A+b

Genes A and b

Anthocyanins are regulated in peas by a number of genes. Some of these genes control the distribution of the pigmentation, like 'P ' and 'Pur ' for purple pods, or the 'd' alleles which control pigmentation in leaf axils, while others regulate the chemestry of the anthocyanin, itself. The 'a' gene (acyanogenic) regulates the complete presence or absence of anthocyanin in the plant. The 'A' allele is completely dominant, and conditions the presence of anthocyanins in various plant parts, such as the flower and the axil (above center). The'a'allele conditions the lack of anthocyanin in the plant (above left). The 'b' gene regulates the hydroxylation of the B-ring of the anthocyanin molecule. The recessive 'b' allele lightens the deep red pigments of 'A' to an orange-pink color (above right). The effect of b is pleiotropic on axil and seed coat colors.

The A gene maps near the middle of linkage group IA, and information for the genotype at the A locus is recorded for 431 accessions in this collection. If you would like to query for the A locus, click here.

The B gene maps toward the end of linkage group III, and information for the genotype at the B locus is recorded for 199 accessions in this collection. If you would like to query for the B locus, click here.