Four different backcrossing methods were designed and 23 near isogenic lines (NILs) of 22 linkage groups were obtained using Hb as recurrent parent, the mutant gene lines which held markers as donor parents. Eleven of them had been mated with the recurrent parent for 10 times, and the others for 7∼8 times. The NILs of other 6 linkage groups are under way and had been backcrossed to the recurrent for 3∼4 times. These NILs will act important roles in the construction of molecular linkage map and gene location and positional cloning.