Old durum wheat varieties were studied to see how they grow and make bread with different levels of nitrogen. The old varieties did just as well as a modern one, even with less nitrogen. More nitrogen didn't make the wheat grow more or have more nitrogen in it, but it did increase the protein in the grain. This made the bread better, even though the gluten index went down. The protein and gliadin in the grain were important for good bread. Some old varieties, like Calabria and Cappelli, were able to make a lot of wheat and high-quality bread. This shows that old Italian durum wheats have a lot of different qualities and are good for farming with less chemicals.