A noninvasive method of source-sink regulation in rice belongs to the technical field of rice production. In this method, the source-sink relationship is regulated by a rice sterile line and its identical type of maintaining line being subjected to mixed-planting and insulated pollination, or sowing and transplanting at different times and insulated pollination, so as to construct rice plant samples with gradient difference of source-sink levels. The present invention is a kind of native, natural noninvasive method of source-sink regulation, which could broaden the traditional thinking of source-sink theoretical research, especially overcome the deficiency in conventional methods such as leaf-cutting, spikelet-thinning that lead to physical injury or physiological interference. The method provides a brand new approach and solution for thoroughly investigating source-sink relationship in rice, wheat, maize and other crops, and will play an important role in enriching crop source-sink theory and also promoting the development of the related disciplines.

The invention relates to the field of plant improvement, in particular of the improvement of yield for plants, by using a transgene containing the BETL9 promoter driving expression of the MRP1 protein.