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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Soil Management and Sugarbeet Research » Research » Publications at this Location » Publication #384805

Research Project: Development of Sugar Beet Germplasm Enhanced for Resistance to Important and Emerging Plant Pathogens

Location: Soil Management and Sugarbeet Research

Title: Ft. Collins sugar beet germplasm evaluated for rhizomania and storage rot resistance in Idaho, 2020

Author
item Dorn, Kevin
item Strausbaugh, Carl

Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: Thirty sugar beet lines from the USDA-ARS Ft. Collins sugar beet program and five check cultivars were screened for resistance to Beet necrotic yellow vein virus (rhizomania) and to storage rot at the USDA-ARS North Farm in Kimberly, ID using a naturally infected field. The plots were rated for rhizomania foliar symptom (percentage of plants with yellow, stunted, upright leaves) development. At harvest, ten roots per plot were rated for rhizomania symptom development using a scale of 0 to 9 (0 = healthy and 9 = dead), and eight roots per plot were also placed in a mesh-onion bag and kept in an indoor commercial storage facility. After 131 days in storage, the roots were evaluated for the percentage of root surface area covered by fungal growth or rot. Data were analyzed in SAS, and statistical tests were used to compare average disease ratings across the experiment. The susceptible check plots (Check 1 and Red beet) had 100% foliar symptoms and high root disease ratings. Resistant check 3 had 1% foliar symptoms and a low root rating which indicates that resistance based on two genes is holding up. Single gene resistance (Checks 2 and 4) had foliar ratings ranging from 8 to 13% indicating single gene resistance is not completely effective. Three entries (13, 19, and 25) had a level of rhizomania resistance similar to resistant check 3 based on both foliar and root ratings. A number of the entries had resistance to fungal rots in storage, but only entries 13 and 19 performed well for all three variables. Some entries may serve as a starting point for identifying additional sources of resistance to rhizomania and storage rots.

Technical Abstract: Thirty sugar beet (Beta vulgaris L.) lines from the USDA-ARS Ft. Collins sugar beet program and five check cultivars were screened for resistance to Beet necrotic yellow vein virus (BNYVV), the causal agent of rhizomania, and to storage rot. The rhizomania evaluation was conducted at the USDA-ARS North Farm in Kimberly, ID which has Portneuf silt loam soil and had been in barley in 2019. In the spring the field was plowed and fertilized (110 lb N and 120 lb P2O5/A) and roller harrowed on 27 Mar 20. The germplasm was planted (density of 51,840 seeds/A) on 20 Apr. The plots were one row 10-ft long with 22-in. between-row spacing and arranged in a randomized complete block design with 6 replicates. The crop was managed according to standard cultural practices for southern Idaho. The trial relied on endemic field inoculum for rhizomania and storage rot development. The plots were rated for rhizomania foliar symptom (percentage of plants with yellow, stunted, upright leaves) development on 24 Aug. The plants were mechanically topped and hand harvested on 13-14 Oct. At harvest, ten roots per plot were rated for rhizomania symptom development using a scale of 0 to 9 (0 = healthy and 9 = dead; Plant Disease 93:632-638), with disease index (DI) treated as a continuous variable. At harvest, eight roots per plot were also placed in a mesh-onion bag and kept in an indoor commercial storage facility (temperature set point 34°F) in Paul, ID on 15 Oct. On 22 Feb 21, after 131 days in storage, the roots were evaluated for the percentage of root surface area covered by fungal growth or rot. Data were analyzed in SAS (Ver. 9.4) using the general linear model (Proc GLM) procedure, and Fisher’s protected least significant difference (a = 0.05) was used for mean comparisons. The root ratings were rank transformed prior to analysis, but the non-transformed means have been presented in the table. Rhizomania symptom development was uniform and other disease problems were not evident in the plot area. The BNYVV susceptible check plots (Check 1 and Red beet) had 100% foliar symptoms and high root disease ratings. Resistant check 3 had 1% foliar symptoms and a low root rating which indicates that resistance based on two genes is holding up. Single gene resistance (Checks 2 and 4) had foliar ratings ranging from 8 to 13% indicating single gene resistance is not completely effective, but the root ratings were still good. Three entries (13, 19, and 25) had a level of BNYVV resistance similar to resistant check 3 based on both foliar and root ratings. A number of the entries had resistance to fungal rots in storage, but only entries 13 and 19 performed well for all three variables. Some entries may serve as a starting point for identifying additional sources of resistance to BNYVV and storage rots.