Regenerability of Elite Tropical Maize (Zea mays L.) Inbred Lines Using Immature Embryo Explants.

Abstract

Five elite tropical maize inbred lines; CML395, CML4 43, CML442, MAS [MSR/312]-117-2-2-1-B-5-B) and CML216 as a control, were evaluated for their regen erability making use of calli derived from immature zygotic embryos. Murashige and Skoog basal salts supplemented with 1.0, 1.5, 2.0 and 2.5 mg/L 2,4- dichlorophenoxyacetic acid were used to induce call us. Callus induction frequency and formation of embryogenic callus varied significantly (p<0.01) de pending on genotype and level of 2,4-dichlorophenoxyacetic acid. Shoot regeneration effi ciency also differed significantly (p<0.01) depending on genotype. Significantly (p<0.05) higher callus induction and frequency of embryogenic callus were obtained at 1 mg/L 2,4-dichlorophenoxyacetic acid, indicating this as the optimal level for regenerating these inbred lines. CML395 and CML442 revealed significantly (p<0.05) higher callus induction and embryogenic callus frequency compared to CML443 and MAS [MSR/312]-117-2-2-1-B-5- B), while they were at par with the control inbredline CML216. Plants were regenerated from all the inbred lines except CML443 and were successfully ac climatized and grown to maturity. CML395 was the best regenerable line with significantly (p<0.05) h igher regeneration efficiency of 109.3%. It was concluded that CML395, CML216 and CML442 can be used in in vitrogenetic transformation. Keywords: Elite tropical maize inbred lines, immature zygotic embryos, in vitro culture, plant regeneration, somatic embryos.