自上世纪90年代以来，通过增加收获指数的途径来提高小麦产量潜力的难度越来越大，主要原因是对小麦同化物分配的生理和遗传机制缺乏系统的认识。本项目拟在陇东旱地雨养农业区选择不同时期育成推广的冬小麦品种为研究对象，设置大田试验，采用剪叶、小穗移除、群体遮阴等方法人工改变源库关系，系统研究不同类型旱地冬小麦品种同化物累积分配、小花（原基）发育动态、穗部光合的变异规律，解析同化物分配、小花发育、穗部光合与产量构成要素（粒重和穗粒数）之间的内在联系，以期明确陇东旱地冬小麦品种产量提高的同化物分配规律和小花发育机制。从组合配置、田间选择、管理实践等方面提出陇东旱地冬小麦品种产量进一步提高的有效途径和今后改良的方向。研究结果将为陇东乃至西北旱地雨养农业区旱地冬小麦的高产、高效选育提供理论依据和技术途径，对深化和拓展旱地冬小麦产量潜力提高的生理机制有重要的理论和现实意义。

In the context of attempting to substantially raise wheat yield potential, great attention of food production have been focused on how to understand the physiological and genetic basis of assimilation partitioning when there has been no systematic genetic progress in harvest index (HI) since the early 1990s. Consequently, field experiments will be designed by selecting different dryland winter cultivars released in different stages in Longdong semi-arid rainfed agricultural area. By means of defoliation, canopy shading and spikelet removal, systematical research will be aimed at investigating the variation characters of assimilation partitioning, floret development and ear photosynthesis. Research will also analyze deeply the intricate relationships among assimilation partitioning, floret development and ear photosynthesis and between those and yield determining factors (grain weight and seed number per ear). The objective of this study is to make clear the mechanisms of spike development and assimilation partitioning related to yield improvement of winter wheat cultivars planted in dryland. Yield improvement strategies of those cultivars will also be established from the views of cross combination, field selecting and management practice. Results will be an important theorical proof to enhance selecting efficiency of winter wheat in Longdong and even Northwest arid rainfed agricultural area. Moreover, it is also meaningful to deepen and broaden the physiological mechanism associated with yield potential improvement of winter wheat planted in dryland.