In all seriousness, you can make "bread" from damn near any grain if you're persistent enough and grains of various types (and small fruits, i.e. berries) can grow basically anywhere. It's large fruit and vegetables that tend to require easy mode to grow (which makes sense since they spend proportionally more resources growing that the fruit they produce). I'm not sure what's native to tibet but I assume they have some sort of wheat-like grass that can be farmed and provides grain for bread.
In all seriousness, you can make "bread" from damn near any grain if you're persistent enough and grains of various types (and small fruits, i.e. berries) can grow basically anywhere. It's large fruit and vegetables that tend to require easy mode to grow (which makes sense since they spend proportionally more resources growing that the fruit they produce). I'm not sure what's native to tibet but I assume they have some sort of wheat-like grass that can be farmed and provides grain for bread.