The quality standards which are established pursuant to this chapter shall be considered as a grade under Chapter 1 (commencing with Section 40501). If a marketing order is issued pursuant to Chapter 1 (commencing with Section 58601) of Part 2 of Division 20, which established uniform grading and inspection for dehydrating garlic and onions, then and so long as it is effective, the provisions of such marketing order shall control and the provisions established by regulations are ineffective as to garlic or onions which are covered by such marketing order.