The Effect of Drought on Population Dynamic of Volunteer Rape Seed (Brassica napus L.) in Darkness

In order to evaluate effects of drought and darkness on secondary dormancy of Brasica napus, a factorial experiment based on completely randomized design with 3 replications. The treatments included 7 various canola (Hyola 60, Hyola 308, Hyola 330, Hyola401, Hyola 420, Sarigol, AA1) and 3 drought levels (control, -1.5 MP water potential and dry seed). Samples were placed inside black cover in growth chamber with 20°c for 2 weeks. Results indicated that the highest and lowest germination percent was observed in Hyola420 and Hyola60, respectively. The percentage of germination of varieties decreased under the different drought levels significantly. The percentage of cumulative germination in total canola varieties under -1.5 MP was more than dry seeds, considerably. In general, in addition to genotype, environmental conditions affect on secondary dormancy potential of seeds. In total varieties, except of Hyola60, germination percent and rate was decreased, due to enviromment moisture.