Root rot disease which is caused by Fusarium solani is one of the most devastating soil-borne diseases of safflower in Isfahan, Iran. The early symptoms of root rot appears on lower leaves which exhibit as yellowing and wilting and in severe cases the plant will die. In this study, suspected plants containing the disease were collected from safflower farms in Isfahan and root and crown of infected plants were cultured on potato- dextrose- agar (PDA). Identification using conducted on 11 cultivated and 11 wild safflower genotypes using a completely randomized design with three replications. Plants were separately inoculated at seedling and right before flowering stages and evaluated for root rot resistance. Genotypes of wild safflower C. oxyacanthus showed relatively high resistance while the cultivated genotypes of C. tinctorus revealed various levels of resistance to this disease . For the cultivated genotypes, a Canadian improved cultivar “Saffire” was the most sensitive genotype. Other genotypes in this group including “Esfahan 14”, “IL”, “C111”, “S231”, “E1431”, “Arak 2811”, “C4110” and “C121” all showed a similar reaction and were relatively sensitive to the disease. Genotypes of wild C. lanatus exhibited high mortality rate indicating lack of resistance genes in this species. Comparison between the two inoculation stages showed diverse reactions of cultivated and wild C. oxyacanthus genotypes at both stages. Among cultivated genotypes, highest mortality was observed when plants were inoculated at four-leaf seedling stage. Mortality was not observed among the genotypes of wild C. oxyacanthus , and compared to the cultivated genotypes, wild plants showed more resistance both at seedling and before flowering stage to the disease. Based on the results of this study, genotypes of wild C. oxyacanthus are considered a useful source of resistance genes to root rot disease. Genotypes of this species may be used as resistant parents in breeding programs to transfer resistance genes to cultivated lines. Keywords : Safflower, Fusarium solani , wilt, Root rot, Resistan
