Breeding And Demonstration Of The New Double-low Rapeseed (Brassica Napus L.) Varieties

The double-low rapeseed (canola) market situation of the Yangtze River valley and main problems that influenced the rapeseed production of China were presented in this paper. To be convenient for popularization and application of canola, several double-low rapeseed cultivars with high yield, strong resistance to disease, good comprehensive agronomic characters and high oil content were developed, and high-yielding cultivation techniques were utilized. Demonstration and promotion of canola were held, for that the farmers accepted the new cultivars, and grasp the high-yielding cultivation techniques. Main results of the present study were as follows:1. The efficiency of integrating three agronomic traits (high yield, resistance to disease and double-low quality) was significantly enhanced by the improved selection procedure, which was from resistance to disease, to high yield, ultimately to double-low quality.2. The genic male sterility (RGMS) controlled by three pairs of recessive genes had great potential for hybrid seed production in virtue of the characteristics of complete and stable male sterility, ease of transference of the male sterility genes to diverse genetic backgrounds and comprehensive restorer lines. Moreover, a 100% sterile population can be obtained via temporary maintainer, which made three-line systems available in hybrid seed production.3. The demonstration consisted of promotion of the new cultivars, technology training, as well as the farmers grasping the key techniques of high-yielding cultivation. It have good effect for the rapeseed production by demonstration households of science and technology, experimental demonstration for steady and high yield, and step-by-step promotion based on the traditional canola growing areas.4. The high-yielding cultivation techniques such as applying the top dressing in bud appearing stage, double thin planting and double early development techniques, were put forward.5. China seed industry could grow bigger and stronger, only taking full advantage of the combination between scientific research institutions and seed industries.6. The value of canola only embodied in good quality, which could be obtained by solely purchasing and processing the double-low rapeseed different from ordinary rapeseed. However, the household contract responsibility system caused trouble to ensure good quality.