不同培养基对小麦×玉米杂种胚离体培养成苗的影响

Effect of Different Culture Media on Haploid Plantlets Production from the Wheat×Maize Cross

为了提高小麦远缘杂交单倍体胚植株再生频率,剥取胚龄16～20d的小麦单倍体胚无菌条件下接种到不同配方的培养基。结果表明,直径<500μm的小胚在1号培养基、直径>500μm态的较大胚于2号培养基能一步成苗直接发育成具有丛生芽和健壮根的幼苗;若把丛生幼芽分开后分别转移到1/2 MS基础培养基,则可分化增殖为多株麦苗。小胚培养基配方为:1/2MS+0.1mg.L-12,4-D+0.2mg.L-1BA+300mg.L-1LH(水解乳蛋白)+50g.L-1蔗糖+7g L-1琼脂,pH=5.8,成苗率71%;大胚培养基配方为:1/2 MS+0.1mg.L-12,4-D+0.2mg.L-1BA+30g.L-1蔗糖+7g.L-1琼脂,pH值5.8,成苗率83%以上,以上培养基维生素部分为正常MS培养基维生素加入量的2倍。适宜于小麦单倍体胚再生和繁殖的生长素效果:2,4-D>IBA>IAA,培养基加入2,4-D后经继代培养途径形成单倍体植株生长旺盛,根系发达,增加了单胚再生植株数和植株丛生苗数量,有利于大幅度提高胚成苗率以及染色体加倍效率,从而提高远缘杂交单倍体育种水平,缩短小麦新品种生产周期。

The significance of haploid plants as genetic and plant breeding tools has been recognized for a long time.The purpose of this study was to improve the production ratio of haploid plantlet in wheat × maize hybridization.The immature haploid embryos of 16~20d after pollination were dissected under sterile environment,and placed onto different compositions of culture media.The result indicated that the best medium for the smaller embryos with the diameter 500um was 1/2MS ＋0.1mg·L-12,4-D＋0.2mg·L-1BA ＋ 300mg·L-1 LH（Lactalbumin Hydrolysate） ＋ 50g·L-1sucrose ＋7 g·L-1agar,pH=5.8,and the best medium for the bigger embryos with the diameter 500 um was 1/2 MS ＋0.1mg·L-12,4-D＋0.2mg·L-1 BA ＋ 30 g·L-1 sucrose ＋7 g·L-1 agar,pH=5.8.The embryos in the two kinds of media could be developed into plantlets directly with strong shoots and roots.Plantlets production percentage of the smaller embryos was 71%,and that of the bigger embryos was 83%.For all the MS media,the amount of vitamin was twice as much as in the normal MS culture medium.The result also showed that the type of the auxins appropriate for plantlets regeneration was in the order of 2,4-D IBA IAA.The plantlets coming from the medium adding 2,4-D grew more vigorous and had more roots.Detaching the induced cluster buds and transferring to 1/2 MS greatly increased the number of seedlings.The media adding 2,4-D and subculture of haploid embryos enhanced plantlets regeneration rate and chromosome doubling efficiency to some extent,substantially improved DH（doubled haploid） production efficiency of distant hybridization,and shortened production cycle for new wheat cultivars.