Genetic Analysis of Resistance to Wheat Fusarium Head Blight in Morvarid (resistant) × Falat (sensitive) Cross

Fusarium head blight disease caused by Fusarium graminearum is one of the most important and destructive diseases of wheat in warm and humid zone. The importance of this disease is to reduce the yield and accumulation of mycotoxin in the harvested grains from infected heads, which are dangerous to humans and animals. Production of resistant varieties with using genetic resistance sources is the most effective method of sustainable control of this disease. To study the inheritance of resistance-controlling genes in cv. Morvarid, the resistant cv. Morvarid, was done cross with susceptible cv. Falat, and generations of F1, F2, BC1 and BC2 were produced. Resistance components include the area under the disease progress curve (AUDPC), the relative area under the disease progress curve (rAUDPC) and the final severity infection (FSI), was recorded. Parents and generations were planted in a randomized complete block design with three replications. Parents and generations were inoculated at the adult plant stage by a mixture of Fusarium head blight isolats at the Gorgan Research Station. Analysis of variance showed significant differences among generations for measured traits. The average degree of dominance was approximately equal to unit (one) for all traits, indicating dominance genetic control. Epistasis interaction effects of additive × dominance, dominance × dominance were significant for the all traits. Broad-sense (0.45- 0.56) and narrow-sense (0.37-0.48) heritability was estimated as moderate, indicating the important role of additive effects and dominance in genetic control of these traits. The number of segregating genes for measured traits 1 to 7 genes was estimated. Since Morvarid Cv. is currently the most commercially resistant cultivar to Fusarium head blight, due to the additive effects of resistance genes in controlling these traits, selection can be applied to improve these traits in the early generations of this cultivar.