The inheritance of flower colour pigments I. the genusAntirrhinum

Abstract

1. The. pigments of varieties, hybrids and seven species ofAntirrhinum have, been studied by paper chromatography. 2. The presence of glycosides of cyanidin, pelargonidin, apigenin and luteolin, described by earlier workers, is confirmed by this method. In addition, glycosides of aureusidin, a benzalcomriaranone, have been found, together with an unidentified aglycone (pigment 4); a second unidentified pigment is only found inA. orontium. 3. WithinA. majus single genes affect (1) the ability to produce any pigment at all (Y) (2) the ability to produce anthocyanin (R) and (3) the type of anthocyanin (B). Homo-logues of these genes occur in the speciesA. molle, A. meonanthum, A. linkianum, andA. ramosissimum. 4. The geneB produces cyanidin, and this gene or one closely linked to it is necessary for the production of the unidentified pigment 4. In the absence ofB, pelargonidin is formed, accompanied by two glycosides of apigenin. A third apigenin glycoside is found in all genotypes exceptyy. A major gene,L, is probably necessary for the production of luteolin. 5. The geneI, which determines the quantity and distribution of the yellow pigment, aureusidin, shows reversal of dominance in different groups of interspecific hybrids. This reversal may be due to a gene complex which modifies the production of anthocyanin and anthoxanthin. 6. A tentative scheme of pigment synthesis is outlined. This is based on the assumption that the genes affect precursors of the pigments rather than the pigments themselves and that the final products are the result of interaction and competition between these precursors.