Parsnips are native to Eurasia and have been cultivated as a food crop globally for more than five centuries. Wild parsnip, though, is considered a globally invasive weed – crowding out native species and producing a sap that can trigger painful rashes. A new study featured in the journal Invasive Plant Science and Management indicates that invasive wild parsnip (Pastinaca sativa) is genetically a lot closer to its vegetable cousin than previously thought.
To inform more effective management strategies, a team from the University of Illinois set out to determine whether invasive wild parsnip originated from escaped parsnip crops or from the accidental introduction of a wild subspecies from Eurasia as a consequence of international travel and trade.
Researchers collected and analyzed genetic markers from wild parsnip growing in its native range in Europe. They did the same with wild parsnip in regions of North America and New Zealand where it is considered invasive. They also examined domesticated parsnip cultivars from the same regions.
The data showed that cultivated parsnip and wild parsnip are not genetically distinct. Instead, both share the same genetic variants. This stands in stark contrast to carrots, for example, where wild and cultivated varieties exhibit significant genetic differences.
“With no genetic differentiation, it is difficult to determine with certainty whether wild parsnips escaped cultivation or whether they were recently bred from wild strains,” says Tania Jogesh, Ph.D., lead author of the study and now a postdoctoral researcher at the Chicago Botanical Garden.
One possible clue, though, is the high level of genetic diversity researchers found within the wild parsnip plants in each of the regions studied. Scientists say this diversity might be attributable to multiple introductions of seeds that were accidentally transported over long distances by humans.
Full text of the article “Patterns of Genetic Diversity in the Globally Invasive Species Wild Parsnip (Pastinaca sativa)” is available in Volume 8, Issue 4 of the journal Invasive Plant Science and Management.