Barbara Christ

Professor of Plant Pathology

407 Buckhout Laboratory
University Park, PA 16802

Phone: 814-863-2068

Email: ebf@psu.edu

Education:

B.S.: Plant Science, Pennsyvania State University
M.S., Plant Pathology, University of Minnesota
Ph.D., Botany, University of British Columbia

Research Interests:

Breeding potatoes with disease resistance, examination of pathogen variability and epidemiology of potato diseases

Program Interests:

Little is known about the genetics of disease resistance in potatoes and virulence in potato pathogens. The first research goal in my project is to study the inheritance of disease resistance to early and late blight. We have developed methods to characterize resistance in potatoes to early blight and have determined heritability of resistance in one population of potatoes. We are now examining the heritability of non-specific resistance to late blight. It is our goal to find markers (RFLP and resistance gene probes) to determine where the resistance genes are located and then, using marker-based selection, to accumulate the genes into one genetic background. Even less is known about the pathogen populations. We have yet to find ways of identifying genes in the pathogen and find markers that are closely linked to virulence genes. We are currently examining population variability of both early and late blight.

Our second goal is to document the entire life cycle of the powdery scab organism and develop methods to detect this organism. Very little is known about this organism. Our research focuses on basic epidemiological studies to determine the environmental conditions conducive to disease development. We are also characterizing the disease reaction in hopes of developing disease resistant cultivars. Little is known about alternative hosts. First we need to develop a detection technique to quantify inoculum and/or identify disease on alternative hosts. Verification of disease on any host is done on the presence of resting spores. Not all hosts will allow the resting spores to develop. There are no adequate control measures for this disease, and disease resistance may be the only alternative.

A third research goal is the development of potato germ plasm and new cultivars for Pennsylvania. Potato germ plasm is evaluated for yield, adaptability to specific environmental conditions, disease resistance, processing traits such as suitability for chipping, and culinary traits for French frying, baking, and boiling. We continue to release new cultivars that are suitable for Pennsylvania production.

The fourth goal is to develop a comprehensive integrated pest management system for potatoes. We have incorporated a disease resistance factor into a forecasting scheme to reduce the number of fungicides applied to resistant potato cultivars. We continue to explore novel methods for gathering and disseminating weather data and information on probability of disease occurrence.

Publications:

Weisz, R., Z. Smilowitz, and B. Christ. 1994. Distance, rotation and border crops effect on Colorado Potato Beetle (Coleoptera: Chrysomelidae) colonization and population density and early blight (Alternaria solani) severity in rotated potato fields. Journal of Economic Entomology 87:723-729.

Weisz, R., M. Saunders, Z. Smilowitz, H. Huang, and B. Christ. 1994. Knowledge-based reasoning in integrated resistance management: The Colorado potato beetle (Coleoptera: Chrysomelidae). Journal of Economic Entomology 87:1384-1399.

Haynes, K. G., D. H. Lambert, B. J. Christ, D. P. Weingartner, D. S., Douches, J. E., Backlund, G. Secor, W. Fry, and W. Stevenson. 1998. Phenotypic stability of resistance to late blight in potato clones evaluated at eight sites in the United States. Amer. J. Potato Research 75:211-217.

Weir, T., D. R. Huff, B. J. Christ, and C. P. Romaine. 1998. RAPD-PCR analysis of genetic variation in populations of Alternaria solani and Alternaria alternata from potato and tomato. Mycologia 90:813-821.

Haynes, K. G. and B. J. Christ. 1999. Heritability of resistance to foliar late blight in a diploid hybrid potato population of Solanum phureja X S. stenotomum . Plant Breeding 118:431-434.

Christ, B. J. and K. G. Haynes. 2001. Inheritance of resistance to early blight disease in a diploid potato population. Plant Breeding 120:169-172.

Assigned Responsibilities:

Dr. Christ currently has a 75% research and 25% teaching appointment within the Department of Plant Pathology. Dr. Christ was hired to perform research in plant breeding in relation to disease resistance within potato. Her initial specific responsibilities were: the development and evaluation of potato germplasm with emphasis on disease resistance and high quality, to serve as a liaison between the department and the Pennsylvania potato industry, and to develop a research program in the area of disease resistance emphasizing genetic and/or epidemiological approaches. Her teaching responsibilities were to be in the area of her research emphasis. These responsibilities have evolved over the course of her employment.

Dr. Christ's current assigned research responsibilities are:
1) Develop new potato varieties with adaptation to Pennsylvania production and marketing needs,
2) Explore disease resistance in potatoes and incorporate through traditional breeding into commercial varieties,
3) Determine the ecology and genetics of potato pathogens,
4) Develop improved disease forecasting methods and integrated pest management practices,
5) Evaluate new chemical control methods for potato diseases.

Dr. Christ is expected to maintain the support for her breeding program through extramural funding from state and national sources. Dr. Christ is also expected to serve as a liaison between the department and the potato industry and to participate in grower and industry meetings at the state and national levels, including the Pennsylvania Potato Research Board.
Dr. Christ's current instructional responsibilities include both graduate and undergraduate education through formal classroom instruction, the direct supervision of graduate student thesis research and undergraduate special independent research topics, and service on graduate student thesis committees. She is responsible for co-instructing (greater than 50%) PPATH 405-Concepts of Plant Pathology, PPATH 560-Principles of Plant Pathology, PPATH 426-Plant Pathogenic Fungi, PPATH 543-Pathogen Variation and Host Resistance, and PPATH 597-Fungal Genetics and PPATH 590-Colloquium. Her teaching emphasis is genetics of fungi and plants, disease resistance breeding and genetics, and management of potato diseases.