36 SEED TESTING INTERNATIONAL www.seedtest.org RULES DEVELOPMENT • Validation Study for Detection of Fusarium Species on Cereal Seeds Le Daré, L.1, Sérandat, I.1, McEwan, M.2, Brodal, G.3, Udnes Aamot, H.3, Isaksen, B.4 and Alberti, I.5 1GEVES, Beaucouzé, France 2SASA, Edinburgh, UK 3NIBIO, Ås, Norway 4KIMEN, Ås, Norway 5CREA – CI, Rovigo, Italy THE SCOPE OF THE PRESENT STUDY WAS TO INTRODUCE A VALIDATED METHOD FOR THE DETECTION OF FUSARIUM SPECIES IN CEREAL SEEDS into Chapter 7 of the International Rules for Seed Testing (ISTA Rules). The validation of the method was conducted according to the validation criteria described in the document ‘TCOM-P-10- Validation method and results of CTs, version 2’. The aim of this validation was to provide a testing method for the detection of Fusarium species infecting the cereals wheat, barley and oat. The performance criteria were determined and evaluated and a comparative test (CT) with seven experienced laboratories was organised. The validation data was brought together in a validation report. This report was reviewed and approved by two ISTA technical reviewers, appointed by the ISTA Seed Health Committee: Ruud Barnhoorn and Marian McEwan. A statistical review was carried out by Jean-Louis Laffont of the ISTA Statistics Committee. Introduction Fusarium head blight (FHB) complex is mainly caused by several Fusarium species and is considered to be one of the most important diseases in cereals worldwide. The disease may result in significant yield losses and poor seed quality. Several of these Fusarium species can produce toxic secondary metabolites (mycotoxins) (Desjardins, 2006) that can reduce the use of the grain for human and/or animal consumption. For example, F. graminearum, one of the most aggressive pathogens of FHB and producer of the important mycotoxin deoxynivalenol (DON), was ranked number four in an international nomination of the top ten most economically important fungal pathogens (Dean et al., 2012). When plated on different media, Fusarium species can present notoriously different phenotypes. It is therefore important to standardise the method and the media used within the laboratory and to ensure its make-up is consistent. Depending on the level of expertise of the laboratories, and for some Fusarium for which it is not possible to distinguish two different species based on the morphological criteria, the result can be given in species, complex or Fusarium sp. level (Fig. 1). The Seed Health Committee decided to carry out a validation study for detection of Fusarium spp. on cereal seeds, based on the ISTA method 7-022 for detection of Microdochium spp. on wheat (ISTA, 2020). Figure 1. Process flow diagram explaining the steps and decisions for the detection of Fusarium spp. by plating on media and morphological identification (MA = malt agar, PDA = potato dextrose agar, SNA = spezieller nährstoffarmer agar, CLA = carnation leaf-piece agar); *Fusarium reporting results can be expressed as genus, part of a complex or as species level
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