Prospects of rapeseed production in warm and cold dry-land areas of Iran

摘要

About 80% of the need of edible oil of the country is met through imports. There are now efforts to create and develop area for important oilseed crops with emphasis on rapeseed Almost 60% of the cultivated area in the country is rain-fed, therefore there is planning to bring more area in the dry-land region under suitable new oilseed crops. Elaborate research in the last five years was conducted at dry land research stations of the country. The stations where oilseed crop research was conducted are located at Sararood, Maragheh, Gachsaran, Sanandaj, Ilam and Shirvan. Results showed that end of November was the best sowing date for rapeseed in warm as well as semi-cold dry-land areas. Spring type rapeseed hybrids from Australia and Canada perform better in warm climates, which prevails in the North and South of Iran. Results revealed that in some areas like Sararood mustard varieties from Canada produce economical yield, more than rapeseed and surprisingly as cold tolerant as rapeseed winter type. Generally in production of yield rapeseed winter type are the best followed by mustard, spring type rapeseed and rapa varieties in rainfed conditions. Results showed that at lands receiving up to 400 mm rain during the season, highest yield of 2.1 t/ha was obtained with 50 kg N and 15 kg P/ha. There was no difference between the yield of zero doze (1371.1 kg/ha) to 20 kg/ha (1371.5). Sulphur application should be based on the effective response in the area. Based on results it is recommended that in semi-cold areas 10 kg/ha seed may be used to cover the risks of cold temperatures and late rains. In warmer areas 6 kg/ha may be adequate. Results have demonstrated that early season weed control in rapeseed is critical in minimizing yield loss due to weeds. Competition studies have shown that if rapeseed are maintained free of weeds till the stem elongation stage after sowing, the weed seedlings which emerge later do not cause significant yield reduction.