Studies On Callus Induction And Differentiation With Diverse Explants Of Maize

Mature embryos of hybrid maize type-xianyu335, adventitious shoots and aseptic seedlings were used as explants in this experiment, while medium MS and N6were used as the basic medium. Auxin2,4-D and auxin NAA as well as cytokinin6-BA were added to the culture medium in the process of cultivating. In addition, callus induced by mature embryos was cultured in differentiation. Then five different genotypes of mature embryos-B73, B105, B113, Ji818and Mo17which used as explants were studied and compared with each other. The results showed as followed:1. The ability of callus induction by mature embryo added auxin2,4-D was better than that of mature embryo added auxin NAA. Induction rate of medium with cytokinin6-BA was high, but browning phenomenon was serious. Callus induction rate of medium N6was slightly higher than that of medium MS, but this difference was very small. The quality of callus induced by auxin2,4-D was better than that of auxin NAA, especially at the concentration of2.0mg/L which induced the best quality of callus.2. Maize seed after48hours pretreatment was one of the most conducive ways to callus induction by mature embryos. Moreover, adding4.0mg/L auxin2,4-D in the sterile water pretreated was also conducive to callus induction by mature embryos. In contrast, silver nitrate was not conducive to callus induction, meanwhile the proline and casein hydrolysate would lower the callus induction rate.3. Callus induction rate was basically the same in both low concentrations of auxin2,4-D and NAA, however the difference was obviously great under the high concentration of auxin2,4-D and NAA. The ability of callus induction by mature embryo added auxin2,4-D was better than that of mature embryo added auxin NAA. The bud callus induction rate reached the highest in the medium MS with3.0mg/L auxin2,4-D and the medium N6with1.0mg/L auxin2,4-D. Medium N6was more beneficial to callus induction than that of medium MS. 4. The ability of callus induction by leaf2,4-D was better than that of NAA. Callus induction rate under different concentrations of leaf2,4-D was low and these differences were small. Leaf callus induction rate in the medium MS was significantly higher than that of medium N6. The result illustrated that medium MS was suitable for the leaf callus induction.5. Five different genotypes of mature embryos could induce callus in the induction experiment with1.0mg/L medium N6and8.0mg/L auxin2,4-D. From the analysis of the population mean, callus induction rate of mature embryo B113was the highest, followed by mature embryo B73and Ji818. Callus induction rate of mature embryo B105and Mo17was the lowest.6. The power rate and germination rate were similar in both cytokinin6-BA and cytokinin KT, but the rate of browing in cytokinin KT was obviously lower than that of cytokinin6-BA. Under the conditions of different cytokinin6-BA concentrations and the same auxin concentration, the lower the cytokinin concentration was, the higher the callus induction rate was. The callus induction rate of mature embryos was the highest in the dose of1.5mg/L auxin NAA and2.0mg/L cytokinin.