When wheat was introduced into China is explained as follows.

At present, the mainstream view is that wheat was introduced into China from West Asia through the grasslands of Central Asia about 5,000 years ago. Because wheat can't adapt to the temperate monsoon climate in the Yellow River basin, the drought in spring is the most deadly, so it has been introduced to the northwest until the Qin Dynasty, as early as the pre-Qin era, and even before the ancient Three Dynasties, the Shang and Zhou Dynasties took root in the Central Plains. However, in ancient China, wheat experienced a long period of silence, and it was not until the Tang and Song Dynasties that it really replaced millet in the north.