Abstract only

Stem rust is a disease of economic importance to barley as well as wheat. The objective of this study was to determine the seedling and adult plant responses of barley accessions to Pgt race Ug99. Two hundred and eighty introductions from North America, South America, Europe, Asia and East Africa were screened for seedling response in the greenhouse and for adult plant response in the field for two seasons. Variable disease severities ranged from 0 to 70S with 40% of the germplasm showing slow disease progress. Although disease severity depended on the season, over 60% of the introductions were susceptible to race Ug99. At the seedling stage, 67% of the germplasm exhibited low infection types with no sporulating uredinia. However, lines originating from Canada, Bangladesh, England, North Dakota State University, Utah State University and Wisconsin gave infection types of 2+ to X; these types of reactions were typical of 33% of the lines. Twenty two lines (22%) that were resistant in the field constituted cultivars that had a mesothetic (X) seedling infection type. The study indicated that there is limited germplasm resistant to race Ug99 and efforts to identify and characterize new sources of resistance are imperative to prevent future losses and to maintain resistance diversity.

Global Wheat Program

English

Lucia Segura

INT2843

CIMMYT Staff Publications Collection