Crop Biotech Update

Greenhouse Assays Measure Responses of Synthetic Hexaploid Wheat to Tan Spot

May 7, 2010

Decreased tillage, together with limited use of rotation crops have led to increase in the severity of the tan spot of winter wheat (Triticum aestivum L.) in the southern Great Plains. Though genetic resistance helps control the pest, only a few commercial lines are available in the south Great Plains which has highly effective resistance. This paved the way to a search for the germplasm or genetic resources with resistance to tan spot through greenhouse experiment.

Jana F. Morris of the Oklahoma State University and colleagues conducted the greenhouse assay to identify new sources of resistance, evaluate the differences in physical characteristics in the tan spot reaction and confirm the quantitative visual assay using digital techniques. Results showed that more than 50% of the 94 synthetic hexaploid wheat samples assayed exhibited percentage leaf infection close to the percentage of the resistant check. Visual estimates were also correlated with the digital estimates. Based on the assay results, a significant amount of genetic resources may be removed for unfavorable susceptibility to tan spot.

The abstract of this study is available at