Genetic studies on net blotch resistance in a barley cross

An investigation was initiated to study the genetics of resistance to three isolates of Pyrenophora teres (WRS102, WRS858, and WRS857), which have been routinely used for screening for net blotch resistance in Canada. The F-1, F-2, and doubled-haploid lines were derived from a Leger/CI9831 cross of barley (Hordeum vulgare L.). These materials, along F with their parents, were inoculated with each of the three isolates at the three-leaf stage in growth chambers. Results showed that resistance to WRS102 was controlled by three recessive genes, resistance to WRS858 by one recessive gene, and resistance to WRS857 by either one dominant gene or two complementary genes. One of the WRS102-resistance genes appeared to be on chromosome 2 and another linked to the WRS858-resistance gene. Resistance to these three isolates was not associated with awn type, esterase 1, and esterase 5. Selection for resistance to WRS102 and WRS858 would be more effective than selection for resistance to WRS857 in a conventional breeding program.