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Efficient field phenotyping for multiple disease resistance in a winter wheat panel

Kerstin Flath: Julius Kuehn-Institut

<div>Wheat is challenged by many diseases, among them yellow/stripe rust (YR) caused by <em>Puccinia striiformis</em>, stem rust (SR) caused by <em>P. graminis</em>, and Fusarium head blight (FHB) caused by <em>Fusarium</em> spp. are the most important. For reducing the use of pesticides it is important to breed cultivars for the market with multiple disease resistance (MDR). Our objective was to analyze the resistance of 36 commercially grown European winter wheat cultivars to YR, SR, and FHB in three individual and one combined field inoculations across seven (YR, FHB) and three (SR) Location x year combinations to evaluate MDR in an efficient way. Large variation among wheat cultivars was detected for YR, SR, and FHB resistance ranging from 0% to 48%, 0.8% to 80% and 10% to 51%, respectively, in the combined inoculation variant. Interaction between inoculation treatments (individual vs. combined) and wheat genotype was not significant (P>0.1) for each of the three diseases. Accordingly, correlations between both inoculation treatments were very high (R<sup>2</sup>=0.95-0.99). Several cultivars showed MDR to two or even three of the pathogens. In conclusion, resistance ranking among genotypes was not changed when plants were challenged with all three pathogens together. Substituting factorial inoculation trials by multi-pathogen inoculation makes it more efficient to select for MDR in practical breeding programs.</div>