Effect of sowing date at seed filling period on canola (Brassica napus) seed vigor

In order to study the effect of sowing date during seed filling period on canola seed vigor, an experiment was conducted at Agriculture Research Station of Gonbad during 2005-2006. Two cultivars of canola (Hyola401 and RGS003) were sown in five sowing dates, and compared based on split plot design in 3 replications. Standard germination, seedling growth rate and electrical conductivity tests were used to evaluate seed vigor. The results showed that seed fill duration, 1000-seed weight, seed quality, and seed yield of canola were decreased with a delay in sowing date from 15 Aban. Seed vigor treats were affected by environmental conditions, such as air temperature, during seed filling period. The seed test result revealed that, in both cultivars, delaying in sowing date from 15 Aban, caused decrease in germination percentage, germination rate, uniform germination, number of normal seedling, seedling dry weight, and increase in electrical conductivity. Therefore, just canola seeds from optimum sowing date can be used to sown in the next year.