In Vitro Culture Of Maize (Zea Mays L.) Inbred Line Sm5-4

Tissue culture of inbred line SM5-4 maize (Zea mays L.), maternal parent of Putra J- 58 (F1 hybrids) was established using maize zygotic embryo as explant. To obtain embryogenic callus from mature and immature zygotic embryos of inbred line SM5- 4, manipulations of media components such as carbon, nitrogen, proline, and casein hydrolysate, and culture conditions such as incubation temperature, light, were carried out. Immature embryos have the ability to form callus and embryogenic calli, which can result in plant regeneration. At tissue culture level, the study aims at establishing the best tissue culture system via somatic embryogenesis and to overcome plant regeneration problems by manipulating the sucrose concentration, hormone combination and concentration, culture age, the type of medium formulation used to grow callus, incubation temperature, light and media formulation. Sterilization technique of maize from mature and immature maize seeds of the inbred line SM5-4 was investigated. Mature seeds (50 days old) and immature seeds (14 days after pollination) were disinfected by washing in different concentrations of sodium hypochlorite (Clorox) for different duration. Disinfection in 50%(v/v) Clorox solution (2.27% sodium hypochlorite) for 20 minutes gave 90% of contaminationfree culture of mature seeds whereas 50%(v/v) Clorox solution (2.27% sodium hypochlorite) for 15 minutes gave 75% of contamination-free culture of immature seeds. Reduction in Clorox concentration of 20% (v/v) Clorox (1.05% sodium hypochlorite) for 20 minutes gave high percentage (67%) of contamination- free culture of immature seeds that remain viable. N6 basal medium was found to be the best medium in enhancing both callus induction and embryogenic calli formation. The highest callus induction frequency on N6 basal medium supplemented with 9 pM 2,4-D from immature zygotic embryos was 79.5%. Both plants growth regulators, 2,4-D, IAA and BAP, kinetin, were capable of switching on the inductio