Comparison of Induction and Regeneration of Embryogenic Callus Initiated from Immature Embryos and Seedling-Derived Young Leaf Segments of Maize

【Objective】 Using immature embryos and seedling-derived leaf segments of maize inbred lines that are commonly used in breeding as explants,the difference and correlation between these two explants in terms of their callus induction and regeneration were studied.The aim of this study is to provide a protocol for the establishment of an efficient and stable regeneration system in maize using leaf segments as an alternative explant.【Method】 Six inbred lines of maize(Zea mays L.) that routinely used in breeding were tested in this study.The initiation,maintenance and differentiation of callus from their immature embryos and seedling-derived leaf segments were compared.The effect of 2,4-D on primary callus induction of different explants from all these six lines was studied.The callus induction and differentiation frequency were recorded,and the callus morphology was also observed.【Result】 Different explants required different concentrations of 2,4-D to induce callus formation.Generally,the leaf segment was more difficult to induce and also required higher concentration of 2,4-D compared with immature embryos.The callus induction and differentiation rate of these two explants of all six genotypes were very different although that of the same genotype were similar.【Conclusion】 Three genotypes,Qi 319,Mo17 and Luyuan 92,were selected after screening through six lines for their performance in higher callus induction rate and excellent morphology.