Advance and existing problems of super high-yield breeding of rice

The per unit area yield of rice in China has been increased significantly since the rice breeding for dwarfness was extended and hybrid rice was bred and applied from 1960-1970's.In order to increase the output efficiency of per unit area land,super-high yield breeding of rice was put forward by Japanese in the 1980's firstly.The super high-yield breeding of rice in China began in the mid 1990's,and it has achieved some goals.At present,superhigh yield breeding of rice is a hot topic in cropping science of rice research.The article summarized the super high-yield breeding theory and methods of rice,and it mainly included that 1) the theory of new plant type breeding;2) the combination of ideal plant type and the utilization of heterosis is a developing trend in super high yield breeding of rice;3) the crossbreeding of indica-japonica subspecies is the main method;4) to breed super-high-yield combinations by using elite genes of wide rice.Some existing problems in super high yield breeding were pointed out as: the integration of super high yield and good grain quality;traditional breeding methods and modern biotechnology can not be integrated well,and the integration of super high yield and resistance.