Effects of harvesting time and drying temperature and duration on seed viability, vigour and some other related traits of two oilseed rape (brassica napus l.) Cultivars

To study the effects of harvesting time and drying temperature and duration on seed viability, vigour and some other characteristics of two oilseed rape cultivar PF7045/91 (Sarigol) and SLM064, an experiment was conducted for two years (2000 and 2001) in Seed and Plant Improvement Institute. Seeds of both cultivars with 45%, 30% and 15% moisture contents were harvested 222, 229 and 236 days after planting and dried in air force oven at 45,55 and 65 centigrade degrees for 12, 18 and 24 hours. Some important characteristics such as primary and final germination percentages, normal and abnormal seedlings number, mean daily germination rate, seedling and primary roots length, fresh and dry seedlings weight and seedling vigour index were measured. Combined analysis of the data showed that the primary and final germination percentages, mean daily germination rate and seedling weight were affected by cultivar x seed moisture contents x year interaction. The highest pecentages of primary and final germination belonged to seeds of cultivar PF7045/91 harvested 222 days after planting with 45% moisture content, and cultivar SLM046 harvested 236 days after planting with 15%moisture content, respectively. Seeds of SLM046 cv. with 15% moisture content produced the highest number of normal seedlings and had higher mean daily germination rate. Seeds of PF7045/91 produced seedlings with higher length and dried and fresh weights compared to SLM046. Seeds of PF7045/91 harvested 236 days after planting with 15%moisture content and dried at 45oC for 12 hours had higher viability. Increase in drying temperature and duration, increased seed viability in PF7045/91. In the light of the results, seeds of SLM046 cv. harvested with 15%moisture content 236 days after planting, dried at 55oC for 24h and seeds of PF7045/91 cv. harvested with 30% moisture content 229 days after planting, dried at 45oC for 18h had the highest quality.