Studies on rapeseed production and cultivation science technology in China

摘要

China is one of the earliest countries that started to cultivate rapeseed in the world. Its ancient rapeseed cultivation could be traced to pre-historic times, with a history of 6000-7000 years. And the earliest record of rapeseed cultivation was about 2500 years ago. Since 1987, both China's rapeseed planting area and total yield have been the largest all over the world. It shows that direct relationships exist between the fast development of rapeseed production and innovation and application of cultivation science and technology. China is divided into two oilseed rape production regions, winter region and spring region. The former takes up above 90% of the total rapeseed planting area, which is further divided into 7 subregions, loess plateau subregion, Huanghuai plain subregion, Yunnan-Guizhou Plateau subregion, Sichuan basin subregion, middle reaches of Yangtze River subregion, lower reaches of Yangtze River subregion and coast of South China subregion. Three main species of oilseed rape,Brassica napus, B. rapa and B.juncea, were planted. Of them, B. rapa and B.juncea were mainly cultivated before the PRC was built. After middle 1950s, B.napus began to popularize. At present, it has reached about 95% of the total oilseed rape area, and B. rapa just makes about 4%, B.juncea makes about 1%. Based on the sensitivity to temperature and photoperiod, cultivating rapeseed in China could be divided into four types, which is, winter hardiness and weak response to photoperiod type(winter rape),distributed into centre and north of China, including loess plateau subregion and Huanghuai plain subregion, with a mean day-length of about ten and a halfhours before anthesis; half winter hardiness and weak response to photoperiod type(winter rape),mainly concentrated in the southwest of China and the reaches of the Yangtze River, including Yunnan-Guizhou Plateau subregion, Sichuan basin subregion, middle reaches of the Yangtze River subregion and lower reaches of the Yangtze River subregion, with a mean day-length of about eleven hours before anthesis; Spring hardiness and weak response to photoperiod type(winter rape), distributed into the coast of south China and parts of southwest of China, with a mean day-length of about eleven hours; spring hardiness and high response to photoperiod type(spring rape), with a mean day-length of above fourteen hours. To adapt to different farm regions with different farming resources and complex ecological conditions, varieties of cultivation modes and technologies has been built. Their significant characters are high yielding and multi-crop systems, for example, in the reaches of the Yangtze River, rape-rice double crops system mainly, concurrent with rape-cotton double crops system and in triple crops system regions, existing rape-rice-drought (e.g. soybean, sweet potato, corn) system and rape-drought crop-drought crop system, such as corn-potato-rape, corn-corn-rape etc. Spring rape usually adopts one crop system. Since late 1980s, it has been developing double-low rapeseed and advancing cultivation technology of improving seed quality and yield,raising work efficiency and saving labor hours in the rapeseed production. As to the prospect of China's rapeseed industry, on the one hand people's living standard has greatly improved, their dietary pattern is changing fundamentally, which will enlarge the requirement of edible rapeseed oil inevitably; on the other, as an optional source of bio-diesel, rapeseed has been predicted to enter into a new stage of high-speed development. In the reaches of the Yangtze River, there are about 20 million hectare winter fallow field for rapeseed production each year. Therefore, combined with the prospect that oil content raise from 42% to 50%, yield level increase from 1800kg/ha to 3000kg/ha through variety improving and cultivation technology innovation, there is strong potential for the development of rapeseed production.