Evidence for Simple Genetic Control of Sugar Type in Carrot (Daucus carota L.)1

Reducing sugar (glucose and fructose) and sucrose are the major free sugars (total sugars) in the carrot root. Striking genetic variation exists for the reducing sugar/total sugar ratio (percentage of reducing sugar). Inbred carrot lines with high and low percentages of reducing sugar were used as parents in establishing various F 1 , F 2 , F 3 and backcross populations to study the inheritance of root sugars. It was determined that a single major gene regulates the reducing sugar to sucrose balance in carrot roots with dominance for high percentage of reducing sugar. We propose that this gene be designated Reducing sugar , symbolized Rs . This relationship is of interest since sugars in the carrot root are a major storage carbohydrate and a primary component of carrot flavor.