Studies on the flower colours in Rosa, with special references to the biochemical and genetic analyses and to the application of those results to the practical breeding. Ⅲ

1. The anthocyanins in flowers of garden rose ”Frensham” were isolated and identified by paper chromatographic methods. The anthocyanins identified were cyanin, pelargonin, chrysanthemin, and p-coumaroyl cyanin which was assumed to be cyanidin 3 -p-coumaroylglucoside 5 -glucoside. 2. Chrysanthemin of ordinary garden roses appear after anthesis and increase with flower age. But chrysanthemin of ”Frensham” was unusual in synthesizing mechanism. It occured before anthesis and practically did not fluctuate with flower age. 3. Replacement of the ordinary 3 : 5-diglucosides with the 3-glucosides of ”Frensham” type, e.g. cyanin with chrysanthemin was considered to afford more brilliant flower colours. And also the unfading anthocyanin colours might be realized from the coupling of two enzymatic systems, one concerning with the formation of the 3-glucosides of ”Frensham” type and the other of the light induced 3-glucosides of ordinary garden roses. 4. In stock, Matthiola incana, the shift towards the bluer shade appeared to originate from the acylation of anthocyanin molecule. If this situation is true, the p-coumaroyl cyanin might offer the third clue to so-called blue roses.