By using the genealogy of hybrid rice, Mahsuri, developed in Malaysia by Japanese agronomists in the 1960s, this article tells a story of agricultural modernization in Asia that challenges the US-centered narrative of the Green Revolution. Cross-racial hybrid Mahsuri’s parent is Taichung 65 from colonial Taiwan, and its off-spring is irradiated Mahsuri Mutant. By highlighting the deep connection between colonial development and post-World War II technical assistance, the role of intra-Asia networks in crop improvement programs in Asia, and the agency of postcolonial Asian nations, this article critiques the ironies embedded in the mutant rice and in the concept of development.