Location: Northwest Irrigation and Soils Research2008 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. Formerly 5368-21220-002-00D (5/08).
3. Progress Report
Objective 1. The work to develop expressed sequenced tags-simple sequence repeats (EST-SSR) and single nucleotide polymorphic (SNP) markers combined with association mapping and markers linked to curly top and rhizomania resistance is proceeding as expected. Parental lines were selected after three selection cycles in the field and in the green house for developing double haploid mapping populations. This research relates to National Program 301 Component II-Crop Informatics, Genomics, and Genetic Analyses, Problem Statement IIc-Genetic Analyses and Mapping of Important Traits. Objective 2. Work to screen germplasm for novel sources of resistance to curly top was promising. Plant introductions (PI) highly resistant to curly top were identified and breeding populations are under development, which started with producing selfed (S1) generations. Additional research is in progress based on these initial screenings. The survey of curly top species in the Western U.S. has been completed and submitted for publication. This research relates to National Program 301 Component III-Genetic Improvement of Crops, Problem Statements IIIa-Genetic Theory and Methods of Crop Improvement, IIIb-Capitalizing on Untapped Genetic Diversity, and IIIc-Genetic Enhancement/Release of Improved Genetic Resources and Varieties and National Program 303 Component III-Plant Disease Resistance, Problem Statement IIIb-Disease Resistance in New Germplasm and Varieties. Objective 3. The surveys for both fungal and bacterial root rot have been completed. The bacterial portion of the survey was recently published, and a publication for the fungal portion of the project is being prepared. Isolates for the Rhizoctonia project have been collected, pathogenicity tests on sugarbeet have been completed, and DNA has been isolated. The genetic diversity work remains to be completed. The development of a Leuconostoc assay is proceeding as expected. This research relates to National Program 303 Component II-Biology, Ecology, Epidemiology, and Spread of Plant Pathogens and Their Relationships with Hosts and Vectors, Problem Statement IIb-Plant-Microbe-Vector Interactions. Objective 4. The second year of storage work for the rhizomania and curly top research was successfully completed and published. The work to develop a cultivar selection assay for storability has been started. We also initiated studies to look at the influence of Leuconostoc on the storability of sugarbeet. This research relates to National Program 303 Component IV-Biological and Cultural Strategies for Sustainable Disease Management, Problem Statement IVb-Pathogen, Plant, and Antagonist Interactions. Objective 5. The studies with manure and Rhizoctonia and insecticide seed treatments have been initiated. This research relates to National Program 303 Component IV-Biological and Cultural Strategies for Sustainable Disease Management, Problem Statement IVc-Application of Sustainable Disease Management Tools.
1. DNA Markers Associated with Beet Curly Top Disease Resistance Identified. Curly top is a disease in sugar beet that decreases crop productivity. DNA markers associated with beet curly top are needed to develop resistant variations. Association mapping was used by ARS scientists in the Northwest Irrigation and Soils Research Unit in Kimberly, ID to identify markers associated to disease resistant genes in a population of 170 individuals of elite germplasm, pre-commercial, and commercial varieties. This population has been genotyped with single nucleotide polymorphic (SNPs) markers distributed genome-wide and simple sequence repeats (SSRs). The population was found to be suitable for association mapping, and associated markers have been identified. These markers will allow curly top resistance to be incorporated into cultivars via marker assisted selection. Accomplishment addresses National Program 301 Component II-Crop Informatics, Genomics, and Genetic Analyses, Problem Statement IIc-Genetic Analyses and Mapping of Important Traits.
Strausbaugh, C.A., Eujayl, I.A., Rearick, E., Foote, P. 2008. Transgenic sugar beet cultivars evaluated for resistance to rhizomania and storability in Idaho, 2007. Plant Disease Management Reports. 2:FC106.