Abstract:The growth difference of weeds in stubble fields of 10 varieties of wheat, which responses to different genotypes, is analyzed with an improved method based on the bioassay of inhibitive circle in fields. The preliminary study shows that in stubble fields of wheat materials belonging to related varieties from different or same genotype the growth of weeds differ significantly, which means evident variation of allelopathic genes while happening causing a constant heredity. When the biomass of weeds in the stubble field of the accession "Fengchan 3" is considered as the control the rest almost exhibit certain effect of inhibition on the growth of weeds in counterpart fields. The positive correlation exists in the biomass of weeds in 10 cultivars of wheat stubble fields and the resorting time of remnant stubbles by the analysis of step regression. Meanwhile, the efficient days are verified for 3-29 days when evaluated the effect of stubbles on the growth of weeds. After that the biomass of weeds will begin to increase. In the end the growth of weeds will come to stabilization. With the change of stubbles left period the allelopathy intensity of wheat stubbles with different genomes will decline uniformly and gradually, and the mean effective period of inhibition on the growth of weeds is 21, 24, and 25 d respectively. The results on genomes explain perhaps that the genetic elasticity is available for an enhancing trend of the allelopathic effect in wheat during the long evolution of wheat in the genome change from diploid, tetraploid to hexaploid.