Abstract: 【Objective】The objective of this study is to conduct mapping genes conferring resistance to physiological race 4 of head smut disease in sorghum and screen the molecular markers linked to the resistance genes, in order to lay a foundation for sorghum resistance breeding against the head smut in future.【Method】To build F2 populations, the material 961541 as a female, which is immune to physiological races 1, 2, 3, and 4, was crossed with V4B which is immune to physiological races 1, 2, and 3 and sensitive to race 4 and PI550607 which is sensitive to physiological races 1, 2, 3, and 4. The seeds were inoculated with soil containing suitable chlamydospores at sowing time, and the disease incidence of the parents, F₁ progenies and F₂ population was investigated at heading stage. The localization of resistance gene was studied by SSR technology and bulked segregation analysis (BSA) method using the 961541/V4B population.【Result】The results of field investigation showed that, for the cross combination 961541/V4B, the morbidities of 961541 and the F₁ progeny both were 0, and that of V4B and F₂ population were 21.5% and 7.25%, respectively. For another cross combination 961541/PI550607, the morbidities of PI550607 was 64.81%, and that of the F₁ progeny, F₂ population were 0 and 5%, respectively. The fitness test indicated that, for the two F₂ populations, the ratio of resistance quantities to sensitive quantities both were conformed to 15:1(χ²=0.201, 0.322, P>0.05), which implied that the resistance genes to head smut race 4 should be controlled by 2 non-allelic genes. The linkage analysis showed that, among the total 274 pairs of SSR primers, 53 pairs showed different amplification between the parents. Then screening of the specificity primers among the 53 pairs were conducted between the resistance pool and the sensitive pool, while only Xtxp325 on chromosome 1 was specific. The banding pattern of resistance pool was the same as 961541, and the sensitive pool was as the material V4B. Linkage mapping with the 5 pairs primers (Xtxp325, Xtxp302, Xtxp32, Xtxp340, Xtxp248) showed that the overall length of linkage map was 355.3 cM, the genetic distance between Xtxp325 and the resistance gene (Shs1) was 27.7 cM.【Conclusion】The resistances to physiological race 4 of sorghum head smut might be controlled by two mutual independent non-allelic genes. The linkage map was good correspondence with the public maps, and which the overall length was 355.3 cM. The resistance gene Shs1 of head smut race 4 is located on No. 1 chromosome of sorghum, and the genetic distance is 27.7 cM from the primer Xtxp325.

Key words: sorghum, head smut, resistance gene, gene mapping