Location: Sugarbeet and Potato Research2018 Annual Report
Objective 1: Identify genes and metabolic pathways responsible for deterioration of sugar beet root quality in storage, and develop new and more efficient storage protocols for wounded and drought-stressed sugar beet roots. Objective 2: Develop and release superior sugar beet germplasm with improved genetic diversity, resistance to the sugar beet root maggot, and improved processing quality. Objective 3: Develop physiological methods that promote and enhance natural plant defense mechanisms of sugar beet, including manipulation by plant hormones. Objective 4: Develop genomic and transcriptomic resources to better identify fungicide-resistant and fungicide-sensitive strains of Cercospora beticola. Objective 5: Facilitate the development of improved sugarbeet disease resistance to C. beticola through comparative genomics, transcriptomics, and pathogenicity studies on strains isolated from wild sea beet and cultivated sugarbeet germplasm. Objective 6: Develop improved sugarbeet resistance to C. beticola using effector-based screening.
The sugarbeet industry is a significant contributor to the U.S. economy and ensures a domestic supply for a staple in the American diet. The industry’s future, however, is challenged by stagnant sugar prices, increasing production costs, and competition from alternative sweeteners, sugarcane and imported sugar. Increased productivity is essential for the industry to remain profitable, competitive and sustainable. Sugarbeet productivity is determined by the quantity of sugar produced after processing. This yield, the extractable sugar yield, depends on sucrose accumulation during production, sucrose retention during storage, and sucrose recovery during processing. Physiological and genetic research is proposed that potentially will lead to new production and storage protocols and new hybrids to improve sucrose accumulation, retention, and recovery during production, storage, and processing. Specifically, the proposed research will (1) increase production yield by (a) generating genetically diverse germplasm with unique disease, pest, and stress resistance genes, (b) creating improved breeding lines with resistance to the sugarbeet root maggot, and (c) utilizing plant hormones to induce native plant defense mechanisms to enhance yield; (2) reduce storage losses by (a) identifying genetic and metabolic pathways responsible for sucrose and quality losses during storage, (b) characterizing temperature effects on postharvest wound-healing, (c) determining preharvest drought effects on storage properties, and (d) evaluating the effects of defense-inducing plant hormones on storage properties; and (3) improve sucrose recovery by creating germplasm lines with reduced concentrations of compounds that prevent the extraction of a portion of the sucrose during processing.
Project was initiated April of 2018 and replaces Project 3060-21000-040-00D, “Physiological and Genetic Approaches to Improving Extractable Sugar Yield in Sugarbeet”. Project 3060-22000-049-00D, “Improved Cercospora Leaf Spot Management for Sugarbeet Using Molecular Technologies”, was merged with this project June of 2018. Research toward all research objectives began in FY2018. Under Objective 1, sugarbeet roots with varying degrees of postharvest deterioration were evaluated for changes in storage respiration rate and root firmness. RNA was also isolated and sequenced from these roots and an analysis of changes in gene expression in relation to postharvest deterioration was begun. Research to determine the effects of storage temperature on sugarbeet root wound healing processes was also initiated and determination of relationships between storage temperature, wound healing and water loss in storage are complete. Under Objective 2, populations derived from wild by cultivated crosses are in the field and selection for improved sucrose concentration will begin after harvest. Plants for a second cycle of divergent selection for loss-to-molasses, a measure of the sucrose not normally extracted in normal factory operations, are in the field; selection will be based upon laboratory analysis after harvest. Selection for increased sucrose in sugarbeet root maggot resistant breeding populations will begin when plants now in the field are harvested. Under Objective 3, a field study to determine the effects of methyl jasmonate (MeJA) and salicylic acid (SA) applications on sugarbeet root yield, sucrose content, and sucrose yield was started. MeJA and SA effects will be evaluated after roots are harvested in the fall.