Assessment resistance of sugar beet pollinator S1 lines to charcoal root rot

Resistance of 16 S1 pollinator lines derived from two populations with resistance to Rhizoctonia and drought، six cultivars and an open pollinator population were evaluated to a highly virulence isolate of Macrophomona phaseolina، causal agent of charcoal rot of sugar beet in greenhouse condition. Evaluation of the cultivars and lines was carried out in separate experiments. Tooth pikes were used as inoculums. Four-six month plants were inoculated and one month after inoculation، severity of root rot was estimated using a 1-9 standard scale. The results showed different levels of resistance among cultivars and lines. Cultivars Shirin and Jolgae were very susceptible to the disease. Cultivars Flores، Dorothea، Rasta، B8662 and B8618 lines as well as SB19 population were classified in the resistance category with 1 to 3 disease severity indices. Drought resistant lines had a disease severity index ranging from 4. 56 to 7. 36 and were grouped in a susceptible category.