Studies On Establishment And Optimization Of The Regeneration System Of Foxtail Millet

This paper was about using mature embryos, leaves and infloresence of millet (CV jingu 21)as explants, and medium MS and N6 as the basic medium. Different kinds and proportions of auxin and cytokinin were added in the process to study callus induction, subculture and differentiation. The results showed as followed:1. NAA was better than 2,4-D in the process of callus induction of mature embryo. The callus induction rate was highest when the concentration of NAA was 4.0-4.5mg/L. Neither too high or too low of hormone concentration had any benefits for the callus induction. The callus quality could be improved when low concentrations of CTK was added into callus induction medium; Callus induction rate of medium N6 was slightly higher than medium MS.2. It was significant that the Callus induction of millet leaves was harder extremely than both mature embryos and infloresence. The study also showed that NAA had no use for callus induction of millet leaves; And 2,4-D used to induct callus had no effective results only if the concentration was more than 2.0mg/L. All this results were consistent with the previous studies. In the mean time, leaf callus had better quality when 2.25mg/L 2,4-D was used along with 0.5mg/L KT in induction; and better performance in the medium MS than in N6, which was different from callus induction of mature embryo. The growth status of leaves affected callus induction, for example, young leaves planted a week and leafroll at the top of stem planted for weeks could both induct callus. Relatively, the size of leaves had few effect for callus induction, while the larger incision was better to induct callus.3. Infloresence was one of the most popular explants used in millet tissue culture currently. Therefor its regeneration system had been established basically. Callus induction of infloresence was easier than the former two, and its differentiation rate was also the highest. Stable callus culture system TYPE I and TYPEII had obtained in this experiment; It’s been proved that adding 2.25mg/L 2,4-D and 0.5mg/L KT into the medium could induce better quality TYPE I callus, then translated into embryonic callus(TYP II) after transferred to the medium MS containing TDZ and cultured two generations. Infloresence age had greater impact on callus induction rate. It would be the best material for callus induction when its age reached 12 weeks. Callus induction rate decreased significantly with the increase of age of the infloresence, induction rate was zero when infloresence age was 16 weeks; The induction rate could also be improved by cutting the infloresence from 13 weeks to 15 weeks.4. Adventitious buds could be produced by TYPE I callus on the medium MS containing TDZ at the concentration of 0.5-2.0mg/L and adventitious buds grew best when the concentration of TDZ were 1.0-1.2 mg/L; For TYPE Ⅱ callus subculture, the recycle of 6-BA for 3 times and TDZ for 2 times could receive the best effect; On the other hand,12mg/L AgNO3 in the medium could improve the differentiation rate of embryonic callus significantly.