Development of diploid pollinators resistant to rihzomania in sugar beetύ

Three diploid rhizomania resistant populations were evaluated in infected condition in 2008 which resulted in selection of 150 resistant plants that were used to develop full-sib families in 2009. 111 families were chosen based on the seed weight of the single plants which were screened for resistance in infected nursery in Zarghan region in 2010. The trial was conducted based on RCBD with four replications and analyses were done based on average of roots infection in each plot. According to the results, 18 families were selected as resistant families 10 of which were crossed with different monogerm single crosses (five families with three single crosses and another five with one single cross) in 2011. The 20 monogerm hybrids were compared for resistance and also root and sugar yield along with two domestic and three foreign resistant checks and also one susceptible check in three infected areas including Mashhad, Shiraz and Miandoab in 2012. The trials were conducted based on RCBD with four replications. The traits such as number of plants after thinning, growth uniformity and leaves greenness were recorded during growth season. Roots of each plot were counted, weighed and sampled at harvest time and the samples were sent to Sugar Technology lab of sugar beet seed institute for quality analysis. According to the results, most of the new hybrids were better than domestic resistant varieties from resistance and also performance point of view. But compared to the foreign checks, only the hybrid (7112*SB36)*S1-88605 could compete with them in most regions without any significant differences. This hybrid was better than domestic resistant checks in all the regions and showed significant differences with them for root and sugar yield. The above mentioned hybrid can be used in complementary trials for new variety registration.