Submitted to: American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/2005
Publication Date: 5/1/2005
Citation: Palumbo, R., Hong, W., Hu, J., Krause, C.R., Locke, J.C., Craig, R., Tay, D., Wang, G. 2005. Trap markers help categorize a pelargonium collection. American Society for Horticultural Science [abstract]. HortScience 40(4):1067.
Interpretive Summary: The USDA, ARS, Ornamental Plant Germplasm Center (OPGC) at Ohio State University in conjunction with USDA, ARS, Greenhouse production Research Group and the University of Toledo, maintains a collection of herbaceous ornamental plants in order to protect future breeders from a loss of genetic diversity. The current OPGC geranium collection includes approximately 870 sources of geraniums. A molecular technique showed that Target Region Amplified Polymorphism (TRAP) has promise for analyzing the variation in the species to actually “fingerprint” geraniums. The use of labeled primers, chemicals that permit identification, allows analysis of the samples to be aided by a computer. TRAP involves the use of both a fixed and a random agent in a technique called Polymerase Chain Reaction, that only require extremely small quantities of plant materials. This will lead to a search for genes that control disease and insect resistance. Analysis of such data by computer programs shows that a geranium population can be segregated into groups of similar accessions. Next a small population of the above collection will be used for further study on the precision and accuracy of TRAP as compared to other molecular markers using a mite resistance gene from geranium that has already been sequenced or identified, resulting in improved management practices for growers.
Technical Abstract: The Ornamental Plant Germplasm Center (OPGC) maintains a collection of herbaceous ornamental plants in order to protect future breeders from a loss of genetic diversity. The current Pelargonium collection includes approximately 870 accessions. Our preliminary studies showed that TRAP (Target Region Amplified Polymorphism) has promise for analyzing the variation in our collection, and so we have expanded the study to analyze the entire Pelargonium collection. We have used the same primers for this screening of Pelargoniums as were used on sunflowers, and TRAP results run on a sequencing gel showed 90-150 bands that segregate the population into groups of similar accessions. In order to facilitate analysis of OPGC’s large population, we have converted the method to a high throughput technique that efficiently analyzed the entire population. We used a 96 well DNA extraction kit from Qiagen that produced high quality DNA in spite of the high level of phenolic compounds in some Pelargonium species. Also, the use of labeled primers allowed analysis of the gels to be aided by a computer. These results produce a categorization of the collection that, combined with morphology and taxonomy, will form the basis for future studies that will use target genes of ornamental importance specific to Pelargonium.