
The Weed-Competitive Ability of Canada Western Red Spring Wheat
Cultivars Grown under Organic Management
H. E. Mason1, A. Navabi1, B. L. Frick2, J. T.
O’Donovan3 and D. M. Spaner1
Abstract
Competition from weeds can reduce grain yields in both conventional
and organic systems. Plant height, tillering, and elevated photosynthetically
active radiation interception are some of the traits thought to help
confer competitive ability in cereal grains. Crop cultivars developed
before the advent of modern, high-input agriculture may be better suited
to lower soil nutrient levels and elevated weed competition.
Twentyseven spring bread wheat (Triticum aestivum L.) cultivars,
representing 114 yrs of Canadian wheat breeding, were grown at conventionally
and organically managed sites in north central Alberta over a 3-yr period.
Average conventional yields were 63% greater than organic yields, and
average overall weed biomass was significantly greater under organic
management. Earlier flowering and maturity were more important for achieving
high grain yield in organic fields than in conventional fields. Greater
numbers of spikes m-2 were associated with increased grain yield in
organic fields but were not in conventional fields.
In organic fields, increased plant height and early maturity were associated
with reduced weed biomass, while strong early season vigor was related
to increased yield, increased spikes m-2, and reduced weed biomass.
A competitive crop ideotype for organically grown spring wheat in northern
growing regions of the Canadian Prairies should include taller plants,
with fast early season growth, early maturity, and elevated fertile
tiller number.
Source
Crop Science (2007) 47:1167–1176
Author Locations and Affiliations
(1)
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5
(2)
Department of Plant Sciences, University of Saskatchewan, 51 Campus Dr., Saskatoon, SK, Canada S7N 5A8
(3)
Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, Lacombe, AB, Canada T4L 1W1
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Posted October 2007