THE BIOLOGY OF CANADIAN WEEDS - 108 - ERUCASTRUM-GALLICUM (WILLD.) SCHULZ,O.E

A review of biological information is provided for Erucastrum gallicum (Willd.) O.E. Schulz. A European native, it was introduced into Canad a and the United States in the early 1900s and spread rapidly along th e railroads. The species occurs in all the provinces and the Northwest Territories and is particularly abundant in the Prairie provinces and midwestern United States. It is a summer annual, rarely a winter annu al or biennial species, and is characterized by high reproductive outp ut. Plants occur most commonly on waste ground and along roadsides and railroads, followed by agricultural fields. Erucastrum gallicum is of allopolyploid origins (n = 15, 7 + 8 chromosomes), and contains a sin gle multi-locus isozyme genotype. The species is a close relative of B rassica and is capable of limited genetic exchange with the canola spe cies, B. rapa and B. napus. The possible transfer of genes from transg enic canola varieties to Erucastrum gallicum poses a remote, but poten tial, environmental risk. Populations of Erucastrum gallicum, includin g both Old World and North American populations, constitute a valuable germplasm resource as potential sources of beneficial agronomic trait s, such as disease resistance for canola crop improvement.