I would think that a 2 gallon bucket wouldn't be big enough for continued growth? The most common sizes i use and i have heard most people use is 5 gallon pots....
I could be wrong but from my very brief experience, the rocoto wants to get to a larger size before it really produces good amounts of fruit. Also the small size bucket may have something to do with the limited yeild... Time of the year it was planted, and general temperatures could have something to do with it also..
Just my thoughts.