The Festival of Shavuot (Pentecost) is another name for the Festival of Weeks. Exodus 34:22 says, "And thou shalt observe the feast of weeks, of the firstfruits of wheat harvest, and the feast of ingathering at the year's end." Also according to the article called The Festival of Shavuot: Bringing the Firstfruits to the Temple at http://www.templeinstitute.org/shavuot.htm there were two loaves of wheat bread (not barley bread) baked with leaven that are waved up in the air. Please read the entire article, but the part about the 2 loaves of wheat bread baked with leaven begins further down the page under the heading of The Twin Loaves and continues on down from there. Although the Feast of Weeks comes at the end of the barley harvest, it is the firstfruits of the new wheat harvest that are baked in loaves of wheat bread with leaven that are waved up in the air. Here is another article at http://www.templeinstitute.org/shavuoth/opening.htm that states the same thing.