Increasing nitrogen levels in wheat crops can lead to higher grain yield and better quality for making bread. Researchers studied six wheat populations and found that population C6 had the best flour protein and lowest ash content, along with high yield. Selecting for larger kernel size improved yield in some populations but reduced flour protein in others. Grain protein concentration increased in later generations, showing a positive link with yield. Under high nitrogen levels, populations C6 and C4 had the highest unique protein bands. Overall, higher nitrogen levels increased the amount of certain proteins in wheat grains, but different populations responded differently to the nitrogen levels.