Very small ones, low fat. At that age, even using kibble bites. Treats are more the ceremony than the treat. But you can boil chicken and cut into tiny pieces. I'd wait a bit older to try tiny bites of apples. US made and sources treats, again break into small bites. And use happy YES and petting for rewards as much as possible.
I have been using "Mini Train-Me!" and our basenji LOVES THEM! We have the chicken flavor but their are other flavors as well! you can find it on amazon and Walmart. It is in a yellow package.
While their products are "manufactured" in the US, they are not sourced here. I never give my dogs anything that is not clearly from US, Canada, New Zealand or safe meat producers.
A good hint is that if they don't SAY they are US Sourced, they aren't.
We are bringing home our first Basenji in a few weeks, and found Zuke's treats which is what we'll be using. All natural and US or New Zealand sourced.
I like Zukes. Also Butler Lean Treats Nutritional Rewards for Dogs (Henry Schein, but actually made by Biljac who says USA source meat).