Location: Northwest Irrigation and Soils Research2011 Annual Report
1a. Objectives (from AD-416)
Objective 1: Develop molecular genetic markers linked to sugarbeet chromosomal regions that confer improved resistance to pathogens. Objective 2: Develop agronomically-superior sugarbeet germplasm with resistance to Beet severe curly top virus (BSCTV). Objective 3: Determine the distribution and diversity of sugarbeet root rot organisms. Objective 4: Determine the effects of pathogens on sugarbeet post-harvest quality and storability. Objective 5: Develop innovative disease management options for BSCTV and root rot organisms.
1b. Approach (from AD-416)
Establish a sugarbeet research program in genetics and plant pathology using classical and molecular approaches to improve the sugarbeet genetics pool and disease management options, and enhance crop quality, productivity, yield, and profitability of production.
3. Progress Report
Objective 1: An F2 population, segregating curly top, was genotyped with DArT, EST-SSRs and SNP markers and phenotyped for beet curly top to identify DNA markers linked to beet curly top resistance. Advanced breeding lines and parental lines were genotyped with DArT, EST-SSRs and SNP. The mapping population has been advanced to F4 in an effort to develop recombinant inbred lines for field screening for quantitative traits of beet curly top disease. Objective 2: Tissue culture was used to develop doubled haploid lines (DHLs). These lines will serve in pre-breeding and inheritance studies of beet curly top and other diseases. Seeds were produced from three DHLs for greenhouse screening for beet curly top and other diseases. Advanced germplasm populations were produced using mass selection after three field screening cycles. Objective 3: Genetic diversity and pathogenicity data generated for Rhizoctonia solani isolates were published. A greenhouse assay for bacterial root rot caused by Leuconostoc was compared with both storage and field data. Verticillium dahliae isolates were determined to belong to vegetative compatibility group 4A, which is the same group that causes potato early dying, the most important yield limiting disease problem on potatoes in Idaho. Wilt caused by Verticillium dahliae is also the number one disease problem in mint. Vertcillium wilt is not recognized as an important yield limiting problem for sugarbeet, but susceptible sugarbeet may lead to inoculum buildup in fields and compromise yield in subsequent crops. Objective 4: Data on the influence of storing rotted sugarbeet roots with healthy roots was accepted for publication. A fungus not previously described was found to be associated with stored sugarbeet roots. An article establishing the existence of this fungus has been accepted for publication. Objective 5: Soil samples are being characterized via real-time polymerase chain reaction to establish the distribution of bacteria in soil both with and without manure. Seed treatment trials were conducted to test the efficacy of seed treatments and host resistance in controlling curly top and pests in sugarbeet.
1. Influence of root rots on sugarbeet storability. Root rot caused by Rhizoctonia solani and Leuconostoc mesenteroides can not only lead to yield loss in the field but this rot complex also causes sucrose loss in storage. When placed in storage, rotted roots caused neighboring healthy roots to have 7% more root surface discoloration, 14% more frozen root area, 5% more sucrose loss, and 8% less recoverable sucrose. These data generated by ARS researchers at Kimberly, Idaho, demonstrate the importance of directly processing rotted roots rather than storing them in piles to be processed at a later time. These data also emphasize the need for developing better disease management options for root rots in the field.
2. Curly top resistant sugar beet. The most economical method for controlling curly top disease in sugar beet is developing resistant varieties. ARS researchers at Kimberly, Idaho, identified a major trait linked to beet curly top resistance and developed double haploid lines. Release is planned in 2012 as the first pure parental lines for beet curly top resistance. These breeding lines will be used by commercial sugar beet seed companies to produce seed with enhanced resistance to curly top.
Strausbaugh, C.A., Eujayl, I.A., Foote, P. 2011. Seed treatments for the control of insects and diseases in sugarbeet. Journal of Sugarbeet Research. 47(3&4):105-125 (DOI: 1035274/jsbr.47.3.105).