From Roots to Fruit:
Seeking the Essence of Plants

Jean Gerrath in the Biology Research Complex Greenhouse at UNI

From a decades-long interest in how members of the grape family (Vitaceae) develop, Jean Gerrath's specialty has grown to include the identification of different grape varieties grown in Iowa. It all began with a Pella couple who contacted the professor of biology to find out exactly which grape variety they were growing. Because the growth and development of grape varieties-how shoots grow at their tips, bud and leaf shape, when and where flowers develop--have not been systematically characterized, identification has become a serious problem. Varieties are easily misidentified because when the plants are sold, they look like little sticks.

And why is this a concern in Iowa? For the simple reason that the Iowa grape industry is expanding rapidly. After its revival in 2000, the industry produced 90 tons of grapes in 2002 and is predicted to yield 250 tons in 2005. Gerrath, the first president of the Iowa Grape Growers Association, says that one to five percent of all Iowa vines are mislabeled. So, clearly, a lot is at stake for this vibrant new industry. Misidentified varieties reduce quality and profit considerably.

To help establish Iowa's emerging wine industry on a firm footing, Gerrath has started a Grape Identification and Certification Center, with the idea of developing both morphological and molecular identifiers for varieties of grapes. Now in the first phase, morphological identification, the Center has published A Midwesterner's Handbook of Grapevine Varieties. The handbook is based on the work of Emily Lehman, Gerrath's research associate and an instructor in the Biology Department, who collected samples of 20 commonly grown varieties of grape from UNI's experimental vineyard and from ISU's experimental plot at Nashua. The handbook contains photos of the kinds of characteristics a farmer could easily observe. This first issue covers 11 varieties, and plans are under way to expand the handbook with another 10 or 15 varieties. The intent is that growers would be able to make most identifications themselves by using the handbook, with the Center assisting with more complicated identifications.

The second phase of the Center, molecular identification, will involve developing a protocol that will allow DNA fingerprinting on the varieties of grapes grown in the Midwest. By running a DNA profile on a ground-up leaf from a vine's first growing season, Gerrath and her colleagues will be able to identify an unknown plant by comparing its profile to a database of DNA profiles of known plants. Eventually the Center will expand its services to test for the presence of pathogens so that a farmer or nursery will be able to certify that a particular stock is disease-free. Though in its early stages, the Center has made an ambitious beginning. Gerrath and other faculty members are pursuing external funding that will allow them to fulfill the Center's potential.

Meanwhile, Gerrath's interest in Vitaceae continues unabated. She is co-organizing a symposium on the biology of the Vitaceae at which scientists from all over the world will present their research as part of an international botanical congress in Vienna in July of 2005. She hopes to have all of the research papers published in a monograph. Earlier in the summer, Gerrath and a student from the University of Guelph in Ontario will collect wild grape materials in the Mississippi River valley. They will use the same techniques and skills for identification of varieties as those used for the handbook. Gerrath points out that wild species of grapes and cultivated varieties can interbreed. Out of those hybrids and out of selections by growers from varieties in Europe and North America come at least 8000 varieties that are cultivated.

Another area of interest for Gerrath is roots. Years ago, when examining some of the plants that grow on cliffs in Iowa, she noticed that all of the plants belonging to this family have an internal structure, called a phi thickening, inside of the root. Some botanists have hypothesized that these structures may enable the roots to penetrate the cliffs, but no investigations have tested the truth of this hypothesis. During her most recent professional development leave, Gerrath grew some of the plants under various conditions at the University of Guelph, where she is an adjunct professor. She wanted to find out if plants that normally do not produce this structure would do so under certain conditions. She found that phi thickenings are genetically determined. In other words, whether or not they occur cannot be changed, but environmental conditions can influence the size of the structures. Deana Lickteig, a biology graduate student, is assisting Gerrath with this research.

Following is a selected list of Gerrath's publications related to the work discussed above as well as her e-mail address.

jean.gerrath@uni.edu