Impact of managing yellow rust (Puccinia striiformis f.sp. tritici) by the use of fungicide sprays and resistant varieties on the physiochemical qualities of bread wheat

Yellow rust disease caused by Puccinia striiformis f. sp. tritici is one of the major threats to wheat production in Ethiopia. In this paper, the impact of yellow rust on the physical qualities of bread wheat was studied. For this purpose, combinations of four bread wheat varieties (Digalu, Hidase, Danda'a, and Honkolo) and two fungicides (Nativo SC 300 and Tilt® 250E.C.) were tested at two different hotspot areas (Albazar and Alicho) in the Silte Zone, Southern Ethiopia, under natural epidemics of the disease during the 2018 growing season. A randomized complete block design in factorial arrangement with three replications was used to set up the experiment. A significant (p < .01) increase in hectoliters weight and wet gluten content were observed due to the application of Nativo SC 300; however, grain protein content did not respond significantly (p > .01) at both locations. Wheat varieties with high yellow rust severity exhibited maximum values of area under the disease progress curve and physical quality loss percentage (%). The highly susceptible wheat variety Digalu exhibited the highest values of hectoliter weight losses (%), and the actual losses ranged from 5.5% to 29.5%. Except for grain protein content, there was a significant negative correlation between the values of terminal rust severity, average coefficient infection, and area under the disease progress curve and that of hectoliters weight and wet gluten content, with correlation coefficients ranging from −0.85** to −0.33**. It is possible to improve the physiochemical properties of bread wheat through the application of foliar fungicides by selecting the appropriate genotypes that have an acceptable level of resistance to yellow rust.