Location: Crop Improvement and Protection Research
2012 Annual Report
1. Promoting sugar beet research concerning the isolation of specific genes and the development of germplasm, which may be used effectively in breeding to develop hybrids and varieties that are resistant to various pathogens, regionally adapted, suitable for various cultural practices, superior in biochemical attributes, and storable with minimum deterioration.
2. Establishing technology whereby new genetic characters, inbred lines, or sugar beet germplasm established via ARS research may be brought into widespread use by breeders and growers promptly, efficiently and at less cost.
3. Promoting research to develop better disease management, through an increased understanding of sugar beet disease etiology and epidemiology and an elucidation of the biochemistry, physiology and genetics of the sugar beet-pathogen-biocontrol agent interaction.
4. Increasing the understanding of the biochemical genetic and physiological basis of the development of the sugar beet plant, the storage of the harvested root and the extraction of sucrose from the beet to be better able to maximize the efficiency in the processing of sugar beet to sucrose and other products.
5. Evaluating, characterizing, and utilizing available genetic resources (esp., in the USDA-ARS NPGS Beta PI germplasm collection) to determine the genetic diversity within sugar beet and pathogen populations, to better understand and manage important pathogens of sugar beet, and to produce enhanced germplasm more rapidly and more efficiently to meet the changing needs of seed companies and the growers they serve.
162 SSR molecular markers were screened on two sets of DNA. First, product was amplified in four individuals from each of two Bvm accessions (set 1-BVM Individuals) to identify markers polymorphic within or between individuals of each accession. 11 markers were selected and run on 93 Bvm individuals, two commercial varieties, and one negative control (dH2O) (set 2-BVM 96). 24 Bvm accessions from eight countries were represented. Fragment analysis of PCR products was conducted on an Applied Biosystems 3500 genetic analyzer on-site. Screening with additional markers is underway.
Continued progress was made on the sugar beet pre-breeding population and line improvement program. At Salinas locations, 3,432 plots comprising 412 lines, populations, Bvm accessions, and commercial varieties were evaluated for traits including stand count, reaction to rhizomania, (and powdery mildew and cercospora when naturally present), tons roots harvested per acre, and percent soluble solids (a measure of percent sucrose). In Brawley field trials 864 plots and 106 lines, populations, Bvm accessions, and commercial varieties were evaluated for stand count, canopy yellowing due to SBCN, cyst count per plot, and tons roots harvested per acre.
Studies are examining differences in protein expression between sugarbeet carrying the traditional Rz1 gene, and sugarbeet carrying a distinct resistance gene (Rz2), in which resistance remains effective. Knowledge will be useful to industry in prolonging the longevity of resistance genes, and development of new methods for resistance.
Research associated with the influence of tillage systems on Rhizoctonia root rot was completed, submitted for publication, and accepted for publication. The research indicates that management for root rot should be the same in both systems since disease variables were similar in both tillage systems. Field, greenhouse, and storage studies to investigate cultivar selection for Rhizoctonia root rot were completed and submitted for publication. Studies investigating the interaction between Rhizoctonia solani and Leuconostoc mesenteroides were conducted and data are currently being analyzed.