Grain yield, milling and breadmaking quality responses to foliar diseases in old and modern Argentinean wheat cultivars

Foliar diseases limit yield and modify the quality of the bread wheat. Due to genetic improvement reduced source:sink ratio, it is possible to speculate that the diseases infections penalize yield more in modern than in old cultivars, affecting differentially quality commercial and milling properties. The objective of this work was to analyze the changes in yield and quality of bread wheat due to the presence of foliar diseases in old and modern bread wheat cultivars artificially inoculated with Puccinia triticina, compared to a control plots protected with fungicide. Foliar diseases penalized yield due to reductions in the number of grains in all cultivars. Protein in grain-flour, wet-dry gluten and sedimentation were reduced when Pyrenophora tritici-repentis was the main pathogen, while Puccinia triticina only reduced the protein content in grain. Modern cultivars shower greater decreased proteins in grain-flour and gluten than old cultivars, probably associated with higher yield and lower source:sink ratio respect to the old cultivars. The changes in dough rheology and breadmaking quality, as a consequence of foliar diseases, were not as marked or as consistent as observed on milling quality, and the magnitude and direction of those effects were not as clear as those observed in milling quality.