Occurrence and frequency of spot form and net form of net blotch disease of barley in Algeria

Abstract

In Algeria, barley (Hordeum vulgare L.) is the second most cultivated cereal after wheat; however, this crop is challenged by several foliar diseases. Net blotch is one of the most common diseases of barley in Algeria and is caused by the fungus Pyrenophora teres (Died.) Drechsler, which occurs in two forms: P. teres f. teres (Ptt), causing the net form (NFNB), and P.teres f. maculata (Ptm), causing the spot form (SFNB). Since the two forms are morphologically similar but genetically distinct, several PCR primer sets have been developed for their differentiation in the past. In this study, net blotch symptom types were monitored in 58 fields, through almost all cereal-growing areas in Algeria, then 212 P. teres mono-spore isolates were analyzed with respect to the occurrence of Ptt and Ptm by using two type-specific primer pairs. The results indicate that Ptt is the dominating type of net blotch in Algeria and was prevalent in almost all provinces surveyed, while Ptm was found less frequently. This is the first characterization of the Algerian net blotch population with the aim to distinguish both forms and, therefore, could contribute to a wider knowledge of the epidemics of this important plant pathogen.