The Selection Of Glyphosate-resistant Mutants And Preliminary Study On Mature Embryo Culture In Maize

Weeds are main hazard in maize early stage of growth, and glyphosate is a high-efficient and low-toxicity herbicide to be used widely, its advantage is unusual among herbicides as after budding it can kill all the plants. To select glyphosate-resistant mutants and breed glyphosate-resistant strains has important meanings. Screening work was carried out by combining physical and chemical mutagenesis selection with somatic cell selection.The results of physical and chemical mutagenesis selection indicated that inbred line 112 which was mutagenized appeared many variations in current generation; Physical mutagenesis could lower the heights of stem and tassel site evidently; 900ppm glyphosate was a more ideal spraying concentration for screening mutant and killing weeds; we obtained glyphosate-resistant regenerated plants which were no progenies.In the procedure of somatic cell selection, firstly, calli were induced with immature embryos of maize; Secondly, the propagated calli were subcultured in N6 medium with glyphosate three times for selecting glyphosate-resistant calli; thirdly, the resistant calli were maintained on glyphosate-free medium for restoration culture three times; finally, glyphosate-resistant regenerative plants were induced with the resistant calli. Two kinds of screening measures were adopted in somatic cell selection: equal concentration and gradient selection. Initiative and maximal selection concentration were chosen according to mortality of calli and proportion of II type calli. Three different screening concentrations were devised in every screening method. In the equal concentration selection, three concentrations of glyphosate(300ppm-300ppm-300ppm, 400ppm-400ppm-400ppm, 500ppm-500ppm-500ppm) were devised; in the gradient selection , the concentrations of glyphosate were from low to high(150ppm-200ppm-300ppm, 200ppm-300ppm-400ppm, 300ppm-400ppm-400ppm). Compared with equal concentration selection, gradient selection was better for keeping embryogenic calli and the differentiation of calli.Resistant calli from selecting and restoration culture and calli of control were cultured on the medium with glyphosate ,the result showed that resistant calli had...