Hadith.2064 - Abu Abdullah عليه السلام said:
"Whoever cannot find wheat or barley, it is sufficient for him to give in place of it wheat flour, spelt, emmer, or corn."
Additionally: "If a person is in the desert and cannot provide the Zakat al-Fitr, it is obligatory for him to give four ritls of milk as charity."
Moreover: "Anyone who consumes a specific staple food must give their Zakat al-Fitr from that staple food."