Campus News

Published by Communications and Public Affairs (519) 824-4120, Ext. 56982 or 53338

News Release

March 16, 2000

Agriculture News Tips: Earthworms work as nature's plow; new test for potato disease; low-tech berries

When farmers turn their attention to plowing this spring, they might be better off leaving at least part of the job to earthworms, a University of Guelph soil scientist says.

"There is a definite lack of appreciation for the precise contribution earthworms have on soil structure," said Prof. Bert VandenBygaart, Department of Land Resource Science. VandenBygaart is working with Cathy Fox from Agriculture and Agri-Food Canada to accurately determine what proportion of soil structure is largely influenced by the natural tunneling activity of earthworms.

In traditional agriculture, farm fields are mechanically plowed every year to aerate soil, reduce weeds and promote drainage and nutrient cycling. The problem is that plowing can lead to erosion and loss of valuable soil, and kill earthworms, VandenBygaart said.

"We need to understand earthworms' impact on soil, so their benefits can be built upon and current agricultural practices improved," he said.

By digging small tunnels through the soil, earthworms build porous networks that promote efficient water and nutrient cycling. Worms mix the soil by feeding on organic residues at the soil surface and dragging them back down into their burrows, leaving nutrient-rich fecal castings in their trail that can be readily taken up and utilized by plants.

The researchers are using hand-sized blocks of soil, digital images and computer modeling in their work.

Contact: Prof. Bert VandenBygaart Department of Land Resource Science (519) 824-4120, Ext. 4275

A devastating disease that causes half of all potato losses in Ontario could soon be controlled, thanks to a quick diagnostic test being developed at the University of Guelph.

Profs. Jane Robb and Ross Nazar, Department of Molecular Biology and Genetics, are working with Prof. Ali Khan, Department of Plant Agriculture, to develop a method to detect the verticillium fungus, which stunts the growth of infected plants and leads to early plant death.

"Early dying syndrome causes major crop losses to potato growers in Ontario and around the world," Robb said. "It's crucial for us to find ways of detecting the fungus early on before the disease sets in."

Because verticillium resistance in potatoes depends on a number of genes rather than a single gene, it is difficult to breed a resistant line. Robb and her colleagues are pursuing a detection method based on molecular genetics that screens soil samples for the presence of verticillium genetic material.

"The economic impact of this technology will be felt not only in Ontario where early dying syndrome is a major potato disease, but also on national and global levels," Robb said.

Contact: Prof. Jane Robb Department of Molecular Biology and Genetics (519) 824-4120, Ext. 2529/8311

Genetic engineering may be heralded as a new phenomenon, but traditional plant breeding methods using unsung "low-tech" approaches to mix genes have been successfully producing new and more desirable varieties of many crop plants for years, including strawberries bred by University of Guelph researchers.

Prof. Alan Sullivan, Department of Plant Agriculture, and PhD student Bob Bors have modified traditional breeding methods to cross North American commercial strawberry cultivars with exotic, wild ones. Their research produced a new strawberry species with an unprecedented genetic mix, offering unique flavors, stronger disease and pest resistance and longer growing seasons.

Through traditional breeding, the researchers have found a way to transfer blocks of genes with desirable traits between different species of strawberries. Transferred genes come from strawberries only, in contrast to "high-tech" biotechnology, in which genes can be moved among plants, animals and bacteria.

Using a process called synthetic octoploid production, Sullivan and Bors increase the number of chromosomes of wild strawberry species so they can be successfully crossed with local cultivars. These genetically compatible wild species enable breeders to generate a greater number of different types of strawberries.

Broadening the genetic strawberry population also helps make them less susceptible to disease or pests and more suited to specific growing conditions, Sullivan said.

Contact: Prof. Alan Sullivan Department of Plant Agriculture (519) 824-4120, Ext. 2792

For media questions, contact Communications and Public Affairs, (519) 824-4120, Ext. 3338

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