No, but if he makes himself for example completely dependent on Monsanto, he shouldn't have a business, because he's in practice an employee with all the financial responsibilities of a business and none of the benefits of having a business. And none of the benefits of being an employee either.
If your business model is to make yourself completely dependent on a single third party, then you shouldn't have a business.
The only way it would be possible for him to become completely dependent on Monsanto is if that company is allowed to monopolize the product categories it sells.
If your business model is to make yourself completely dependent on a single third party, then you shouldn't have a business.