Genetic Characterization of Barley Net Blotch Resistance Genes.

Net blotch, caused by Pyrenophora teres f. teres, is one of the most devastating diseases of barley (Hordeum vulgare). Efficient utilization of available resistance sources is dependent upon successful characterization of genes conditioning resistance in diverse sources. Five net-blotch-resistant parents and one susceptible parent were intercrossed to identify novel resistance genes and postulate gene number and mode of inheritance. Seedling response to isolate ND89-19 was evaluated in a greenhouse test. Results indicate that the resistant spring barley lines CIho 2291 and CIho 5098 and the winter barley cv. Nomini each have single dominant genes for resistance. Resistance in CIho 5098 is governed by the same dominant gene conferring resistance in Nomini. Resistance in CIho 2291 is controlled by one dominant gene which, putatively, is the same gene conferring resistance in ND B112 but differs from the resistance genes carried by the other parents in this study. The resistance gene in Nomini or CIho 5098 could be pyramided with the resistance gene in CIho 2291 or ND B112 to enhance the durability of resistance against a wide spectrum of P. teres isolates.