|LESTON, NATALIE - Washington State University|
|MICKNASS, UTE - Justus-Liebig University|
|KOGEL, KARL - Justus-Liebig University|
|IMANI, JAFARGHOLI - Justus-Liebig University|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2015
Publication Date: 3/20/2016
Citation: Okubara, P.A., Leston, N., Micknass, U., Kogel, K.H., Imani, J. 2016. Rapid quantitative assessment of Rhizoctonia tolerance in roots of wheat and barley. Plant Disease. 100(3): 640-644.
Interpretive Summary: To facilitate screening for genetic resistance to Rhizoctonia in wheat and barley, we developed three rapid assays for quantifying seedling damage. The assays use low-cost materials and can be done in 3 or 7 days, compared to 14-21 days for standard assays.
Technical Abstract: Rhizoctonia solani AG8, causal agent of Rhizoctonia root rot and bare patch in dryland cereal production systems of the Pacific Northwest, USA and Australia, reduces yields in a wide range of crops. Disease is not consistently controlled by available management practices, and genetic resistance is desirable as a sustainable resource for growers. In this report, we describe three rapid and low-cost assays for R. solani AG8 resistance/tolerance in wheat and barley, with the view to facilitating screens for genetic resistance in these hosts. The first assay uses 50 mL conical centrifuge tubes containing soil infested with R. solani AG8 on a substrate of ground oats. The second assay is done by directly dipping roots of 3-d-old seedlings in infected ground oats. The third assay, applied to barley, uses whole infected oat kernels in 50 mL tubes. Symptoms are quantified on the bases of root fresh weight, total root length and root discoloration at 7 and 3 d for tube and dip assays, respectively. The assays are suitable for laboratory, growth chamber or greenhouse venues.