关键词: 两系法, 两系法, 杂交稻, 杂种优势利用, 进展

Abstract: 【OBJECTIVE】The rapid decrease of agricultural space in Beijing has done great harm to the sustainability of agriculture development. Under such circumstance, studies of the possible space for agriculture in Beijing and how to use it reasonably are necessary. 【METHOD】Based on the analysis of influencing factors of agriculture development, Newton's theory of space as a guide, and Venn diagram as the display means, Beijing's agricultural development space was explored. 【RESULTS】Beijing's agricultural development space can be divided into two kinds of spaces and four subspaces, the former consists of the absolute space and the relative space, and the later comprises the reality space, the extensible market space, the extensible policy space and the cooperative development space. For different agricultural spaces, the content, feature and use directions are different accordingly. Measures should be carried out to stabilize the absolute space and to explore the relative space, at the same time, we also need to use the reality space efficiently, exploit the extensible market space, the extensible policy space, etc, to break through the restriction of agricultural resources in Beijing. 【Conclusion】The study can be beneficial to the protection and expanse of agricultural development space, and to promote 调和sustainable agriculture development of Beijing.