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POSTERS: Host resistance screening

Evaluating breeder lines for adult plant resistance to wheat leaf rust
Brian Olson - Dept. of Entomology & Plant Pathology. Robert Hunger- Dept. of Entomology & Plant Pathology, Brett Carver- Dept. of Plant & Soil Sciences

Leaf rust (LR) of wheat, caused by Puccinia triticina, is a major foliar disease of wheat with incorporation of genetic resistance being a primary approach to help manage this disease. Ideally adult plant (all-stage) resistance (APR) is used to determine lines to advance, but in dry years APR field evaluations can be poor or lacking when natural infections are low or absent. To overcome this problem, over 589 wheat breeder lines were evaluated annually for seedling and APR in the greenhouse. Seedling resistance was evaluated by inoculating eight seedlings/line using long-established procedures. APR evaluation was conducted by planting wheat seeds into button cells (8 plants/line). Three to six days after planting, germinated seeds were vernalized for 6 weeks in a cold storage room at 7° C under LED grow lights. After vernalization, plants were transplanted into containers typically used to test for seedling reaction. After 7 weeks, adult plants were inoculated with P. triticina, and LR APR was evaluated on flag, F-1, and F-2 leaves 8-11 days post inoculation. This procedure is being used to evaluate LR APR in a greenhouse environment and provides APR data in years when APR reaction in field trials is absent.