Evaluation o rhizomania and root rot disease damage in autumnal and spring cultivation o sugar beet

Rhizomania is one o the most destructive diseases aecting sugar beet in Iran. Itleads to a severe loss in terms o yield root and sugar. This disease cannot control by chemical methods, but with the change in planting time, there is the possibility o damage. Investigate the eect o rhizomania disease in the autumn sowing and compare it with the spring sowing. With this purpose, ive commercial cultivars (resistant and susceptible) were planted in a ield inected to rhizomania disease. rom each cultivar were planted in autumn (November) and spring (October) 15 samples (5m2 area) harvested randomly.Root yield was signiicantly dierent (P0.05) in the two autumn planting times. The results showed that sugar beet harvest; autumn in July (regardless o the time o culture) increased the root yeild, sugar content and white sugar yield. Analysis o variance o the data showed that the interaction o time at harvest *planting time in autumn in statistical probability level o ive percent, there was signiicantly dierence in o the important traits such as root yeild,sugar content,white sugar content. The results o this study showed that sugar beet cultivation in 15 September and its harvest in 1 July is the highest root yield in the hectar. Between the time the culture (spring and autumn) signiicant dierences (P 0.01) were observed in triats o root yield o sugar content, the sugar purity, disease index o rhizomani and the concentration o virus in the sugar beet root. The results o this study showed that the cultivation o autumn increased root yield mean,sugar content and purity. The overall result is that culture-sensitive varieties cannot accounted or in the spring o disease in the inected arm in terms o economic but the cultivation o this variety or any variety that is resistant to bolting is recommended in autumn.