Mapping Rust Resistance and Russian Wheat Aphid Tolerance Genes in the CI10587 x Galena Population

Rossi (1), P. Hayes (1), A. Kleinhofs (2), D. Kudrna (2), D. Mornhinweg (3), C. Mundt (4), B. Steffenson (5), H. Vivar (6) Dept. of Crop Soil Science Oregon State University Corvallis, OR 97331, USA (2) Dept. of Agronomy and Soils Washington State University Pullman, WA 99164-6420, USA (3) USDA/ARS SPA Stillwater, Oklahoma 74075, USA (4) Dept. of Botany and Plant Pathology Oregon State University Corvallis, OR 97331, USA (5) Dept. of Plant Pathology North Dakota State University Fargo, ND 58105 (6) ICARDA/CIMMYT Apdo 6-641, Mexico 6, DF Mexico

Leaf rust (Puccinia hordei), stripe rust (Puccinia striiformis) and Russian Wheat Aphid (RWA, Diuraphis noxia) are biotic stresses that can negatively impact barley production. Systematic cataloging of genes conferring resistance to these stresses will facilitate efficient development of resistant varieties capable of meeting new challenges. A set of 100 doubled haploid (DH) lines derived from the cross of CI10587 x Galena will be used to map genes conferring resistance to stripe rust, leaf rust, RWA and BYDV. We mapped a qualitative resistance gene for stripe rust resistance to the long arm of chromosome 1 (7H) in this population. This is the first report of a stripe rust resistance gene at this location in barley. Stripe rust, leaf rust and BYDV genes are reported to form a cluster of linked resistance genes on chromosome 7 of wheat. We have mapped leaf rust and BYDV resistance genes to the corresponding homoeologous region of barley chromosome 1 (7H) in other populations (Cali-sib x Bowman; Shyri x Galena). We hypothesize that there is a homeologous cluster of resistance genes in wheat and barley, and in order to test this hypothesis we will determine the location of the stripe rust, leaf rust, and BYDV resistance genes in the CI 10587 x Galena population. A higher density map of the chromosome 1 (7H) region, incorporating PCR-based markers, will also facilitate characterization of stripe rust resistance gene pyramids that combine the resistance gene on chromosome 1 (7H) with resistance alleles at QTLs on chromosome 5 (1H) and 7 (5H). The phenotypic data for RWA reaction fit a two-gene model. Prior reports localize resistance genes to chromosomes 2 (2H), 3 (3H), 5 (1H) and 7 (5H). Our preliminary data indicate that one of the RWA resistance genes in this population is on the short arm of chromosome 2 (2H).