In the oats study, researchers found that when looking at how different oat varieties perform in various locations, the factors affecting yield were different for certain parts of the oat plant compared to the overall grain yield. This was because the way these different parts interacted with each other affected the final grain yield, not just their individual performance. Basically, understanding how each part of the oat plant works together helped predict the grain yield better, rather than just looking at them separately. This may be useful for farmers in choosing the best oat varieties for different locations to improve overall yield.