عنوان مقاله [English]
Using resistant cultivars is the best way to reduce damages caused by sugar beet root rot and rhizomania. In order to develop resistant cultivar to these diseases, sugar beet genotypes were evaluated under artificial inoculation to rhizoctonia and one of the pollinators was selected as the most resistant population to rhizoctonia (SB19) in 2003. Self-fertile lines and hybrids were derived from non-inoculated roots of this population in 2004 and 2005, respectively. Selected hybrids were compared in terms of yield in different regions for two years and also pollinator lines were evaluated in terms of resistance under micro plot conditions in Hamedan. Results showed that sugar yield of a hybrid that its pollinator was selected as Ekbatan cultivar’s pollinator was 10.2 t.ha-1 and decease index of its pollinator was 2.16. Average sugar yield of Ekbatan in infested and non- infested regions with rhizoctonia was 9.1 and 7.0 t.ha-1, respectively. According to the results of yield and resistance to rhizoctonia evaluation, 10 superior lines were selected. In order to obtain resistant hybrid to rhizoctonia as well as tolerant torhizomania, 18 hybrids were developed by crossing those 10 superior lines with some male sterile lines that were resistant to rhizomania. Yield comparison of the hybrids was performed in three different regions that were naturally infested with rhizoctonia and rhizomania during 2010 and 2011. Two-years averages of sugar yield for (7112*SB36)*S1-24 hybrid that was released as Ekbatan in those regions were 8.7, 8.9 and 9.3 ton.ha-1, respectively. In general, results indicated that yield and resistance of Ekbatan cultivar was similar to the foreign resistant cultivar. The time needed to reach 90% seed germination by Ekbatan was 80 hours that is faster than that for Flores and Jolgeh cultivars. This indicates the higher germination rate of this cultivar.