DOI: 10.1002/ppp3.70275 ISSN: 2572-2611

Evolution of photoperiod insensitivity drove the westward expansion of broomcorn millet

Giedre Motuzaite Matuzeviciute, Michael Kempf, Margaux L. C. Depaermentier, Harriet Hunt, Kristina Jaskune
Show PDF Cite

Social impact statement

This research highlights how ancient farming communities adapted crops to challenging environments, enabling the spread of agriculture across Eurasia. By demonstrating that broomcorn millet evolved reduced sensitivity to day‐length, the study explains how this crop could support food production in regions with short growing seasons and long summer days. These findings deepen understanding of human resilience and environmental adaptation in prehistory. The study also has modern relevance, as identifying traits linked to climatic flexibility may support the breeding of resilient crops for northern regions affected by climate change. Integrating archaeology and plant science provides valuable perspectives on sustainable agriculture and future food security.

Summary

Broomcorn millet ( Panicum miliaceum ) was among the earliest domesticated crops to spread widely across Eurasia after its origins in northern China around 6000 BCE. Archaeobotanical evidence shows that by the Bronze Age, its cultivation had expanded through Central Asia into eastern and southeastern Europe, reaching the eastern Baltic. Yet broomcorn millet is a short‐day plant, and at northern latitudes extended summer daylight can delay flowering and reduce seed production. Here, we test whether the westward and northward expansion of broomcorn millet was underpinned by the evolution of reduced photoperiod sensitivity.

We conducted long‐day cultivation experiments on 188 millet genotypes collected across Eurasia, grown under both controlled artificial light and natural long‐day conditions at 55°N. Heading time, growth patterns, biomass and yield‐related traits were recorded to evaluate variation in photoperiod response.

Results revealed strong geographic patterning. Most genotypes from East Asian monsoon regions remained highly sensitive to day‐length, heading very late or failing to head under long‐day conditions. In contrast, many genotypes from Central Asia, Siberia, and Europe headed earlier and produced viable seeds, indicating reduced photoperiod sensitivity.

These findings indicate that photoperiod insensitivity was a key postdomestication adaptation enabling millet to spread westward and northward into regions with shorter growing seasons and prolonged summer daylight. Such adaptive mechanisms offer insights into ancient agricultural resilience and may inform the development of climate‐resilient cereals for northern agriculture.

More from our Archive