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USDA-ARS sugar beet germplasm developed in Salinas, CA, evaluated for rhizomania resistance in Idaho

Gillen, A.M. and Strausbaugh, C.A. and Gallian, J. (2007) USDA-ARS sugar beet germplasm developed in Salinas, CA, evaluated for rhizomania resistance in Idaho. Plant Disease Management Reports. 1:p. FC053.

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Abstract

Thirty-one sugar beet germplasm breeding lines and releases produced by the USDA-ARS sugarbeet program at Salinas, CA, and one line from the USDA-ARS sugarbeet program at East Lansing, MI, were evaluated for resistance to rhizomania under south-central Idaho conditions at Twin Falls, ID. The field had been identified as having Beet necrotic yellow vein virus (BNYVV), which overcomes resistance conditioned by the Rzl gene. Single-row plots 10 ft long with 22-in. spacing were planted on 23 May 05. Plants were thinned to 4 to 6-in. spacing in mid-Jun. The materials were predominantly multigerm; they were hand thinned to single plants during the first week of Jul. The trial layout was a randomized complete block with eight replicates, however, the blocks were divided into 16 sub-blocks of six rows in which single-row plots of two entries and four control lines were randomized. The control lines were Beta443OR (Rzl gene), GO17R (Rz2 gene), Angelina (Rzl+Rz2 genes) and Beta6600 (no resistance to rhizomania). This allowed each entry plot to have its own control (Local Control). This was necessary given the uneven distribution in the field of resistance breaking strains of BNYVV. Naturally occurring Curly top virus infection was found throughout the field early in the season. Many plants of the rhizomania susceptible control were killed apparently by curly top and therefore this should be considered when evaluating the results. Plants were scored 19 Sep for curly top using a 0-9 scale with 0 showing no symptoms and 9 being dead. Plants were topped, roots lifted then scored on 12-13 Oct. Four teams evaluated the trial for rhizomania with each team rating two replicates. Each root was scored based on the traditional 0 to 6 scale which was converted to a 0 to 9 scale. The categories were 0, 1, 3, 5, 6, 7 and 9 with 0-3 being resistant, 5-7 susceptible and 9 was dead. The average disease severity was determined to create a disease index (DI) for each entry and control. A second index (DI2) was calculated for each entry-plot to evaluate the entry relative to the mean of the Rz2 and Rzl+Rz2 Local Controls (DI of entry/mean DI of the Rz2 and Rzl+Rz2 Local Controls). The percent healthy roots (categories 0-3 combined) and the percent of healthy roots relative to Rz2 and Rzl+Rz2 Local Controls were calculated (PR and PR2, respectively). The DI and DI2 were transformed with the inverse square root and analyzed using PROC MIXED - SAS with Dunnett's test (P = 0.05) option and PROC GLM – SAS with Fisher's protected LSD test (P = 0.05) option, respectively. PR and PR2 were analyzed with PROC GLM –SAS using Dunnett's test (P = 0.05) and Fisher's protected LSD (P = 0.05) test, respectively. The analysis of variance of DI2 showed that block effects were significant, therefore Spearman's partial correlation (PROC CORR Spearman partial - SAS) was used to analyze the relationship of D1, PR, DI2, PR2, and curly top. PROC CORR Spearman -SAS was used to analyze the relationship between DI and DI2.

Item Type: Article
NWISRL Publication Number: 1207
Subjects: Irrigated crops > Sugarbeet > Resistance
Irrigated crops > Sugarbeet > Rhizomania
Depositing User: Carl Strausbaugh
Date Deposited: 24 Mar 2008 21:33
Last Modified: 24 Oct 2016 15:47
Item ID: 1226
URI: https://eprints.nwisrl.ars.usda.gov/id/eprint/1226

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