I live in nebraska and I have a well heated greenhouse what is the shortest banana for my greenhouse?
'Novak' super dwarf Cavindish as far as I know. Excellent suckering so easy to propagate too.
If you're growing for eating bananas, I'd recommend the Raja Puri variety. It will fruit around 5-6 ft, but can grow up to about 8 ft height if planted in the ground. In a pot, it probably won't be that big. They produce nice eating bananas and are regular bearer. It's good that you have a green house. If you wish to share a picture of your greenhouse, that would be nice.