So, I had this suspicion that..
Dalamud Popotoes are to Chives as
Royal Kukuru is to Glazenuts.
I think I was right. Dzemael Tomato + Dalamud Popoto = Chive
http://i.imgur.com/CTPlopA.png
3 out of 3 on my attempts.
So Pearl Sprouts aren't required to make Chives (but Pearl Sprouts are a lot easier to get).
I suspect that crossing the popotoes with leek would've had the same result.
Crossing sprouts with either tomatoes or leek results in nothing, so far, similar to how apricots with old world figs give nothing.
Not exactly pioneering info, but just food for thought.