Tarbiat Modares University Journal of Crop Protection 2251-9041 7 2 2018 06 01 Genetic diversity and pathogenic variability among Cercospora beticola Sacc. isolates causing leaf spot of sugar beet in Iran  تنوع ژنتیکی و بیماریزایی جدایه‌های Sacc. Cercospora beticola عامل لکه برگی چغندرقند در ایران  207 217 1386 10.48311/jcp.2018.1386 EN Seyed Bagher Mahmoudi Sugar Beet Seed Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran. Maryam Saffarian Abbaszadeh Clemson University, South Carolina, USA. Saeed Abbasi Department of Plant Protection, College of Agriculture, Razi University, Kermanshah, Iran. Reza Farrokhinejad Department of Plant Protection, College of Agriculture, Shahid Chamran Universty of Ahvaz, Ahvaz, Iran. Journal Article Cercospora leaf spot caused by Cercospora beticola has a great negative impact on yield and quality of sugar beet. In the present study, pathogenic and genotypic variation of 24 C. beticola isolates collected from different regions of Iran were studied using RFLP of the Internal Transcribed Spacer (ITS-RFLP), and Random Amplified Polymorphic DNA (RAPD-PCR). Pathogenic variability and genotype × isolate interaction were evaluated in greenhouse experiments on five sugar beet cultivars (FD0018, HM1836, Puma, Eudora and Monatuna). All of the 24 isolates tested were found to be pathogenic on the cultivars with significant variation in disease severity. Results of RAPD analysis showed wide DNA polymorphism among the Iranian C. beticola isolates. Restriction pattern of the internal transcribed spacer of rDNA (ITS1-5.8-ITS4) was studied using three restriction endonucleases: EcoR1, Taq1, and Busr1. The length of undigested DNA fragment of all isolates was estimated to be 500bp without rDNA polymorphism after digestion with EcoR1 (280, 270 bp), Taq1 (330 bp) and Busr1 (240, 220, 90 bp). RAPD and ITS-RFLP markers showed the highest level of genetic diversity which confirms the variation in C. beticola detection. https://jcp.modares.ac.ir/article_1386_363763e5c3dc3a68b399058c34aecf2c.pdf