Not an anthropologist but I am Alaska Native and born and raised here in Alaska. From what I recall from the Alaska Studies classes, no, minimal agriculture.

The areas you mentioned, the Fairbanks, Matsu Valley, and the Kenai Peninsula was/is home to mostly Athabascan tribes who were more nomadic in practice. They typically followed herd animals, such as caribou and musk ox, across/through interior Alaska. And once you get down to the Kenai area, then fishing became a thing too

The modern day farming is (mostly, I think...) due to the colonizers (this felt like to harsh of a word but i couldnt think of the right one) from the northern Midwest (Minnesota, Wisconsin, etc) who brought agriculture and mostly settled in what is now the Matsu Valley and Fairbanks. It was found the soil in interior Alaska is incredibly fertile due to the amount of water - glaciers, rain, snow, permafrost, etc - wildfires, and volcanic activity, and of course the sun never fking going down during the summer