Beet curly top resistance in USDA-ARS Kimberly sugar beet germplasm, 2013

Curly top caused by Beet curly top virus is a widespread disease problem vectored by the beet leafhopper in semiarid sugar beet production areas. Host resistance is the primary defense against this problem, but resistance in commercial cultivars is only low to intermediate. In order to identify novel sources of curly top resistance, 14 sugar beet lines were screened in a disease nursery in 2013. The lines were arranged in a randomized complete block design with six replications. A curly top epiphytotic was created by releasing six viruliferous beet leafhoppers per plant at the four- to six-leaf growth stage on 27 Jun. Foliar symptoms were evaluated on 16 Jul using a scale of 0-9 (0 = healthy and 9 = dead) in a continuous manner. Curly top symptom development was uniform and no other disease problems were evident in the plot area. The disease pressure in the test was moderately severe with good symptom development in the susceptible check. Based on all variables, three of the lines were not significantly different from the resistant control, HM PM90. These germplasm lines will be released to the general public, so they can be utilized to improve resistance in commercial cultivars

Identification of differentially expressed UniGenes in developing wheat seed using digital differential display

The wheat UniGene sets, derived from over one million Expressed Sequence Tags (ESTs) in the NCBI GenBank, offer a platform for identifying differentially expressed genes in wheat seeds. This report illustrates a means to efficiently utilize this public database for gene expression (transcriptome) profiling of developing wheat seed. Using a data mining tool known as Digital Differential Display (DDD), thirteen pair-wise comparisons were performed on seven seed cDNA libraries from five varieties at various seed development stages. DDD identified 46 seed-specific UniGene sets, excluding the well characterized ‘‘housekeeping’’ and seed storage protein genes. Additionally, seed- and developmentally-specific UniGenes were identified. Some of these genes encode for proteins such as purothionins, serpins, a-amylase inhibitors, lipid transfer proteins, and other unknown but novel gene sequences. Specifically, the wheat serpin and b-purothionin precursor were found to be expressed at higher levels in hard varieties than soft varieties. This study supports the starting premise that by implementing in-silico analysis of the wheat UniGene database, it is possible to rapidly create transcriptional profiles of known and novel genes in developing seeds

Rhizoctonia root rot resistance in commercial sugar beet cultivars in Twin Falls County, ID, 2012

Rhizoctonia root rot continues to be a concerning problem in sugar beet production areas. To investigate resistance to this disease in 26 experimental sugar beet cultivars, field studies were conducted with three Rhizoctonia solani AG-2-2 IIIB strains. Based on means for the 26 cultivars, surface rot ranged from 0 to 93% depending on the strain-cultivar combination. Both the number of dead plants and root surface area rotted resulted in significant (P < 0.0004) cultivar differences. Based on Spearman’s rank correlation coefficient, there was always a significant relationship (P < 0.0279) when comparing cultivar performance across all three strains regardless of disease variable. The three most resistant cultivars performed well against all strains and variables, but still had half the root surface area rotted. Additional efforts need to be made to get more resistance to this disease problem in commercial sugar beet cultivars

Beet curly top resistance in USDA-ARS Kimberly germplasm lines evaluated in Idaho, 2017

Curly top caused by Beet curly top virus is a widespread disease problem vectored by the beet leafhopper in semiarid sugar beet production areas. Host resistance is the primary defense against this problem, but resistance in commercial cultivars is only low to intermediate. In order to identify novel sources of curly top resistance, 13 sugar beet lines were screened in a disease nursery in 2017. The lines were arranged in a randomized complete block design with six replications. A curly top epiphytotic was created by releasing six viruliferous beet leafhoppers per plant at the four- to six-leaf growth stage on 14 Jun. Foliar symptoms were evaluated on 6 Jul using a scale of 0-9 (0 = healthy and 9 = dead) in a continuous manner. Curly top symptom development was uniform and no other disease problems were evident in the plot area. The checks performed as expected for both the visual rating and ELISA. Based on both visual ratings and ELISA, KDH4-9 (PI683513) and KDH13 (PI663862) performed the same as the resistant check. All the KDH13 progenies (crossed to susceptible parental lines) had moderate visual ratings, while two of the progenies (KDH13/EMS9 and KDH13/19-19) had ELISA values that were not different from the resistant check. KDHEMS09 is new line that had very low virus accumulation. These results and germplasm information will be accessible through the USDA-ARS, NPGS GRIN database (http://www.ars-grin.gov/npgs/index.html). These germplasm lines will be released to the general public, so they can be utilized to improve curly top resistance in commercial sugar beet cultivars

Influence of Sugarbeet Tillage Systems on the Rhizoctonia-Bacterial Root Rot Complex

The Rhizoctonia-bacterial root rot complex in sugarbeet caused by Rhizoctonia solani and Leuconostoc mesenteroides can cause significant yield losses. To investigate the impact of different tillage systems on this complex, field studies were conducted from 2009 to 2011. Split blocks with conventional and strip tillage as main plot treatments were arranged in a randomized complete block design with four replications. Within main plots, there were seven treatments (non-inoculated check and six R. solani AG-2-2 IIIB strains). Regardless of tillage, the roots responded in a similar manner for fungal rot (conventional 8% versus strip 7%), bacterial rot (26% versus 34%), total rot (33% versus 41%), neighboring roots infected (1.7 roots versus 1.5 roots), distance spread (157 mm versus 150 mm), and the number of dead plants (12% versus 14%). Most R. solani strains also responded in a similar manner for disease variables. Strip tillage resulted in 6% more root yield in 2009 (P = 0.087), while conventional tillage resulted in 7% and 27% more root yield in 2010 (P = 0.063) and 2011 (P = 0.012), respectively. The tillage systems influenced disease variables in a similar manner, but more studies will be needed to determine their impact on yield

Rhizoctonia root rot resistance in experimental sugar beet cultivars in Twin Falls County, ID, 2012

Rhizoctonia root rot continues to be a concerning problem in sugar beet production areas. To investigate resistance to this disease in 26 experimental sugar beet cultivars, field studies were conducted with three Rhizoctonia solani AG-2-2 IIIB strains. Based on means for the 26 cultivars, surface rot ranged from 0 to 93% depending on the strain-cultivar combination. Both the number of dead plants and root surface area rotted resulted in significant (P < 0.0004) cultivar differences. Based on Spearman’s rank correlation coefficient, there was always a significant relationship (P < 0.0279) when comparing cultivar performance across all three strains regardless of disease variable. The three most resistant cultivars performed well against all strains and variables, but still had half the root surface area rotted. Additional efforts need to be made to get more resistance to this disease problem in commercial sugar beet cultivars

Beet curly top resistance in USDA-ARS Kimberly germplasm, 2019

Curly top caused by Beet curly top virus (BCTV) is a widespread disease problem vectored by the beet leafhopper in semiarid sugar beet production areas. Host resistance is the primary defense against this problem, but resistance in commercial cultivars is only low to intermediate. In order to identify novel sources of curly top resistance, 8 sugar beet lines produced by the USDA-ARS Kimberly sugar beet program were screened in a disease nursery in 2019. The lines were arranged in a randomized complete block design with six replications. A curly top epiphytotic was created by releasing six viruliferous beet leafhoppers per plant at the four- to six-leaf growth stage on 3 Jul. Foliar symptoms were evaluated on 22 July using a scale of 0-9 (0 = healthy and 9 = dead) in a continuous manner. Curly top symptom development was uniform and no other disease problems were evident in the plot area. The disease pressure in the test was moderately severe with good symptom development in the susceptible checks. Based on the visual rating, four entries (segregating populations) and two genetic stock line entries were not significantly different from the resistant checks. The resistant segregating populations will be suitable for single trait selection and advancement to breeding lines to enrich the BCTV resistance gene pool in the USDA-ARS sugar beet germplasm

Influence of sugarbeet tillage systems on rhizoctonia-bacterial root rot complex

The Rhizoctonia-bacterial root rot complex on sugarbeet caused by Rhizoctonia solani and Leuconostoc mesenteroides can cause significant yield losses. To investigate the impact of different tillage systems on this complex, field studies were conducted from 2009 to 2011. Split blocks with conventional and strip tillage as main plot treatments were arranged in a randomized complete block design with four replications. Within main plots, there were seven treatments (non-inoculated check and six R. solani AG 2-2 IIIB strains). Regardless of tillage, the roots responded in a similar manner for fungal rot (conventional 8% versus strip 7%), bacterial rot (26% versus 34%), total rot (33% versus 41%), neighboring roots infected (1.7 roots versus 1.5 roots), distance spread (157 mm versus 150 mm), and the number of dead plants (12% versus 14%). Strip tillage resulted in 6% more root yield in 2009 (P = 0.087), while conventional tillage resulted in 7% and 27% more root yield in 2010 (P = 0.063) and 2011 (P = 0.012), respectively. The tillage systems influenced disease variables in a similar manner but more studies will be needed to determine their impact on yield. Control for the rot complex should focus on typical Rhizoctonia root rot control measures (crop rotation, in-furrow fungicide applications, irrigation management, and host resistance) while a better understanding of the complex continues to be developed

Rhizoctonia root rot resistance in commercial sugar beet cultivars in Twin Falls County, ID, 2012

Rhizoctonia root rot continues to be a concerning problem in sugar beet production areas. To investigate resistance to this disease in 26 commercial sugar beet cultivars, field studies were conducted with three Rhizoctonia solani AG-2-2 IIIB strains. Based on means for the 26 cultivars, surface rot ranged from 0 to 96% depending on the strain-cultivar combination. Both the number of dead plants and root surface area rotted resulted in significant (P < 0.0002) cultivar differences. Based on Spearman’s rank correlation coefficient, there was always a significant relationship (P < 0.0390) when comparing cultivar performance across all three strains regardless of disease variable. The three most resistant cultivars performed well against all strains and variables, but still had half the root surface area rotted. Additional efforts need to be made to get more resistance to this disease problem in commercial sugar beet cultivars

Rhizoctonia and Bacterial Root Rot in Sugarbeet

The Amalgamated Sugar Company production area in southern Idaho and southeastern Oregon suffers considerable losses from root rot in the field. Both Rhizoctonia and bacterial root rots on sugarbeet are common in Treasure Valley and Magic Valley (Fig. 1 and 2), while eastern Idaho fields seem to be relatively root rot free. The yield losses in some Treasure Valley fields can approach or surpass 50%. The growers not only suffer losses in the field, but diseased roots also store and process poorly, leading to additional losses