Macro- and Microscopic Characterization of Components of Resistance against Puccinia striiformis f. sp. tritici in a Collection of Spanish Bread Wheat Cultivars

Yellow (stripe) rust, caused by the biotrophic fungus Puccinia striiformis f. sp. tritici (Pst), stands as most serious wheat disease worldwide, affecting approximately 88% of world production. Even though yellow rust generally develops in cool humid weather conditions, expansion new races adapted to warmer climates threatens zones where severe P. epidemics were infrequent, such Andalusian cropping areas. In order characterize resistance mechanisms Spanish germplasm, our study evaluated 19 bread cultivars against under controlled conditions for percentage severity (DS) and infection type (IT). From this visual evaluation, 74% showed resistant responses with only five considered susceptible. Subsequently, macroscopic microscopic components identified through image analysis histological studies, respectively, six selected cultivars. Macroscopic parameters total pustule area affected (%), together early-aborted established microcolonies regarding plant cell death microcolony length (µm), capable differentiating quantitatively. Thus, these could be used a basis screening future breeding programs, complementary physiology, genetic biochemical studies plant-Pst interaction. Finally, seems first characterization collection conditions.