Login

GPC Members Login
If you have any problems or have forgotten your login please contact [email protected]


DNA provides new insights on the control of invasive Russian knapweed

A recent study featured in the journal Invasive Plant Science and Management sheds new light on the control of Russian knapweed, an invasive plant found in the western U.S.

Russian knapweed grows in dense patches that can survive for decades. It can crowd out more valuable forage plants and is toxic to horses. As a result, it is classified as a noxious weed in 18 U.S. states.

Russian knapweed can spread two ways - by seed and by new shoots that emerge from root growth. To date it has been unclear which method is most common in local invasions, which makes it hard to develop an effective management plan.

To shed light on the best control methods, scientists from the USDA Agricultural Research Service and Montana State University analyzed DNA samples collected from six patches of Russian knapweed. The analysis showed each patch was largely or entirely composed of a single plant genotype, which indicates localized patches were spreading from Russian knapweed roots. Seed dispersal was shown to be the source of new patches, though, since each of the patches investigated was genetically distinct from other patches studied.

"Our findings provide important insights in how to best manage localized knapweed outbreaks," says John Gaskin, a botanist with the USDA Agricultural Research Service. "Controlling seed development may be effective at stopping long-distance dispersal of knapweed to create new patches, but is unlikely to control expansion of existing patches."

Land managers may want to reevaluate the controls they use based on the study findings. For example, with biological control, two of the three agents approved for use on Russian knapweed in the U.S. - a gall midge and a nematode - reduce seed production and above ground growth, thereby helping to reduce long-distance dispersal. The third biological control agent - a gall wasp - is able to stress existing Russian knapweed plants and thus may be more effective at controlling the growth of individual Russian knapweed patches.

Read the paper: Invasive Russian Knapweed (Acroptilon repens) Creates Large Patches Almost Entirely by Rhizomic Growth.

Article source: Cambridge University Press.

Image credit: Jeffrey L. Littlefield

News

Algae have land genes

500 million years ago, the first plants living in water took to land. The genetic adaptations associated with this transition can already be recognized in the genome of Chara braunii, a species of freshwater algae. An international research team headed by Marburg biologist Stefan Rensing reports on this in the journal Cell.


Rice plants evolve to adapt to flooding

Although water is essential for plant growth, excessive amounts can waterlog and kill a plant. In South and Southeast Asia, where periodic flooding occurs during the rainy season, the water depth can reach several meters for many months.


Invasive plants adapt to new environments, study finds

Invasive plants have the ability to adapt to new environments - and even behave like a native species, according to University of Stirling research.