Abstract At present, the researches on crop genetic engineering are mainly for the sake of the improvement of plant resistance, while yield is a complex agronomic trait, controlled by various genes and environment. Photosynthesis, nitrogen assimilation, distribution of carbon source and plant architecture are widely considered as the base of yield formation. With the advance of Plant Genome Project, a lot of genes regulating the above physiological process have been identified and genetically modified, which resulted in the improvement of crop yield. Isolation of the genes as well as validation of gene function will provide the novel mind and a set of new methods for breeding high-yielding varieties, although the molecular mechanism that the genes regulate the traits is still unknown. With the implementation of the Important National Project of Transgenic New Variety Cultivation, identification of functional genes will be paid more and more attention. The researches on the important genes related to plant yield are summarized in the article on the basis of source, translocation, sink, plant architecture and nitrogen utilization contributing to yield formation in crops, which are expected to contribute to cultivating transgenic crops of high yield.
