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Genotypic and phenotypic characterization of Stagnospora nodorum blotch of wheat in Virginia

Navjot Kaur: Virginia Tech Tidewater AREC

<div><em>Parastagnospora nodorum</em> ((Berk.) Quaedvlieg, Verkley & Crous) (teleomorph <em>Phaeosphaeria nodorum</em>) is a necrotrophic pathogen which causes Stagnospora nodorum blotch (SNB) in wheat. The fungus infects both leaves and glumes, causing significant yield loss in wheat. <em>P. nodorum</em> populations have not been well characterized in Virginia, so the objectives of this study were to 1) develop molecular markers to genotype <em>P. nodorum</em> isolates, 2) assess genetic diversity within and among pathogen populations in Virginia wheat fields, and 3) evaluate variation in fungicide sensitivity within <em>P. nodorum</em> populations. Simple sequence repeat (SSR) markers were designed by mining publically available genomic data for <em>P. nodorum</em>. Isolates were collected from 5 different wheat fields in Virginia in 2017 and genotyped with 10 SSR markers. Diversity within and among fields were compared using molecular haplotypes assembled from the molecular markers. <em>In vitro </em>assays were used to screen isolates for sensitivity to strobilurin, triazole, and SDHI fungicides. Management of SNB in wheat can be improved through the use of molecular tools to gain a better understanding of genotypic diversity and fungicide sensitivity within <em>P. nodorum</em> populations.</div>