Location: Northwest Irrigation and Soils Research2009 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. Populations of parental lines and progenies were advanced to the phase of seed increase. This new set of germplasm represents significant progress towards broadening the genetic base of sugarbeet (Beta spp). Also, new selected plant introductions from wild sugarbeet and accessions from other continents were advanced to the seed increase phase. A new set of DNA markers was developed using Diversity Array Technology Pty Ltd markers (DArT). These markers were utilized for genotyping the new Northwest Irrigation and Soils Research Laboratory germplasm, in addition to other USDA-ARS germplasm and commercial cultivars. Paired crosses were made between resistant and susceptible sugarbeet parents to study inheritance of curly top. To augment the conventional hybridization (crossing) processes, tissue culture technology was utilized to develop pure lines. New haploid pure lines were produced from curly top resistant and susceptible elite lines. Doubling of the chromosomes, by using chromosomal doubling chemicals, is under progress. These inbred lines will be used as parental lines for developing mapping populations to identify genes regulating curly top. These lines and other progenies under development were genotyped with available DNA markers. Objective 2. Germplasm screening for response to various important sugarbeet diseases is a continuous process to search for novel sources of genetic resistance. New plant introductions from cultivated sugarbeet and wild sugarbeet were screened in the curly top and rhizomania nurseries. The survey of the curly top species in the Western U.S. has been published. To support the genetics work, scientists have also been cooperating on a project to develop an enzyme-linked immune-sorbent assay (ELISA) that will quantify the amount of virus in the plant tissue. We are in the testing phase for this assay. Objective 3. The survey of the fungi associated with root rot in the Amalgamated Sugar Company production area in southern Idaho has been accepted for publication. The Rhizoctonia isolates have been sequenced and submitted for publication along with the pathogenicity data collected the previous year. The Verticillium isolates were collected for a second year and placed in storage for future research. The Leuconostoc root rot assay research was repeated and submitted for publication. Objective 4. The second year of determining storability of sugarbeet cultivars was completed, and data from the project were published. A preliminary study was conducted to identify the influence of roots with bacterial root rot on the storability of healthy roots in an outdoor pile. Objective 5. Rhizoctonia/manure studies were repeated and the pathogenicity portion of the data was published with the fungal survey data. The isolates for the microbiology portion of this project are currently being identified through sequencing, Biolog plates, and other laboratory tests. Two seed treatment trials were conducted to test the efficacy of seed treatments and host resistance in controlling curly top and pests in sugarbeet.
1. Sugarbeet Cultivar Selection to Reduce Sugar Loss During Storage. Controlling sucrose loss during sugarbeet storage has been an industry goal since the 1950s. Healthy sugarbeet roots will lose 8–17% of their sucrose after 100 days in storage, but roots compromised by disease problems, particularly rhizomania in the field, can lose up to 90%. To reduce storage losses and improve resistance to rhizomania, a cultivar selection program was established by scientists at the Northwest Irrigation and Soils Research Laboratory, Kimberly, Idaho, with the cooperation of the Amalgamated Sugar Company, Boise, Idaho. If this selection program can increase the recoverable sugar 1-5%, it will enhance the profits of sugarbeet processors by millions od dollars.
2. Developed New DNA Markers for Sugarbeet. Sugarbeet populations are complex and difficult to analyze using the established low to medium throughput DNA-markers systems such as microsatellites (simple sequence repeats–SSR). High-throughput genotyping is required to achieve efficient molecular genetic analysis. The DArT marker-system is the highest-throughput and most cost-effective system. Approximately 1,500 sugarbeet DArT markers were developed in a collaboration between scientists at the Northwest Irrigation and Soils Research Laboratory, Kimberly, Idaho, and the researchers in Canberra, Australia. These DArT markers provide a ready-to-use platform for identification of economically important sugarbeet genes.
3. Developed New Germplasm Using Tissue Culture. Developing inbred lines in sugarbeet requires four to five years using a conventional single seed descent approach. To produce inbred lines in significantly shorter time, a tissue culture approach was used. ARS scientists at the Northwest Irrigation and Soils Research Laboratory, Kimberly, Idaho, (NWISRL) contracted with a Watsonville, California company to produce tissue culture (unfertilized ovule culture) derived inbred lines under technical advice from NWISRL. Doubled haploid pure inbred lines (DHL) were developed from germplasm resistant to curly top. These lines are ready to be used in crossings and the study of curly top inheritance.
Eujayl, I.A., Morris, C.F. 2009. Identification of differentially expressed UniGenes in developing wheat seed using digital differential display. Journal of Cereal Science. 49:316-318.