Emeritus Professor of Botany and Plant Pathology

Purdue University
Botany and Plant Pathology, Lilly Hall
915 West State Street
West Lafayette, IN 47907-2054

Retired: June 30, 2008

Area: Field crop diseases—epidemiology and management of diseases of small grains, soybean, and corn; disease resistance. Extension specialist for field crop diseases

Education

Ph.D., Oregon State University, Botany and Plant Pathology

Research Interests

Genetically conferred disease resistance is an effective and economical means of disease control and has been used for many years in cereal crops as the main methods of control. However, resistance to rusts has often proven to be ephemeral because of the ability of the pathogens to evolve new biotypes that can circumvent the host's genetic defenses.

My research concerns "slow-rusting", resistance that appears to be durable. We have quantified its expression, investigated its inheritance and stability toward pathogen variation, and are developing means of utilizing this resistance in a plant breeding program. We have found that slow leaf-rusting in wheat is a partial resistance which does not completely prevent reproduction of the pathogen on the host plant, but retards the rate of reproduction to such an extent that the pathogen population cannot reach damaging levels in the host population (the field) before th host ripens naturally. Slow rusting is analogous to the IPM concept in pesticide use that strives to keep pathogen and pest populations to manageable levels without trying for extermination. We consistently find that it is conditioned by the interaction of a few (usually two to four) partially recessive genes.

We also devote considerable effort to Septoria blights and Fusarium head blight of wheat. We are studying the genetics of resistance and exploring the effect of weather on development of epidemics with the goal of creating predictive models.

Teaching

Formal teaching includes two graduate level courses, "Plant Disease Epidemiology" and "Genetics of Host-Parasite Interaction", and one undergraduate course, "Fundamentals of Plant Classification." I also participate in two team-taught courses -- a graduate level course in principles of plant pathology and a course in plant disease management.

Selected Publications

Xu X, Bai GH, Carver BF, Shaner GE, Hunger RM. 2006. Molecular characterization of a powdery mildew resistance gene in wheat cultivar Suwon 92. Phytopathology 96(5):496-500.

Lehman JS, Hanson KA, Shaner G. 2005. Relationship among genes conferring partial resistance to leaf rust (Puccinia triticina) in wheat lines CI 13227 and L-574-1. Phytopathology. 95(2):198-205.

Xu XY. Bai GH. Carver BF.  Shaner GE. Hunger RM. 2005. Mapping of QTLs prolonging the latent period of Puccinia triticina infection in wheat. Theoretical & Applied Genetics. 110(2):244-251.

Xu XY. Bai GH. Carver BF.  Shaner GE. Hunger RM. 2005. Molecular characterization of slow leaf-rusting resistance in wheat. Crop Sci. 45(2):758-765.

Yang J, Bai G, Shaner GE. 2005. Novel quantitative trait loci (QTL) for Fusarium head blight resistance in wheat cultivar Chokwang. TAG. 111:1571-1579.

Xu X, Bai GH, Carver BF, Shaner GE. 2005. A QTL for early heading in wheat cultivar Suwon 92. Euphytica 146:233-237.

Bai G, Shaner G. 2004. Management and resistance in wheat and barley to Fusarium head blight. Annu. Rev. Phytopathol. 42:135-161.

Robinson P, Edwards J, Kommedahl T, Patrias K, Shaner G, Shirley S, Wilbur R. 2006. Scientific Style and Format, 7th edition. Reston VA, Council of Science Editors and Rockefeller University Press.

Sharma H, Ohm H, Shaner G. 2004. Resistance to barley yellow dwarf virus, powdery mildew and leaf rust in wheat ´ Thinopyrum backcrosses. Phytoprotection. 85:27-32.