Abstract
Rapeseed oil is major edible oil in Japan and mostly imported from Canada and Australia. Though rapeseed (Brassica napus L.) is cultivated in small area (several hundred ha) in Japan, our laboratory of NARCT has bred five rapeseed cultivars with no erucic acid in oil, and one of them, Kirari-boshi, shows double low quality (no erucic acid and low glucosinolate). They are winter type, show strong to medium tolerance to winter injure, and their yield is about 300 kg/10a in trials. Cultivar with double low quality is globally standard for edible rapeseed oil and DNA markers for some fatty acid composition have been developed. Mutation breeding enabled to heighten oleic acid and/or reduce linolenic acid. Then, cultivars with simultaneously high oleic acid and low linolenic acid are also produced, which shows good quality (resistant to oxidation). Since biosynthetic pathway of oil formation has been elucidated and related genes cloned in recent years, transgenic technology has produced novel rapeseeds with high lauric, high myristic or high stearic acid. High yield is primarily breeding target of our laboratory, and high oleic acid or double low is also important since specialty oil would enhance rapeseed cultivation.
