Luteoforol accumulates in Pr1; P1 cob glumes. (A) Ear phenotypes showing cob glumes pigmentation. Cob glumes of pr1 are light red while Pr1 has dark red cob glumes in the presence of P1-wr or P1-rr alleles. Pr1 and pr1 ears carrying p-del2 do not show any pigmentation. (B) Absorption spectra of cob glume extracts. Methanolic extracts from cob glumes of Pr1 ears in genetic background of P1-wr and P1-rr alleles gave maximum absorption at 498 nm. Cob glumes from pr1 ears in P1-wr and P1-rr genetic background gave maximum absorption at 482 nm. These spectra at 498 and 482 correspond to peaks for standard luteolinidin and apigeninidin, respectively (see inset). No absorption peak for flavan 4-ols was observed in p-del2 cob glumes.