Regional Breeding for Wheat Stripe Rust Resistance in the Eastern United States David Marshall Plant Science Research Unit Raleigh, NC
The U.S. has the most cost-effective and plentiful food production and supply system in the world.
Stripe Rust Epidemic Years and the States with Greater than 1% Yield Loss from 1976 to 2004. % Loss Epidemic Year
Objectives: • Identify stripe rust resistance/susceptibility in Eastern U.S. wheat cultivars, elite lines, and other germplasm. • Identify the gene or genes involved resistance. • Introgress stripe rust resistance into elite lines having regional/local adaptation. • Distribute populations and fixed lines to cooperators.
Protocol: • Established the Uniform Eastern Wheat Stripe Rust Nursery. In 2005-06, had up to 20 entries from State breeding programs in FL, GA, NC, VA, MD, NY, MI, MO, IL, IN, KY, AR, and LA; private breeding programs – Westbred, AgriPro-Coker, and Genesis; and USDA/ARS. • Seedling screening in Raleigh, NC. • Field screening in Plains and Griffin, GA; Kinston, NC; Baton Rouge and Winnsboro, LA; Fayetteville, AR; San Antonio, TX, Pullman and Mt. Vernon, WA.
Identified 102 lines with resistance better than the "resistant" check (Pioneer 26R61). Infection types less than '3' and severities less than 18%. Identified adult-plant resistance in at least 8 lines:
Several lines had combined stripe rust, leaf rust and powdery mildew resistance.
Regional Breeding scheme for introducing resistant sources: A. Backcross-Bulk (minor genes) 1. Several resistant sources x Adapted type 2. Backcross to Adapted type 3. Select in BC1 through F3 for low terminal severities B. Accelerated Population Development for major genes 1. Resistant source x Adapted type (crosses made in February) 2. F1 planted in NZ in May, F2 in NC in Nov, F3 in NZ in June, F4 in in Nov.