A new approach to crop breeding, which focuses on how crops interact with each other and the environment, could unlock hidden genetic potential and help farmers cut down on fertilizer use. Researchers at the University of Queensland suggest that selecting crops based on how they affect future crops, rather than just their own yield, could offer major benefits. This method is based on the idea that each crop leaves a "legacy" — changes in soil nutrients, water, structure, and microbial life — that can influence the next crop grown on the same land. Traditionally, crop rotation — the practice of alternating different crops in a field — has been used to improve soil health and productivity. However, the genetic factors that make some rotations more beneficial than others have not been well understood by plant breeders. Dr. Millicent Smith from the Queensland Alliance for Agriculture and Food Innovation says that by treating crop rotation as a genetic question, rather than just a farming practice, breeders can develop crops that work better together. In a groundbreaking experiment, Smith’s team tested over 300 different types of mung beans and then planted the same wheat variety in each plot. The results were striking: some mung bean varieties increased wheat yields by 45%, while others cut wheat yields in half. This shows that the genetic makeup of a crop can have a significant impact on the performance of the next crop in the rotation. The research team believes this opens the door to breeding crops that are more compatible with each other, improving overall system productivity. Plant breeder Lee Hickey explained that certain parts of the mung bean genome are linked to how well the following wheat crop performs. Some of these genetic factors can be conflicting — traits that make a crop high-yielding may leave fewer nutrients in the soil for the next crop. By selecting for both yield and soil benefits, the team found that both crops could be improved simultaneously. This suggests that breeding for system-level productivity — not just individual crop performance — is possible. The researchers stress that more testing is needed to confirm these findings across different regions and crops. While the results are promising, the biological mechanisms behind the effects are still not fully understood. The team plans to investigate this further, using tools like drones, genomics, and advanced computing to analyze crop interactions at a large scale. They believe this is an exciting time to shift the focus of breeding from individual crops to the entire farming system, helping to create more sustainable agricultural practices.