How did champa rice expand to different regions?

Champa rice, a fast-maturing and drought-resistant variety, was introduced to various regions primarily through trade and agricultural exchanges in Southeast Asia, particularly during the Tang and Song dynasties in China. Its introduction was facilitated by the movement of merchants and farmers who recognized its agricultural benefits, leading to its cultivation in regions such as Vietnam and beyond. Additionally, the rice's adaptability to different climates contributed to its spread, enabling it to thrive in diverse environments and significantly enhance food security in those areas.