Foxtail millet (Setaria italica) is an important crop species and an emerging model plant for C₄ grasses. However, functional genomics research on foxtail millet is challenging because of its long generation time, relatively large stature and recalcitrance to genetic transformation. Here we report the development of xiaomi, a rapid-cycling mini foxtail millet mutant as a C₄ model system. Five to six generations of xiaomi can be grown in a year in growth chambers due to its short life cycle and small plant size, similar to Arabidopsis. A point mutation in the Phytochrome C (PHYC) gene was found to be causal for these characteristics. PHYC encodes a light receptor essential for photoperiodic flowering. A reference-grade xiaomi genome comprising 429.94 Mb of sequence was assembled and a gene-expression atlas from 11 different tissues was developed. These resources, together with an established highly efficient transformation system and a multi-omics database, make xiaomi an ideal model system for functional studies of C₄ plants.

谷子（Setaria italica）是重要的农作物品种，是C ₄草的新兴模式植物。然而，谷子的功能基因组学研究具有挑战性，因为它的世代时间长、体型较大且难以进行遗传转化。在这里，我们报告了小米作为 C ₄模型系统的快速循环迷你谷子突变体的开发。由于小米的生命周期短，植株体型小，与拟南芥相似，一年可在生长箱中生长五到六代。光敏色素 C ( PHYC ) 中的点突变) 基因被发现与这些特征有关。PHYC编码光周期开花所必需的光受体。组装了包含 429.94 Mb 序列的参考级小米基因组，并开发了来自 11 个不同组织的基因表达图谱。这些资源，加上已建立的高效转化系统和多组学数据库，使小米成为C ₄植物功能研究的理想模型系统。