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

Shallow soils promote savannas in South America

New research suggests that the boundary between South American tropical rainforests and savannas is influenced by the depth to which plants can root. Shallow rooting depth promotes the establishment of savannas. Previous research has shown that precipitation and fire mediate tropical forest and savanna distributions. The study shows that below ground conditions need to be considered to understand the distribution of terrestrial vegetation both historically and in the face of future climate change. The study by researchers of the Senckenberg Biodiversity and Climate Research Centre and Goethe University is based on computer vegetation models and was published in the Journal of Biogeography.


Living mulch builds profits and soil

Living mulch functions like mulch on any farm or garden except -- it's alive. No, it's not out of the latest horror movie; living mulch is a system farmers can use to benefit both profits and the soil. While the system has been around for a while, scientists at the University of Georgia are making it more efficient and sustainable.


Sequencing of stevia plant genome revealed for first time by Purecircle Stevia Institute

For the first time, scientists have completed the sequencing of the stevia plant genome. Lead scientists from PureCircle Stevia Institute and KeyGene have unveiled this major breakthrough in research showing the annotated, high-quality genome sequences of three stevia cultivars.