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Evaluation of commercial sugar beet hybrids for resistance to curly top in Malheur County, OR, 2005

Strausbaugh, C.A. and Gillen, A.M. (2006) Evaluation of commercial sugar beet hybrids for resistance to curly top in Malheur County, OR, 2005. Biological and Cultural Tests for Control of Plant Diseases. 21:p. FC039.

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Commercial sugar beet hybrids were evaluated for resistance to Beet severe curly top virus in a furrow-irrigated sugar
beet field near Ontario, OR where curly top had been a problem in previous years. The field trial relied on natural infection
and was planted on 6 Apr. Plots were planted to a density of 285,120 seeds/A, and thinned to 40,731 plants/A. Plots were
four rows wide (22 in. between rows) and 23 ft long. The experimental design was a randomized complete block with eight
replications. The crop was managed according to standard cultural practices. The weather during the growing season was
normal except for above average temperatures in Mar and Aug and above average precipitation in Apr and May. Disease
pressure was uniform and moderately severe. Disease data were recorded on 16 Sep by three individual raters separately
using a disease index of 0 to 9 (0 = no symptoms; 9 = dead plant). The three ratings per plot were averaged prior to analysis.
The center two rows were harvested on 13 and 14 Oct using a small plot harvester. Yield data were reduced by 10% to
account for tare. Sugar content of the beets was determined by the Amalgamated Sugar Co. laboratory using a polarimeter,
and recoverable sugar was estimated based on percent sugar and conductivity. Data were analyzed using the general linear
models procedure (Proc GLM-SAS), and Fisher's protected LSD was used for mean comparisons.
Yields were typical for this site and above average for growers. The commercial hybrids response to Beet severe curly top
virus ranged from acceptable (slight leaf curl = 2 to most leaves with moderate curling = 4) to severe (most larger leaves
becoming prostrate = 6). Analysis of variance indicated there were significant differences among hybrids for disease index,
root yield, sugar content, and estimated recoverable sugar. Based on Spearman's coefficient of rank correlation, our disease
ratings positively correlated (r s = 0.82, P < 0.0001) with those from the 2005 Curly Top Nursery in Kimberly, ID. There was
an inverse relationship (rs = -0.63, P = 0.0005) between estimated recoverable sugar and disease index.

Item Type: Article
NWISRL Publication Number: 1194
Subjects: Irrigated crops > Sugarbeet > Resistance
Irrigated crops > Sugarbeet > Curly top
Depositing User: Users 3 not found.
Date Deposited: 24 Mar 2008 21:29
Last Modified: 24 Oct 2016 15:50
Item ID: 1222