A Study of Seed Germination and Seedling Growth Indices of Oilseed Rape (Brassica napus L.) Cultivars through Seed Vigour Tests

To evaluate the effects of accelerated aging and cold stress on seed germination and seedling growth indices in five oilseed rape cultivars (Hyola330, Hyola401, Hyola420, Syn3 and Pr401/15E), an experiment was carried out in a completely randomized design of three replications. Results indicated that the cultivars were significantly different in germination percentage, seed vigour, germination rate and seedling length under standard germination, cold stress and accelerated aging conditions. The cultivars Hyola401, Pr401/15E and Syn-3 in standard germination, Hyola401 in cold test and Pr401/15E and Syn-3 in accelerated aging test exhibited the highest germination percentages. Furthermore, Hyola420 had the lowest germination percentage in all the 3 tests. The cultivars were different for seedling length, seed vigour index and germination rate in different tests, so that Pr401/15E, in standard germination and accelerated aging test, and Syn-3, in cold test, had the highest seedling lengths. Moreover, Pr401/15E in standard germination test, Syn-3 and Hyola401 in cold test and Hyola401, and Pr401/15E in accelerated aging test, bore the highest seed vigour index. As for germination rate, Pr401/15E, Hyola401 and Syn-3 carried the highest values in standard germination, cold and accelerated aging tests, respectively. In total, evaluation of the germination indices under stress conditions indicated that the seeds of high vigour were less affected by cold stress and accelerated aging tests, the difference between their germination indices under normal and under stress conditions being low. Furthermore, accelerated aging decreased canola seed vigour more than did cold stress. This indicates that canola seeds lose their quality in high temperatures more rapidly than they do at low ones, so seed vigour would strongly decrease if seeds stored in unsuitable conditions of high temperature and moisture. Therefore, proper storage conditions of canola seeds are important before sowing of the seeds next year.