Genetic and Chemical Analysis of Deep Purple Flower in Soybean

A soybean [Glycine max (L.) Merr.] mutant line producing deep purple flowers (E013-C-1) was developed from an ethylmethane sulfonate-treated population of the cultivar 'Bay', which has purple flowers. Genetic analysis was performed on a cross between 'E013-C-1' and the cultivar 'Clark' that had purple flowers. F-1 plants had purple flowers whereas F-2 plants segregated into a 3: 1 purple/deep purple ratio. The results suggest that a single gene controls flower color and that purple color is dominant to deep purple. F-3 plants derived from F-2 plants with deep purple flowers were fixed for deep purple flowers. F-3 plants derived from F-2 plants with purple flowers segregated into two families segregating for flower color and one family that was fixed for purple flower color. The results confirmed that a single gene controls flower color and its recessive allele is responsible for deep purple flower color. The gene was designated Wd. Linkage mapping with simple sequence repeat (SSR) markers suggested that the Wd gene was located between Satt612 and Sct_199 in chromosome 18. Deep purple petals contained 50% higher levels of anthocyanins than purple petals. The vacuolar pH of deep purple flowers was similar to that of purple ones. These results suggest that the Wd gene controls the amount of anthocyanins and it is responsible for the development of deep purple flowers.