Effects of the Fhb1 gene on Fusarium head blight resistance and agronomic traits of winter wheat

Abstract

The gene Fhb1 has been used in many countries to improve wheat Fusarium head blight (FHB) resistance. To make better use of this gene in the Yellow-Huai River Valleys Winter Wheat Zone (YHWZ), the most important wheat-producing region of China, it is desirable to elucidate its effects on FHB resistance and agronomic traits in different genetic backgrounds. Based on a diagnostic marker for Fhb1, six BC2 populations were developed by crossing dwarf-male-sterile (DMS)-Zhoumai 16 to three Fhb1 donors (Ningmai 9, Ningmai 13, and Jianyang 84) and backcrossing to Zhoumai 16 and Zhoumai 16's derivative cultivars (Lunxuan 136 and Lunxuan 13) using marker-assisted backcross breeding. The progenies were assessed for FHB resistance and major agronomic traits. The Fhb1 alleles were identified using the gene-specific molecular marker. The plants with the Fhb1-resistant genotype (Fhb1-R) in these populations showed significantly fewer infected spikelets than those with the Fhb1-susceptible genotype (Fhb1-S). When Lunxuan 136 was used as the recurrent parent, Fhb1-R plants showed significantly fewer infected spikelets per spike than Fhb1-R plants produced using Lunxuan 13 as the recurrent parent, indicating that the genetic backgrounds of Fhb1 influence the expression of FHB resistance. Fhb1-R plants from the DMS-Zhoumai 16/Ningmai 9//Zhoumai 16/3/Lunxuan 136 population showed the highest FHB resistance among the six populations and a significantly higher level of FHB resistance than the moderately susceptible control Huaimai 20. No significant phenotypic differences between Fhb1-R and Fhb1-S plants were observed for the eight agronomic traits investigated. These results suggest that it is feasible to improve FHB resistance of winter wheat without reducing yield potential by introgressing Fhb1 resistance allele into FHB-susceptible cultivars in the YHWZ.