by Catharina Fjelkner
Geneva, NY - Norman F. Weeden was promoted to full professor in the Department of Horticultural Sciences at Cornell University, at the New York State Agricultural Experiment Station in Geneva, NY, effective November 1, 1997.
"Weeden is an excellent cooperator and a leader as we enter the
era of bioinformatics," said Hugh C. Price,
chairman
of the horticultural department. "He has pioneered the development
of genetic mapping for peas and apples, which has broad application in
plant science. He has shown how molecular biology can be used to expand
our understanding of the plant genome."
Weeden was an early adopter of molecular techniques to develop genetic maps of horticultural crops. Today, he is a recognized specialist in the use of plant genetics. The current focus of his research is the use of molecular markers to tag genes in a number of cultivated species for marker-assisted selection purposes. A highly saturated genetic map for pea has been developed under Dr. Weeden's leadership. Markers have been identified for genes that confer or contribute to the resistance to seven viral or fungal diseases affecting peas. Weeden is currently chair of the Linkage Map Comittee of the Pisum Genetics Association that coordinates mapping efforts in pea worldwide.
"I am honored to have received this promotion," said Weeden, "and very appreciative toward Cornell and the faculty that they find my work useful and interesting." Weeden further explains that plant genetics is a hot field in biotechnology. Through DNA-analysis, one can manipulate simple inherited characteristics to help understand more complex ones. He has done most of this work studying peas "because peas represent a good model system for what I am trying to investigate, plus they are easy to grow and cross," he says.
The work Weeden is performing is of great use to commercial growers in developing more efficient crop breeding practices. One of the most important projects is to develop pea varieties tolerant to common root rot, which is caused by a fungus and considered a significant problem in the Northeast. If crops are not properly rotated, the fungus becomes abundant in the soil and will kill pea plants before they produce seed. It is extremely hard to directly screen for the various genes that influence tolerance and susceptibility, but by "tagging" these genes with easily scored DNA markers, one can make crosses, select for the markers, and develop new varieties with a high level of tolerance.
Weeden also works with disease resistance of apples. The apple Liberty contains the gene Vf which makes it resistant to scab caused by a fungus. But, such single-gene based resistance is often overcome by a few changes in the DNA of the fungus. By pyramiding different genes, one can prevent this from happening. Researchers in Weeden's laboratory have now developed markers for five of the six different genes that confer scab resistance in apples. In collaboration with Dr. Susan Brown and Dr. Herb Aldwinckle, Weeden hopes to combine all five of these genes into one apple tree, creating an apple clone particularly useful for the transfer of different combinations of the scab resistance genes into commercially acceptable varieties.
Weeden has co-invented a machine for DNA extraction, a machine that breeders can use on their own to prepare DNA samples. The machine takes 96 samples at a time and crushes them in less than five minutes using electromagnetic force. The resulting extracts, after dilution, are ready for PCR, where specific genes are multiplied so that their presence can be easily detected by chemical screening. Five laboratories around the world are currently testing the machine.
Norman Weeden graduated with a B.S. in Chemistry from Stanford University in 1969; with an M.A. in Biology from Humboldt State University in 1973; and a Ph.D. in Genetics from the University of California at Davis in 1981. He came to Cornell University as an Assistant Professor in 1982 and was promoted to Associate Professor in 1988.
Weeden is a member of the American Society for Horticultural Science, the American Genetics Association, the Botanical Society of America, and the Society for the Study of Evolution. He has served as associate editor for the Pisum Genetics Association since 1992, and associate editor of 'The Journal of Heredity' since 1987. His numerous publications discuss the development and applications of DNA and molecular markers, among other topics.
A 322 dpi b&w photograph is downloadable by clicking on the photo above.
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