Plant Regeneration from Tissue Cultures of Maize¹

Abstract

Abstract Effective utilization of cell and tissue culture methods in Zea mays research requires cultures capable of plant regeneration. These differentiated plants would provide a direct link with conventional genetic and breeding procedures. Maize callus from embryo scutellar tissues was initiated and maintained on MS medium inorganic components, Straus medium vitamins and amino acids, 20 g sucrose and 8 g agar per liter, and 2 mg 2,4‐dichlorophenoxyacetic acid (2,4‐D)/liter. Callus has been maintained subculture every 21 to 28 days and has remained capable of differentiation for 9 months. Regeneration of complete plants was accomplished by subculture of callus to 0.25 mg 2,4‐D/liter for 30 days followed by transfer to 2,4‐D‐free culture medium. At 0.25 mg 2,4‐D/liter numerous curled and wrinkled leaves developed. Approximately 200 complete plants have been differentiated. after transfer to the 2,4‐D‐free medium. Root tip cells from five plants indicated that each had 20 chromosomes. After transplantation to soil, 10 to 15% of the plants survived and grew normally. The optimum embryo age for scutellar callus initiation was 18 days post‐pollination. Hormone combinations such as 1 mg 2,4‐D, 4 mg a‐naphthaleneacetic acid (NAA), and 0.05 mg 6‐(γ,γ‐dimethyl allylamino)‐purine (2iP)/liter may increase the efficiency of scutellar callus initiation.