That would make sense, since hauling massive amounts of food many light years between star systems is quite an undertaking.
HOI-style convoys confirmed?
So far I read nothing about modifiers for agrar worlds
Heck, you wouldn't need new ones. There are plenty of existing ones.
Farm subsidies, governors, tiles with food on them, slave bonus to food production, slave processing facility further increasing food output, and so on.
With global food, I could use exiting mechanics to make some real breadbaskets,
especially if I am a slave owning empire. Oh, I conquered some filthy xenos who live on a world with poor mineral content? Get in the fields and pick my potatoes, cretins!
EDIT: I completely forgot the currently pointless species trait that increases food.
You live on a world with 8 food tiles? Congratulations! You just "volunteered" for gene therapy to make you better at farming. It's like a dystopian version of Green Acres. You'll love it! It's the best!