Investigation of Resistance Selected Varieties and Relationship with Increase Grain Yield by Fusarium head blight in Wheat Cultivars from Northern Iran

Fusarium head blight of wheat with causal agent of fungus Fusarium graminearum is one of the most common diseases affecting wheat. Fusarium as one of the major wheat diseases makes a significant loss on wheat yield and quality globally. Northern Iran, due to the distinct conditions of humidity and temperature is susceptible to Fusarium head disease. One of the most efficient ways to control this disease is the use of resistant, genetically modified cultivars. The annual screening of plant cultivars offers useful information on resistance of cultivars to Fusarium head disease for researchers.

In this study 21 cultivars of common wheat including irrigated and rainfed plus three resistant cultivars and susceptible in a complete block design with three repeat in two different environment were cultivated in Gorgan University educational farm in 2016. One of the settings was the disease-induced and the other was not disease-induced. In the stressed setting artificial contamination was induced with spore suspension and in the non-stressed setting Falcon fungicide was used to control the disease. Each wheat cultivar was planted on a 4.5 meter line. Lines had a 30 cm distance from each other and seeds had a distance of five cm. In this experiment, fresh fungi suspensions with a concentration of 1×108 macroconidia per milliliter were used. Fusarium spore suspension was applied to spikes at the beginning of the flowering period at the onset of the emergence of anthers. After spore suspension application, the disease indices including, the incidence of disease, severity of disease and disease index, and after harvesting, the percentage of infected seeds and performance indicators were measured.

Based on the results of analysis of variance, a significant difference between the cultivars tested at the probability level of 1% for incidence, severity of disease and percentage of contaminated grains was observed. Analysis of yield data using analysis of combined experiments showed that the cultivars Qaboos, Aftab and Layn 17 among the rainfed wheat cultivars, and Morvarid in irrigated cultivar, were the best cultivars in response to Fusarium head blight. Among the cultivars studied, Qaboos and Aftab had the least yield loss and were suitable for cultivation in areas with Fusarium head blight epidemy.

The results of this study showed that the occurrence of a biotic stress such as Fusarium head blight negatively affects the grain yield, the more resistant cultivars have lower yield loss. The results of this research can be used as a source for resistant genotypes for corrective actions. Qaboos and Aftab cultivars are introduced as resistant cultivars in areas with high risk of Fusarium epidemy. The Ehsan cultivar is a coarse grain cultivar and has a good yield in a disease-free environment, perhaps it can be found to be suitable for cultivation in areas with low humidity