Why do you have to cut off branches that sprout below the graft?

Branches that sprout below the graft on a grafted plant are typically removed to ensure that the energy and nutrients are directed to the desired cultivar above the graft. These shoots, often referred to as "suckers," can compete with the grafted variety, potentially diminishing its growth and fruit production. Additionally, they may introduce undesirable traits from the rootstock, which can negatively affect the plant's overall quality and performance. Regular pruning of these branches helps maintain the health and integrity of the grafted plant.