The researchers studied how a gene called Hd1 affects when rice plants flower. They looked at different types of rice from China and found that changes in Hd1 are linked to when the plants bloom in short days. By comparing the genes of wild and cultivated rice, they discovered that Hd1 likely evolved in different groups of wild rice and was domesticated multiple times. The presence of specific Hd1 variations in Southern China suggests it may be a key area where rice was first domesticated. This research sheds light on how Hd1 has been important in the domestication of rice.