Seed coats of someBrassica andSinapis weedy and cultivated in Canada

Abstract

A number of species of Brassica and Sinapis are important cultivated plants or weeds in Canada. Turnip Rapeseed, B. campestris L., and Swede Rapeseed, B. napus L., were grown on 3,200 acres in Canada during 1943 1944, but by 1969 1970 the acreage had increased to 2,012,000 (Downey et al. 1970). In 1969 1970, 37,020,800 bushels of rapeseed were produced on the Canadian prairies. In 1969 1970, 200,000 acres of White Mustard, S. alba L. and Indian Mustard, B. juncea (L.) Czern. were also grown in the three prairie provinces. Other species of Brassica commonly cultivated in Canada are: Turnip (B. campestris), Black Mustard (B. nigra (L.) Koch), and Kale, Cabbage, Kohlrabi, Brussels Sprouts, Cauliflower and Broccoli (all varieties of B. oleracea L.). In addition, Wild Mustard, S. arvensis L., and Bird Rape, B. campestris, are serious weeds in Canada and Indian Mustard, B. juncea, Black Mustard, B. nigra, and Swede Rape, B. napus, are occasionally weedy (Frankton & Mulligan 1970; Mulligan & Bailey 1975). Wild Mustard and Bird Rape are frequently weeds in cultivated fields of Brassica, Sinapis and other annual crops. In addition, cultivated Brassica and Sinapis volunteer as weeds in other annual crops, including fields sown to other cultivated Brassica and Sinapis. Since seed of these annual crops may contain seed of one or more weedy Brassica or Sinapis, it is important to be able to identify seed of the different Brassica and Sinapis. Although morphological differences are outlined in Musil (1948), McGugan (1948)