Meristem: Crop Science

Farmers' voice critical in Alberta's Land-use Framework consultations more
SCCC concerned with "Carbon Pricing Policy for Canada" report more

Archives

Research unveils crop-boosting benefits of natural soil fungi

Date posted: September 30, 2002

Scientists are shedding new light on natural soil fungi that may hold a key to greater fertilizer efficiency in wheat production

Researchers at the University of Saskatchewan are studying the dynamic benefits of arbuscular mycorrhizal fungi (AMF), which act as root extensions to improve nutrient and water uptake in wheat and other host crops.

Crop cultivars bred to take advantage of these fungi may lead to everything from superior plant growth and yield, to stronger disease resistance and drought tolerance – all with less reliance on fertilizers and other inputs, says Dr. James Germida, Head of the University’s Department of Soil Science. This research is supported in part by the Endowment Fund, administered by Western Grains Research Foundation.

“The potential long-term impact of this research is enormous,” says Germida, a soil microbiologist and biochemist. “If we can ultimately identify and understand the wheat plant genes that control and regulate symbiosis with this fungi, we can ensure that new wheat cultivars are developed to take advantage of its many benefits.”

AMF have a mutually beneficial relationship with wheat, legumes and other host crops, and are believed to have evolved within native soils for millions of years, says Germida. In exchange for feeding on trace amounts of plant material, they act as root extensions that allow the plant to gather more nutrients and water from the soil. “It’s a beneficial symbiosis that is quite fascinating, but it’s something we haven’t known a lot about.”

Studies by Germida and colleagues over the past decade show that a variety of AMF species occur naturally in Canadian prairie soils, where they colonize the roots of wheat and legumes to various degrees.

A key concern for researchers has been the ability of modern wheat cultivars to take advantage of the fungi, says Germida. But the team’s most recently completed study has helped put this to rest.

“Because wheat breeding programs select cultivars under conditions where fertilizer use is common, our hypothesis was that they run the risk of selecting material with fewer genes that favor AMF – but this wasn’t the case,” he says.

The study compared the ability of modern and historic wheat cultivars to benefit from AMF. A total of 17 wheat varieties were examined, but researchers focused primarily on three. These included two historic cultivars, the Turkish variety PI 167549 and Canada’s Red Fife, chosen as representative of cultivars not subjected to modern plant breeding, and CDC Teal, chosen as representative of today’s popular spring wheat cultivars.

While the study found no major differences between these types under most conditions, it did identify differences in the growth patterns of historic cultivars that may produce an advantage in soils with low phosphorous.

“The good news is that it appears breeding practices have not interfered with AMF association,” says Germida. “However, the findings also indicate that older wheat cultivars might respond better to the fungi when phosphorous is limited – this may prove significant for organic and low-input farmers.”

Further research is needed before specific cultivars and production strategies can be developed to make the most of AMF’s crop-boosting benefits, he says. But indications are that rotations and fertilizer applications will play a fundamental role.

“Our findings have suggested that excess soil phosphorous can inhibit the development of AMF. We’ve also found that wheat’s benefits as a host crop for AMF can improve the performance of crops seeded into wheat stubble. Based on these results, proper management of crop rotations and fertilizer regimes currently seem to be the most important tools for exploitation of AMF symbiosis in the field.”

Western Grains Research Foundation’s Endowment Fund has contributed over $17 million to nearly 200 crop research projects in Western Canada since its inception in 1983.