Anthocyanin inheritance and instability in purple basil (Ocimum basilicum L.)

The instability of the purple pigments (anthocyanins) in purple basil varieties (Ocimum basilicum L.) limits their use as ornamental plants and as a potential anthocyanin source. Several self-pollinated generations of all purple plants were unsuccessful in stabilizing anthocyanin expression. In this study we investigated the inheritance and stability patterns of leaf traits using the Purple Ruffles variety. The results from the complete diallele crosses indicated anthocyanin expression in vegetative tissue is controlled by two dominant genes and ruffled leaf texture is controlled by a single recessive gene. Genes controlling leaf margin and leaf base structures were tightly linked to leaf texture. Essential oil production and oil constituents in leaves did not change as a result of the reversion in color. Color stability in cuttings was affected by the environment and the location where cuttings were taken. An accumulation of secondary metabolites (apigenin, genistein, and kaempferol) in green-reverted sectors on purple leaves was detected using reverse-phase high-performance liquid chromatography (HPLC) analysis; this suggested a potential block in the anthocyanin pathway. We hypothesize the reversion mutation is occurring in an anthocyanin regulatory gene.