中文摘要：

在依赖结构不对称的渠道关系中，契约治理机制能否有效抑制关系双方的投机行为尚未得到现有研究的关注。针对这一理论问题，本研究以契约型农产品渠道为背景检验了契约治理机制对渠道关系双方（农户与收购商）投机行为的影响作用，并进一步考察了市场不确定性和政府支持两个重要环境变量的调节作用。研究发现，即使是在依赖结构高度不对称的渠道关系中。明确的契约对渠道关系双方的投机行为都具有直接的抑制作用。同时，市场不确定性和政府支持对依赖结构不对称的关系双方的投机行为存在不同的调节作用。具体来说，市场不确定性会强化契约明确性对农户（依赖程度较高的一方）投机行为的抑制作用．但在契约明确性与收购商（依赖程度较低的一方）投机行为之间的调节作用并不显著。此外，政府支持会削弱契约明确性对农户投机行为的抑制作用，但会加强契约明确性对收购商投机行为的抑制作用。文章最后对研究结果的理论意义进行了讨论，并给出了相应的管理建议，指出了未来的研究方向。

英文摘要：

In channel relationship with dependence asymmetry, it remains unanswered whether contract governance could curb the opportunistic behavior of two parties in the relationship. In the context of contractual channel of agriculture produets, this study investigates the effect of contract governance on the opportunistic behavior of two parties（farmer and buyer）in channel relationships, as well as the moderating role of two important environmental variables, market uncertainty and government support. Findings show that, despite of dependence asymmetry, explicit contract can directly curb opportunistic behavior of two parties in channel relationships. Moreover, the market uncertainty and government support have different moderating roles. Specifieally, market uncertainty strengthens the effect of explicit contract on farmer（the more dependent one）opportunistic behavior, but it does not moderate the effect of explicit contract on buyer （the less dependent one）opportunistic behavior. Additionally, government support weakens the effect of explicit contract on farmer opportunistic behavior, but strengthens the effect of explicit contract on buyer opportunistic behavior. Finally, this paper includes a discussion of the research findings, corresponding managerial suggestions and the future research directions.