly susceptible to spot-type isolates), B87/14 and Clipper ( only susceptible to spot-type isolates) produced jagged-type symptoms on all cultivars. When cultures (F1-1) isolated from leaves inoculated with F-1 cultures were inoculated onto these cultivars, they produced similar symptoms. F1-2 cultures isolated from F1-1 infections also produced similar symptoms. RAPDs produced on all isolates of F1-1 and F1-2 progeny revealed identical profiles to those obtained for F-1 isolates. Molecular and infection data indicated that jagged-type hybrid progeny of this net x spot mating retained their virulence and fertility over time, and were genetically stable after two cycles of inoculation, mitosis and re-isolation. Hybridisation between net- and spot-type isolates of P. teres may, therefore, play a significant role in net blotch epidemiology in barley-growing areas.