In Dutch it's Turkije - there's a j in between ("ij" makes a single sound, and the "e" is another sound). "Turkie" would sound weird in Dutch too and it's not Dutch spelling, though I guess it looks like it.
According to Wikipedia, the Pennsylvania Dutch are actually from southern Germany, and have no connection to Holland or Dutch.
Oh I didn't get that "Penn." part, that explains.
Sorry. I was too tired to spell Pennsylvania. =P
Türkie might be a misspelling of Türkei (German) or Türkiye ( Turkish).