Genetic Modification of Hydroxylation Pattern in Radish Anthocyanins

Studies on Anthocyanins, XLII

Abstract

This paper deals with the genetic factors controlling the root colors in radish, that have appeared in the cross between the red and white varieties.
The pigment in the red variety is the raphanusin (triglucoside of pelargonidin), which is acylated with cinnamic acid derivatives.
The F₁ plants were all purple in root color. The purple pigment was shown paper-chromatographically to be composed solely of cyanidin glycoside, structure of which just corresponds to that of the pigment in the red parent.
In the following F₂ generation, segregation occurred into three classes, purple (cyanidin glucoside), red (pelargonidin glucoside), and white (no pigment), in a ratio of 9:3:4, respectively.
The genetic analyses as such indicate the participation of two pairs of conditional alleles, for which R and E are presumed by the present authors. A factor R contributes to the production of pelargonidin glycoside, and another factor E to the formation of a hydroxylation enzyme which is effective for the production of the purple pigment (cyanidin glycoside).
If we assume the genotype of both parents as RRee for the red and rrEE for the white, the F₁ and F₂ results may be explained with reasonable certainty.