In Vitro Culture of Grain and Vegetable Amaranths (Amaranthus Spp.)

We have developed in vitro culture systems for both “grain” and “vegetable” species of the genus Amaranthus. Leaf discs and hypocotyl segments from 2‐ to 3‐wk‐old seedlings of A. hypochondriacus, A. cruentus, and A. tricolor were cultured in B5 and MS media supplemented with 2,4‐dichlorophenoxyacetic acid, α‐naphthaleneacetic acid, benzyladenine and zeatin in various combinations. Rapidly growing callus and abnormal roots formed on leaf discs of A. hypochondriacus and A. cruentus in the presence of 0.1‐1.0 mg/l 2,4‐D. At higher levels (1.0‐10.0 mg/l) of 2,4‐D, embryo‐like structures arose from the surface and veins of the leaf discs. Shoots formed on hypocotyl‐derived callus of both grain species in B5 medium + 0.1 mg/l NAA and 0.1‐1.0 mg/l zeatin. Lower ratios of zeatin/NAA stimulated root formation from hypocotyl segments. Viable mesophyll protoplasts were isolated from primary leaves of all three species, with an enzyme solution of 1% Cellulysin and 0.05% Pectolyase Y‐23, producing a yield of more than 106 protoplasts/g fresh weight.