ارزيابي مقاومت نسبي تعدادي از ژيوتيپ هاي چغندرقند نسبت به پوسيدگي ريزوكتونيايي ريشه و طوقه

Evaluation of relative resistance in some selected sugar beet genotypes to Rhizoctonia root and crown rot

Virulence level of 7 isolates of Rhizocwnia so/ant belonging to Anastomosis Groups (AG) 4 and 2-2, were compared by inoculating them on cultivar IC. Thereafter- the selected highly virulent isolate belonging to AG2-2 was used for evaluation of resistance in 20 selected sugar beet genotypes to R.solani. Ten-weeks-old plants of different sugar beet genotypes were inoculated with infected corn kernels. Experiment was conducted in completely randomized design with 3 replicates in greenhouse condition. Each replicate included 200 pots, one plant in each, The rate of infection for each plant was measured using 0-7 scale, and Disease Severity Index (DSI) was calculated for each treatment. The results showed that ET5, F-20278. BP2, and 41RT were resistant. to Rhizoctonia root and crown rot.