The researchers studied 130 types of wheat to find which ones are best at using nitrogen efficiently. They wanted to see how much wheat each plant produced and how well they used nitrogen. They found that some wheat types were much better at using nitrogen than others. The wheat that used nitrogen well had fewer useless parts, used nitrogen early on, and reused it effectively. Two types of wheat, Sheng CXK027-4 and Liangmai 4, had much higher yields and nitrogen use than another type, 694.