We learn on 84A , that Bekurim are brought from the 7 Minin, that eretz Yisroel are praised with. Among them are Wheat and Barley. Is rye, oats, and spelt included among the 7 Minin, since we had a Braisa on 70A( bottom) that states, that these are subcategories of Wheat and ]Barley ?
The Har Tzvi (O.C. 1:108) understands that whether or not they are brought as Bikurim is actually an argument between the Maharsha and Pnei Yehoshua in Pesachim (36b). [See Har Tzvi at length, also regarding whether or not they are considered Shivas ha'Minim in Hilchos Berachos.]
All the best,
Yaakov Montrose