ICOM1 Abstract
session 4 or 8
CLAPPERTON, JILL, DERRICK KANASHIRO, & BOB BLACKSHAW. Agriculture and
Agri-Food Canada, Research Centre, P.O. Box 3000, Main, Lethbridge,
Alberta, T1J 4B1 Canada. - A preliminary study on the influence of VAM
fungi on the ecology of grassy weeds in agroecosystems
The objective of this study was to compare the inoculum density and
colonisation by VAM fungi of the grassy weeds downy brome (Bromus
tectorum), green foxtail (Setaria viridis), foxtail barley (Hordeum
jubatum), and wild oats (Avena fatua) with that of hard red spring wheat
(Triticum aestivum). Percent of root length colonised by VAM fungi was
compared in both grassy weed species and wheat which had been collected
at the end of the growing season. Soil was also collected at the field
sites from both the weed plots and adjacent wheat plots and used in
greenhouse studies to compare the infectivity of the soils using the
weed species, wheat, and green onions. Our preliminary results from the
field collections showed that the weeds were more heavily colonised by
VAM fungi than wheat, and that foxtail barley was the most colonised,
and green foxtail the least. When all the weed species, wheat, and
green onions were grown in each soil, the wheat and green foxtail were
not infected, the remaining weed species were infected and showed some
colonisation in spots along the root, with no preference for a
particular soil. The onions were infected in all the soils, with soil
from under wheat having the least infectivity (< 10%) and soil from
under downy brome, foxtail barley, and green foxtail having the most
(70%).