Pythium delawarii--a new species isolated from soybean in Ohio.

A new species of Pythium isolated from soybean in Ohio is described. Pythium delawarii sp. nov.

Validation of consensus quantitative trait loci associated with resistance to multiple foliar pathogens of maize.

Maize production in sub-Saharan Africa incurs serious losses to epiphytotics of foliar diseases. Quantitative trait loci conditioning partial resistance (rQTL) to infection by causal agents of gray leaf spot (GLS), northern corn leaf blight (NCLB), and maize streak have been reported. Our objectives were to identify simple-sequence repeat (SSR) molecular markers linked to consensus rQTL and one recently identified rQTL associated with GLS, and to determine their suitability as tools for selection of improved host resistance.

Distribution and Pathogenic Characterization of Pyrenophora tritici-repentis and Stagonospora nodorum in Ohio.

ABSTRACT To determine the distribution of Stagonospora nodorum and Pyrenophora tritici-repentis on wheat in Ohio, flag leaves with lesions were collected from wheat-producing counties in 2002 and 2003. Counties were arbitrarily grouped into seven regions. Log-linear analysis of pathogen presence within regions indicated that the presence of S.

Heritability and Components of Resistance to Cercospora zeae-maydis Derived from Maize Inbred VO613Y.

ABSTRACT Gray leaf spot (GLS), caused by the fungus Cercospora zeae-maydis, is one of the most important foliar diseases of maize. This study was undertaken to estimate heritability of C. zeae-maydis resistance and examine the relationship between previously identified resistance loci and certain components of resistance including incubation period, lesion number, and maximum lesion length.

Reaction of Commercial Soft Red Winter Wheat Cultivars to Stagonospora nodorum in the Greenhouse and Field.

Thirteen cultivars were evaluated in the greenhouse and field for reaction to Stagonospora nodorum leaf and glume blotch. Coker 9663 exhibited consistent resistance across both greenhouse and field tests. In field plots, all cultivars tested had relatively high percentages of S.

Effects of Choline, Betaine, and Wheat Floral Extracts on Growth of Fusarium graminearum.

Fusarium head blight has been more severe when infection occurs during anthesis, indicating that floral organs may be important infection courts. Choline acetate and glycinebetaine have been extracted from wheat and reported to be growth stimulants of Fusarium graminearum. They are hypothesized to enhance infection and tissue colonization.

Evaluation of Inoculation Methods to Determine Resistance Reactions of Wheat to Fusarium graminearum.

Reliable greenhouse assays are needed to differentiate types of resistance in wheat to Fusarium graminearum. Genotypes with known field reactions were evaluated for resistance type using four greenhouse inoculation techniques. Percentage of spikelets with symptoms per spike (severity) and percentage of inoculated spikelets per spike developing symptoms were assessed 7, 10, and 14 days after inoculation (DAI).