1985 Volume 54 Issue 3 Pages 364-370
Germination tests of seeds were carried out at 5 different temperatures, i.e., 5, 15, 25, 35, and 45°C, using 11 different crops of Brassica. Germination was examined every two hours and, afterwards, every 12 or 24 hours. In every crop, seeds began to germinate earliest at 35°C and latest at 5°C. The start of germination became later in the decreasing order of temperature from 35 to 5°C. Seeds at 45°C began to germinate as early as those at 35°C in many crops, but in some crops the start of germination was much delayed. Mean germination period was shortest at 35°C, and shorter at 25°C in every crop. These temperatures were followed by either 15 or 45°C with respect to mean length of period. The longest period was needed for germination at 5°C. As for germination percentage, seeds at 35, 25 and 15°C showed more than 85% in all of the crops examined. At 45 or 5°C, low percentages of germination were frequently observed. Differences among crops were observed at these temperatures: some crops showed bad germination at 45°C, and some at 5°C, and others at both 45 and 5°C. The response of non-dormant seeds was different from that of dormant seeds in terms of germination temperature. Optimum temperatures for germination of non-dormant seeds were higher than those of partially dormant seeds.