ARS | Publication request: Genetic control of Fructan Accumulation in Onion

Submitted to: National Allium Research Conference
Publication Type: Abstract Only
Publication Acceptance Date: November 1, 2006
Publication Date: December 7, 2006
Citation: Havey, M.J., Raines, S., Henson, C.A., McCallum, J. Genetic control of Fructan Accumulation in Onion [Abstract]. National Allium Research Conference. Available: http://vic/tamu.edu/narc

Technical Abstract: Fructans are soluble carbohydrates composed of chains of fructose attached to a basal sucrose molecule. Fructans are a good source of soluble dietary fiber associated with lower rates of colorectal cancer, and act as a prebiotic selectively encouraging growth of beneficial bifidiobacteria and lactobacilli in the gastro-intestinal tract. In onion, higher fructan concentrations are correlated with greater soluble solids content, longer dormancy, and higher pungency. Regions on onion chromosomes 5 and 8 accounted for a significant portion of the phenotypic variation for fructans, soluble solids, and dry matter. The region on chromosome 8 may carry a single locus (Frc) that explains a majority of phenotypic variation for fructan content. The region on chromosome 5 showed no significant effects on soluble solids content and dry matter when the family means were adjusted for dry weights. This indicates that this region may affect relative water content of bulbs; the accumulation of high concentrations of fructans reduces water retention, concentrating the solids and organosulfur compounds responsible for pungency. We produced larger family sizes, evaluated progenies in the field for fructan contents, and are presently using a candidate gene approach to identify the factors affecting fructan accumulation.