Evaluation of resistance of sugar beet commercial varieties to rhizomania disease under field conditio

Rhizomania is one of the most devastating diseases of sugar beet. In this research, 69 cultivars were cultivated in rhizomania disease condition in the Fars and Khorasan Agricultural and Natural Resources Research Centers. Cultivars assessed for disease intensity, were also studied for qualitative and quantitative traits. In 49 cultivars experiment done in Shiraz, Brigitta, Silenta, Pauletta , Rasta, Flamingo , Baltazar, 5K43, 7K05, 7K03,7R19¡7R26 , 7R27,Isella, BTS851, BTS853, BTS792, HI0549 and FD0823 cultivars produced higher root yield (RY) and white sugar yield (WSY) and HI0511, Dorhill, HI0590, Qualita, Imperial, Kavkas, BTS852, FD0718, Antek, FD0821 and FD0822 cultivars produced higher WSY compared to control resistant cultivar (Dorothea) and were classified in one group. In 20 cultivars experiment done in Shiraz, Dioneta, Ivano and Tous cultivars and 20507*SHRO1-P.12,20507*SHRO1-P.13, 20507*SHRO1-P.20 ,20507*SHRO3-P.2, 20507*SHRO3-P.26, (7112*436)*(20543*FC709) and (7112*436)*(20448*Doro) hybrids had higher RY and with resistant cultivar (Dorothea) were classified in one group. Disease score (assessed on a 1-9 scale) indicated that the highest level of resistance was found in the above mentioned cultivars. In 49 cultivars experiment done in Khorasan, BTS852 , 7R26 , 7K05 ,BTS851 , 7K03 , 7R19, Qualita , Dorothea ,DS4047 , 7R26 and 7K03 cultivars produced higher RY and WSY. According to the disease score,the mentioned cultivars had the lowest score (the highest resistance to rhizomania disease). In 20 cultivars experiment done in Khorasan, Dioneta, Ivano and Dorothea cultivars produced higher RY and WSY. Also, in this trial 20507*SHR02-P. 20507 æ 9 *SHR02-P.4 hybrids showed desirable results and according to the disease score, had the lowest score (the highest resistance to rhizomania disease).