Flavonoid composition of red sorghum genotypes

The effect of genotype on flavonoid composition was investigated in 13 sorghum varieties using HPLC-DAD. Sorghums with red/purple secondary plant colour had the highest levels of 3-deoxyanthocyanins (32–680 μg/g) with the black pericarp sorghums having the highest. Sorghums with red secondary plant colour had a high proportion of apigeninidin compounds (66–89%), which suggested that secondary plant colour affects 3-deoxyanthocyanin composition. Red pericarp sorghums with tan secondary plant colour had the highest levels of flavones (60–386 μg/g). Flavanones were also detected in all sorghums with a red pericarp (8–48 μg/g) and secondary plant colour did not affect their levels (p > 0.05). The elevated 3-deoxyanthocyanin levels in the black sorghums were due to their pericarp colour. Black sorghum panicles that were exposed to sunlight during their development had three times more 3-deoxyanthocyanins (617 μg/g) than those that were covered with a paper bag (212 μg/g). This study showed that flavonoid levels and composition were affected by sorghum genotype. This information will help sorghum breeders to produce sorghum genotypes with maximum levels of desired flavonoids.