[1] Agriculture and Agri-Food Canada, Soils and Crops R. and D. Centre, 2560 Hochelaga Blvd., Ste-Foy, Que. G1V 2J3, Canada
[2] Dep. of Biological Sciences, Univ. of Lethbridge, 4401 University Dr., Lethbridge, Alta. T1K 3M4, Canada
[3] Agriculture and Agri-Food Canada, E. Cereal and Oilseed Res. Centre, Central Experimental Farm, Ottawa, Ont. K1A 0C6, Canada