Reaction of Improved Sesame Lines and Cultivars to Fusarium Wilt at In vitro and Greenhouse Conditions

Fusarium vascular wilt of sesame is one of the destructive soilborn diseases of this crop in Iran and worldwide. Infected tissues of sesame were collected from the experimental field of Seed and Plant Improvement Institute in Karaj, then pieces of stem and roots were excised and cultured on the media. Fusarium oxysporum f.sp. sesame (Fos) was recovered frequently from the tissues up to 81% of the isolated fungi, while F. solani was isolated in some few cases. Pathogenicity of the isolates was evaluated on the SNA Petri plates in the lab condition. The disease resistance assessment carried out using two different methods. For the laboratory method, the SNA plates were used for 12 cultivars and lines. The line Jiroft-13 had the highest level of disease resistance in this test. In the second method of inoculation, roots of the seedlings of 26 cultivars and lines were dipped into the spore suspension for 5 minutes and then planted in pots in greenhouse. Disease severity was recorded after 15 days using a 1-5 scale. Observations of each genotype was statistically analyzed using non-parametric Chi-square test. None of the genotypes were immune to the disease. Among the less infected genotypes, Moghan 19, Shahed-e- Gijuye, Mahali Moghan Shahed, Hindi-11, Moghan 13, Mahalli Moghan and B5γM7 showed considerably low infection, so regarded as moderately resistant cultivars.