علیرضا پورمحمد

In order to evaluate the resistance of 16 sugar beet hybrids to rhizomania, an experiment was carried out based RCBD with four replications. The Anova showed significant differences between the assessed hybrids for most traits except yellow color, infection severity and storage root yield (RY). The Pearson correlation coefficients between sodium with potassium and nitrogen elements and potassium with nitrogen were positively significant. The correlation between white sugar yield (WSY) with impurity related traits and alkalinity was negatively significant, and its correlation with sugar content (SC), molasses, white sugar content (WSC) and extraction coefficient of sugar (ECS) was positively significant. Cluster analysis by the Ward’s method classified hybrids into two main groups. Hybrids 1, 2, 3, 4, 5, 6 and 7 were placed in the first cluster and the second cluster included the other hybrids. In the first group, the content of sodium, potassium and nitrogen, RY, molasses sugar, infection severity and yellow color were above the total mean. The percentage of these elements is directly related to the amount of infection, which the results of this research confirms. Cultivars with partial resistance to rhizomania were characterized not only by a higher RY and sugar content but also by a lower sodium and potassium content. In this research, for the WSY, the second cluster hybrids also had a higher value than the total mean. Due to the low level of infection incidence in this cluster, the general recommendation is to use the second cluster hybrids, which have less infection and high white sugar yield. This indicates that developing sugar beet hybrids that are resistant to disease is the most efficient measure of controlling the disease.