Experts and BHG readers answer.
orange tree fruits from suckers and not the tree
Thanks for writing. The rootstock (part of the plant below the graft) is usually much more vigorous than the grafted plant --- so those stems are probably stealing too much energy from your grafted variety for it to thrive. Consistently removing the suckers should help your grafted variety to thrive and bear delicious fruit.
---Justin, Senior Garden Editor, BHG.com