Effects of planting date on seed oil yield quantity and quality of four canola (Brassica napus L.) cultivars

摘要

Canola is one of the most important oil plants and plays a great role in provision of food oil. It is in the third rank in this respect following soybean and palm oil. Different factors affect directly or indirectly on oil yield of canola. One of the important factors is planting date. Therefore four different planting dates (September 6, 16 and 26 and October 6) were evaluated on quality traits of four winter canola cultivars (Colvert, Orient, SLM046 and Regent*Cobra) in Research Field of Agricultural Research Seed and Plant Improvement Institute. Experimental design was strip plot laid out in complete block design with four replications.Planting dates and cultivars showed a significant difference for grain yield. The second and third planting dates showed the highest and lowest seed yield with 4768 and 3264 kg/ha, respectively. Orient and SLM046 cultivars had the highest and lowest grain yield with 4225 and 3679 kg/ha respectively. The maximum and minimum grain protein percent were for Regent*Cobra and Colvert respectively. Protein and oil yield were more in plants with early planting dates than late planting dates. Late planting can negative effect on grain glucosinolate rate and it may be increased. Canola grain obtained from early planting dates (6 and 16 of September)had lower glucosinolate (6-6.08 μmol/mg) than treatments with late planting dates. Four canola cultivars had different glucosinolate. Colvert (6.05 μmol/g) and Orient (6.12 μmol/g) cultivars had less glucosinolate than Regent*Cobra (6.6 μmol/g)and SLM046 (6.71 μmol/g) cultivars. Average oil percentage was 41.28% with the highest percentage for Regent*Cobra (%41.71)and the lowest for SLM064 (%40.78). Four canola cultivars had erosic acid less than 1%. Thus it can be used in human nutrition.In this research the best planting date was 6 and 16 of September. Higher level of monounsaturated and polyunsaturated fatty acids such as oleic, linoleic and alpha-linolenic were found mainly in canola oils, so animal fat and even other vegetable oils can be replaced by canola oil in the diet. Seed oil of four canola cultivars had the lowest level of eicosenoic fatty acid, so canola oil had high quality. The Orient cultivar was superior to other cultivars due to the highest protein percent and more oil yield.