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Pyrenophora teres is an economically important pathogen of barley worldwide causing net blotch diseases. In this study, the frequency and mating-type alleles's distribution as well as genetic diversity of P. teres were assessed on micro-spatial scale and also on macro-geographical scale to find out whether a sexual cycle is possible within its Iranian populations. A multiplex PCR assay was developed for simultaneous identification and recognition of P. teres f. teres and P. teres f. maculata and to screen their mating-type alleles. 118 isolates of P. teres were procured from barley fields of East Azerbaijan province during 2017-2018. Among 89 isolates of P. teres f. teres examined, 39 isolates were found as MAT1-1 and 50 isolates were found to be MAT1-2.Among 29 isolates of P. teres f. maculata examined, 17 isolates were found as MAT1-1 and 12 isolates were found to be MAT1-2 with the dominancy belonging to MAT1-1.Nearly same mating-type alleles distribution within and between various populations of P. teres f. teres (1:1 ratio; χ 2 = 1.36) and P. teres f. maculata (1:1 ratio; χ 2 = 0.862) was observed. Genetic diversity assessment of 118 P. teres isolates was carried out through inter-simple sequence repeat (ISSR) analysis and results revealed that there was 70.83% and 63.89% polymorphism among the isolates of P. teres f. teres and P. teres f. maculata, respectively. No relation was observed between the isolates and their mating as well as geographical type. Among collected isolates (89 P. teres f. teres and 29 P. teres f. maculata isolates), the gene diversity was generally similar (h = 0.280 and h = 0.238 for P. teres f. teres and P. teres f. maculata, respectively). Based on our findings and referring to the prior data on the structure of P. teres population, we conclude that in the majority of tested areas, this fungal species might have the potential to undergo regular sexual recombination cycles.

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Leaf stripe disease caused by Pyrenophora graminea is an economically significant disease of cultivated barley worldwide, including Iran. Considering economic impact of this disease on barley industry in Iran, in this study genetic diversity of P. graminea populations mainly collected from barley (229 isolates) in different regions of East Azerbaijan Province was examined using ISSR and RAPD molecular markers. The average polymorphic information content (PIC) values for ISSR and RAPD were 0.28 in both markers, and a significant correlation was observed between ISSR and RAPD data (r = .78, p < .05). No clear clustering was found within P. graminea populations in relation to their geographical origins. Applying the unweighted pair group method with arithmetic mean (UPGMA) procedure and principal coordinates analysis (PCoA) revealed no obvious clustering of isolates based on geographic region. Totally, gene diversity of 0.2 was noticed among P. graminea isolates. High level of genetic differentiation (PhiPT = 0.257; p ≤ .001), with 74% of the genetic variation occurring within populations and 26% occurring among populations, indicated the existence of population differentiation. In addition, a moderate amount of gene flow (Nm = 1.1985) was found between populations. Information obtained from this study may be beneficial to design and improve management strategies such as breeding resistant barley varieties to leaf stripe disease.