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ARS Home » Pacific West Area » Pullman, Washington » Plant Germplasm Introduction and Testing Research » Research » Publications at this Location » Publication #121481


item Dugan, Frank

Submitted to: Mycotaxon
Publication Type: Abstract Only
Publication Acceptance Date: 1/1/2002
Publication Date: 5/1/2002
Citation: Dugan, F.M., Peever, T.L. 2002. Morphological and cultural differentiation of described species of alternaria from poaceae. Mycotaxon. 83:229-264.

Interpretive Summary: Alternaria is a genus of microscopic fungi, some of which are saprophytes and some of which are plant pathogens. Some Alternaria species are prolific producers of mycotoxins and other species are not. Alternaria species are commonly seed-borne. Graminicolous (infecting grass family hosts) species of Alternaria include agents of the minor diseases black point and sooty mold of cereals, as well as major diseases stack burn of rice and leaf blight of wheat. The latter disease is caused by an Alternaria species not yet known from the USA, but now reported to be in Mexico. This research will provide plant pathologists and inspection officials a set of keys and descriptions to the important graminicolous species of Alternaria. Such keys are presently incomplete or lacking.

Technical Abstract: Twelve graminicolous species of Alternaria are described, illustrated and keyed by cultural and morphological characters. Ex-type, authentic or representative living material of Alternaria alternata, A. cetera, A. infectoria, A. longissima, A. metachromatica, A. oregonensis, A. padwickii, A. tenuissima, A. tritcicola, A. triticimaculans, and A. triticina furnish the basis for descriptions and illustrations, as do type or authentic exsiccati of A. longissima, A. padwickii and A. saparva. Sporulation and other characters in available cultures ad/or exsiccati of A. graminum, A peglioni, and A. maritima were insufficient for construction of reliable descriptions. Five names are listed for well characterized species that are of only incidental occurrence on Poaceae; an additional four names are listed for which material was unavailable. Strains of small spored, chain forming Alternaria spp. isolated from uncultivated grasses in Washington and Idaho, or from USDA-ARS seed accessions, frequently conformed to A. infectoria or A. tenuissima but only infrequently to A. alternata. No strains in precise conformity to A. alternata sensu Simmons were recovered. Not all strains conformed to descriptions derived from ex-type, authentic or representative material. Results from these morphological and cultural studies will be treated as hypotheses for work based on molecular methods.