Study on some morphological traits and quality and quantity of promising sugar beet hybrids resistant to rhizomaniaύ

This study was conducted to compare Morphological and quantitative and qualitative characteristicsof promised hybridsresistant to Rhizomania with Iranian and foreigncommercial varieties and introduction of superior hybrid/s. It performed during two years (2001-2002) in four areas includedKaraj (non infected), Mashad,Miandoab and Zarghan (infected). These areas were selected based on their history of infection. The experiment consisted of a randomized complete block design with four replications. In the first year (2001) nineteen monogerm diploid hybrids which were test crosses of full sib families with two single crosses were evaluated for resistance to rhizomania. But in the second year, 14 of them were compared. In both years, the variety Jolge was the susccptible check, Torbat, Pars and SBSI004 were the domestic resistant checks and Isella and Dorotea were the foreign resistant checks. According to severity of infection, it was found that in both years, the severity of infection was higher in Zarghan than Mashhad and Miandoab. The results also showed that the quality of sugar beet is more influenced by locationwhile the number of roots and root yieldare more influenced by Rhizomania infection. According to the results of the first year, the hybrids ((7112*KWs) * SB28) and ((7112* KWS)* SB26)were selected as superior hybrids due to high number of roots, root yield and sugar yield and also low sodium and indices of Rhizomania.These two genotypes had uniform plants with high percentage of green, relatively large vertical leaves in the early growing season. In the second year of experiment andin the absence of two mentioned hybrids, none of the other breedinggenotypes were selectable compared to the foreign control varieties were selectable. Although sugar yield in all circumstances was not related to severity of disease indices, but by using the equation presented in this studywith R2 = 0.35, sugar yield can be estimated by assessing root indices.