The study looked at how wheat has been improved over time to produce more grain. They grew 32 wheat varieties from different years and found that newer varieties had higher grain yield. The leaves of the plants got bigger and produced more energy for the grain. Newer wheat varieties also accumulated more dry matter before and after flowering, which helped increase grain yield. By improving the growth before flowering and the amount of energy transferred to the grain, wheat breeders can create varieties that produce more grain in the future.