Effects Of Fhb1,Fhb2 And Fhb5 On Fusarium Head Blight Resistance In The Yellow-Huai River Valley Winter Wheat Zone

With changes in climates and cultivation system,Fusarium head blight（FHB）of wheat has spread northward,and become one of the main diseases in the Yellow-Huai River Valley Winter Wheat Zone（YHWZ）.Due to the difference in ecological types,it is difficult to directly grow FHB-resistant wheat cultivars from the Middle and Lower Yangtze River Valleys Wheat Zone in the YHWZ.Therefore,it is necessary to develop wheat cultivars with resistance to FHB in this region.Marker-assisted selection（MAS）can not only help to get rid of the difficulty of phenotypic evaluation,but also accelerate the breeding process.In this study,six BC₂ populations were developed by crossing dwarf-male-sterile（DMS）-Zhoumai 16 to six Fhb1 donors（i.e.,Sumai 3,Ningmai 9,Ningmai 13,Jianyang 84-1,Jianyang 84-2,and Jianyang 798-2）and backcrossing to Zhoumai 16and its derivative cultivar Lunxuan 136 using the marker-assisted backcrossing method.The resistance to FHB of the BC₂F₃ and BC₂F₄ lines was tested in these populations in order to elucidate the effects of Fhb1 on FHB resistance under the genetic background of Lunxuan 136 and select the FHB-resistant lines.Using the wheat×maize induced haploid technology,the DH lines were developed from the BC₃F₁ population by crossing the BC₂ plants with Sumai 3 as the donor and Lunxuan 6 as the recurrent parent.The effects of pyramiding genes Fhb1,Fhb2,and Fhb5 on FHB resistance were evaluated on these DH lines.The main results are shown below:1.Sixty out of 161 BC₂F₃ lines were more resistant to FHB than Huaimai 20,the moderately susceptible control,in three environments,and the number of infected spikelets and disease severity decreased by 2.02 and 10.87%on average.2.A total of 122 BC₂F₄ lines derived from 60 BC₂F₃ lines were evaluated,and 93of them had lower infected spikelets and disease severity than Huaimai 20,suggesting that the resistance of the selected BC₂F₃ lines were inherited to the next generation.Among them,36 lines showed comparable or better resistance to FHB than the moderately resistant control Yangmai 158.3.Under natural infection,the DH lines carrying gene Fhb5 had better FHB resistance than those carrying genes Fhb1 and Fhb2,whereas the DH lines carrying gene Fhb1 was more resistant to FHB than the other two genes under artificial inoculation.4.Pyramid of genes showed better FHB resistance than single gene.The DH lines carrying Fhb1+5 and Fhb2+5 had fewer infected spikelets and lower disease severity than those carrying Fhb1+2 under natural infection,and the DH lines carrying Fhb1+5also showed higher FHB resistance than the other two types of lines under artificial inoculation.Results of this study suggest that Fhb1 can effectively improve resistance to FHB in the YHWZ and the resistance to FHB can be stably inherited to the next generation.Pyramiding FHB-resistance genes is beneficial to develop wheat cultivars with better resistance to FHB.