Physiological and genetic approaches to improving extractable sugar yield in sugarbeet
Sugarbeet and Potato Research
Project Number: 5442-21000-040-00
Start Date: Oct 01, 2013
End Date: Sep 30, 2018
Objective 1: Identify physiological approaches for reducing sucrose loss due to storage rot and environmental stresses, including cold, drought, and soil salinity, using plant inducible defenses.
Subobjective 1a: Determine the ability of jasmonic acid (JA) and salicylic acid (SA) to reduce the incidence and severity of storage rot due to Botrytis cinerea, Fusarium graminearum, Penicillium claviforme, and Phoma betae.
Subobjective 1b: Determine the ability of jasmonic acid and salicylic acid to mitigate the impact of environmental stress caused by limited water availability, cold temperature, or high soil salinity.
Subobjective 1c: Identify JA- and SA-induced biochemical and molecular changes associated with the induction of native defense responses by characterizing enzymes and gene products implicated in inducible defense responses via global transcriptional analysis.
Objective 2: Identify the physiological mechanisms that regulate sugarbeet root respiration and resultant sucrose loss, and characterize the impact of Rhizoctonia root rot and leaf regrowth on sucrose loss during root storage in order to optimize storage management practices.
Subobjective 2a: Identify enzymatic reactions and metabolic intermediates in sucrose catabolic pathways that may restrict root respiration rate.
Subobjective 2b: Determine the effects of Rhizoctonia root and crown rot on root storage properties in relation to disease severity and duration of storage.
Subobjective 2c: Determine the effect of postharvest leaf regrowth on sugarbeet root respiration and the effect of storage temperature on leaf regrowth.
Objective 3: Characterize the root impurity components that interfere with sucrose extraction during processing, and develop germplasm with reduced concentrations of these compounds.
Objective 4: Enhance the genetic diversity of breeding gene pools and breed genetically diverse sugarbeet lines with improved sugarbeet root maggot resistance.
Subobjective 4a: Enhance the genetic diversity of breeding gene pools through introgression of exotic germplasm.
Subobjective 4b: Through traditional breeding approaches, develop improved sugarbeet root maggot resistant germplasm.
The U.S. sugarbeet industry produces 60% of domestically grown sugar and nearly half of domestically consumed sugar. Thirty-two million tons of sugarbeet roots, valued at 2.1 billion dollars, are produced annually. The sugarbeet industry faces intense competition from alternative sweeteners and escalating production costs. For the industry to remain viable and to ensure a reliable, domestic supply of a staple in the American diet, increases in net productivity are essential. The yield of sugar produced after processing, or the extractable sucrose yield, determines net productivity for the sugarbeet crop. This yield depends on biomass and sucrose accumulation during production, sucrose retention during postharvest storage, and sucrose recovery during processing. The goal of research proposed in this project is to increase sugarbeet extractable sucrose yield by generating information and genetic resources that will lead to new production and storage protocols and improved hybrids for enhanced sucrose yield at harvest, improved sucrose retention during storage, and increased sucrose recovery during processing. Specific goals are to (1) determine the potential of inducible defense responses to reduce yield losses due to environmental stresses and storage rots, (2) determine the endogenous mechanisms that regulate root respiration during storage, (3) characterize the impact of Rhizoctonia root and crown rot and leaf regrowth on postharvest losses, (4) develop germplasm that facilitates improvements in processing quality, (5) develop germplasm that broadens the genetic base of sugarbeet, and (6) develop germplasm that combines high levels of sugarbeet root maggot resistance with resistance to prevalent diseases and improved sucrose concentration.