Abstract: Several wheat cultivars were transformed in planta by Agrobacterium tumefaciens and numbers of transformants were gained. A mutant with high tillering was found in the transmants of the wheat cultivar Lumai 21. The mutant was identified with part of T-DNA sequence by PCR and Southern blot and displayed a recessive gene mutation. Mutant plants of T3 were found with part of T-DNA sequence by PCR. This indicated the mutant was created by T-DNA. Primary analysis suggested that the mutation gene is relative to plant response to temperature. Tiller number of the mutant increased much more than that of the wild parent with temperature decrease.