Response of some Native and Improved Genotypes of Sesame to Damping off Agents under Field Conditions

Breeding for resistance to damping off is one of the main aims in sesame breeding scheme. Since the most important causal agents of damping off are soil- borne fungi, using resistant cultivars is the best strategy to control this disease. The fungi, Macrophomina phaseolina (causing charcoal rot) and Fusarium oxysporum f.sp. sesami causing root (causing crown and stem rot of sesame) are the most important causal agents of damping off in sesame in Iran. In this research for screening of sesame germplasm to damping off agents, 81 native and improved genotypes of sesame were cultivated in a farm infested by infected plant debris. The experiment was conducted as simple lattice with two replications during 2002-2004 growing seasons at the Research Farm of Seed and Plant Improvement Institute, Karaj, Iran. The results showed that four genotypes of Moghan 17, Moghan 19, Moghan 3 and Iraqi 2 had the highest level of resistance to damping off in field condition. Sixteen genotypes grouped as moderately resistant, 15 genotypes as moderately susceptible and the rest grouped as susceptible or highly susceptible ones.