Wheat -The Food of Knowledge
In the debate among the Talmudic Sages (Sanhedrin 70b) as to what exactly was the food of the Tree of Knowledge from which Adam ate, it is the position of Rabbi Yehuda that it was wheat. This is a sharp departure from the positions of his colleagues who identify that tree as one which bore grapes or figs.
The basis of Rabbi Yehuda’s compulsion to identify this sinful food as wheat, despite the obvious difficulty of connecting wheat with a tree, is the fact that this tree is described by the Torah as one whose food imparts knowledge. A baby, he points out, does not have the understanding to say the words “father” and “mother” until it eats wheat. It is logical, therefore, to assume that only food which imparts such understanding in a child could be considered the food which gave man the knowledge to distinguish good from evil.
Wheat was the principal ingredient of the flour offerings in the Beit Hamikdash. It, and its subspecies spelt, are mentioned (Pesachim 35a) as ingredients which qualify for use in the matzah we eat on Pesach to fulfill our mitzvah.