Ethiology of SugarBeet Bacterial Blight and Necrosis, Disease Incidence, Disease Severity and Cultivar Susceptibility
2013
Ghasemi, A., Iranian Research Institute Of Plant Protection | Lak, M.R. | Zohor Paralak, E. | Samavatian, H.
During the years of 2010-2012 sugar beet growing regions of Markazi, Kermanshah, Khorasan, Isfahan and West Azarbayejan multiple visits were preformed. Blighted beet leaves from different areas were sent to the Plant Protection Research Institute and the bacterial pathogen es were isolated. Under field conditions randomly visited 100 plants per farm and percent of leaf blight were evaluated and the results were adjusted separation by laboratory results. Disease incidence of farms in different provinces ranged from zero to 40 percent. According to phenotypic characteristics and pathogenicity of 42 isolates of sugar beet leaves identified as Pseudomonas syringae pv. aptata and 12 othere isolates was as a Pantoea ananatis. Pseudomonas strains are genetically homogenous and there was no significant difference between them. The Pseudomonas strains have 97% similarities to Ps. pv. syringae by sequencing of 16SrDNA. Yellowish isolates were identified by sequencing the RNA polymerase beta subunit gene and 100 percent owned by its similarity to Pantoea ananatis confirmed. The results showed that Xanthomonas sp. was not found in all investigated area that the beet leaf blight has been observed. In order to assess the disease severity crop losses by bacterial blight of sugar beets varieties, sugar beet seed comprises nine genotypes 20583, 20673, 20606, 20542, 20347, 20683, 20650, 20591, and 20397 received from Sugar Beet Seed Institute in three replications were planted in a randomized complete block design. The results showed that all tested genotypes are susceptible to bacterial blight. The effect of bacterial leaf blight on reduction of sugar beet yield, sugar content, sugar yield and net sugar yield were 27, 8, 33 and 32 percent, respectively.
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