evaluation of resistance and response of grain yield and yield components of spring wheat genotypes to fusarium head blight

fusarium head blight (fhb) is an important disease in wheat worldwide that reduces grain yield, quality as well as contaminates grains to the mycotoxins. thirty spring wheat genotypes including 28 bread wheat and two durum wheat genotypes were evaluated for fhb under a randomized complete block design with three replications. grain yield and its components were evaluated by using two environmental conditions including disease-free environment (created by tilt fungicide) as a control and disease-infested environment by hand sporing. the disease incidence (dic), disease severity (dsv), fusarium damaged kernels (fdk) and stress susceptibility index (ssi) were evaluated as four types of resistance indices. combined analysis showed the significant reduction of grain yield via grain weight that was affected by fhb. the bi-plot diagram for isk (incidence-severity-kernels) and ssi (stress susceptibility index) showed that the falat cultivar was the most susceptible and sumi3 and frontan were two most resistant cultivars to yield reduction.