A set of T. aestivum-L. elongatum substitution lines were studied on yellow rust resistance at seedling stage, inheritance of the resistance and esterase-5 (Est-5) analysis. The results demonstrated that L. elongatum carried a new yellow rust resistance gene(s), which was dominant and located on chromosome 3E of L. elongatum. The biochemical locus encoding Est-5 was also located on chromosome 3E, and was tentatively named Est-E5, which was co-segregant with the Yr gene(s) in wheat background. In addition, the transmission frequencies of chromosome 3E in 3A/3E and 3D/3E hybrids selfing were significantly higher than that of chromosome 3E in 3B/3E hybrid, which was probably due to the difference on genetic relationships among A, B, D and E genomes. A set of T. aestivum-L. Elongatum substitution lines were studied on yellow rust resistance at seedling stage, inheritance of the resistance and esterase-5 (Est-5) analysis. The results prototype that L. elongatum carried a new yellow rust resistance gene (s), which was dominant and located on chromosome 3E of L. elongatum. The biochemical locus encoding Est-5 was also located on chromosome 3E, and was tentatively named Est-E5, which was co-segregant with the Yr gene s) in wheat background. In addition, the transmission frequencies of chromosome 3E in 3A / 3E and 3D / 3E hybrids were significantly higher than that of chromosome 3E in 3B / 3E hybrid, which was probably due due to the difference on genetic relationships among A, B, D and E genomes.