First screening for resistance in Argentinian cultivars against Pyrenophora teres F. maculata, a recently reported pathogen in wheat

Abstract

The Pyrenophora genus involves an extremely important group of fungal plant pathogens, causing some of the most devastating disease epidemics of cereal plants worldwide. Among them, tan spot caused by Pyrenophora tritici-repentis is one of the major constraints of wheat production in Argentina. Furthermore, Pyrenophora teres F. maculata is a new recently recorded pathogen infecting leaves of wheat plants causing the spot-type of net blotch, a leaf-spotting symptom easily confused with those caused by tan spot. Most of the wheat cultivars in Argentina have been reported as moderately susceptible to P. tritici-repentis under natural infections. Concerning P. teres F. maculata, no information is available about the currently used cultivars in Argentina. Thirty wheat cultivars currently widely used in Argentina were evaluated for their reaction to one isolate of P. tritici-repentis and two isolates of P. teres F. maculata. The type of lesions occurring on plants was a reliable indicator of susceptibility or resistance of cultivars to both pathogens with artificial inoculations under pot and field conditions. Several wheat genotypes showing susceptibility or resistance to the isolates of the two pathogens tested at seedling and adult plant stages were found. This is the first report of the reaction of Argentinian cultivars to the new pathogen P. teres F. maculata in wheat. We detected that Don Mario Algarrobo, Buck SY 110 and ACA Cedro could be used as source of resistance for both pathogens at seedling and adult stages. This information is useful to improve the resistance to the disease in breeding programs.