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.