INFLUENCE OF PLANTING DATE ON CANOLA AND CRAMBE PRODUCTION

Crop production in the upper Midwest, which has a short growing season , can be greatly affected by planting date. This study was conducted t o evaluate the effect of planting date on canola (Brassica napus L. an d B. campestris L.) and crambe (Crambe abyssinicia Hochst) seed yield, yield components, and plant growth characteristics. Three cultivars o f canola, two B. napus and one B. campestris, and one cultivar of cram be were evaluated at four planting dates during 1989 and 1990 in North Dakota. Canola seed yield was the highest at the first two plantings, early May and mid-May, and reduced at the two later plantings, late M ay and mid-June. Reduced yield at later plantings was attributed to fe wer pods per plant and a lower harvest index, The later maturing B. na pus cultivars produced greater yield than the B. campestris cultivar i n environments where growing conditions were near normal. Crambe seed yield also was greatest when planted in early and mid-May with reducti ons occurring at the later plantings of late May and mid-June, Crambe appears less susceptible to heat and moisture stress and higher yieldi ng than canola when grown in North Dakota.