Study On The Selection Of Cell Mutant Lines Resistant To Glyphosate In Cotton

Weeds are main hazard in cotton early stage of growth,and glyphosate is a high-efficient and low-toxicity herbicide to be used widely,the advantage is unusual among herbicides as after budding it can kill all the plants.To select glyphosate-resistant mutants and breed glyphosate-resistant cotton has important meanings.Screening work was carried out by somatic cell selection.Firstly,calli were induced with hypocotyls of cotton;Secondly,the propagated calli were subcultured in 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 methods were adopted in somatic cell selection:equal concentration and gradient selection.Three different screening concentrations were devised in every screening method.In the equal concentration selection,three concentration 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).The experimental results showed the resistance of different cultivitars to glophosate was different.The highest resistant concentration to glophosate for Y668 was 400ppm, and for YZ1 and C201 were 500ppm.With the increase of the glophosate concentration,the relative growth of callus decreased and its colour appeared brown.The plantlets of the control and from the screened mutant were cultured on medium with glophosate.The results showed that the rooting rate was higher on medium without glophosate.On the medium with glophosate,the rooting rate of mutant was higher than 20%,but the control was zero.Therefore,the resistance of mutant was through persistent. 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 resistance to glyphosate to some extent.The regenerative plants from resistant calli and control plants were sprayed with glyphosate solution for testing the resistance,the result showed that control plants were all dead,three of resistant regenerative plants survived.It could infer that those survival plants were glyphosate-resistant mutants.By spraying the field density of glyphosate to glyphosate-resistant mutants,it discovered in the physiological biochemistry level's performance:The comparison is spraying the field density glyphosate complete casualties;But the glyphosate-resistant mutants,regardless in leaf blade's chlorophyll content and soluble protein's content, its change basically maintains invariable,the color which displays externally with it is also consistent.