Resistance of imidzolidone-resistant oilseed rape to nonselective herbicide imazethapyr.

To evaluate the resistance of imidzolidone-resistant oilseed rape to nonselective herbicide imazethapyr and its application value for the selection of imidzolidone-resistant oilseed rape varieties which are environmentally biosafe,the concentration gradient experiment was carried out to investigate the effect of various concentrations of imazethapyr on the seedling growth of oilseed rape by measuring plant height,leaf number,maximum leaf area,and dry matter weight,etc.on day 10,day 20,day 35,day 50 and day 65 after spraying herbicide imazethapyr.The effects on the agronomic,economic and quality properties of imidzolidone-resistant oilseed rape were analyzed as well by determination of the single plant biomass,oil content,protein content,glucosinolate content and fatty acid composition in rapeseed.The result showed that high concentration of imazethapyr inhibited the growth of leaf and main stem markedly,sequentially restrained dry matter accumulation of aboveground part and the agronomic and economic properties of mature oilseed rape.Inhibition by imazethapyr at concentration range from 45 to 180 g/hm2,ai.to oilseed rape at ealy seedling stage was exhibited at ealy seedling stage,however,the rape growth began to resume,with LAI and seedling height being 92.94% and normal to CK(imazethapyr-free) at day 35 and day 65,respectively.No undesirable effect appeared in imidzolidone-resistant oilseed sprayed with nonselective herbicide-imazethapyr.The lowest effective dose(ED90) of herbicide imazethapyr was 45 g/hm2,ai.,and the highest was 108.59-190.77 g/hm2,ai.,which indicated that the resistance effect of nonselective herbicide imazethapyr on imidzolidone-resistant oilseed rape was quite strong.