Effects Of Fhb1 On Fusarium Head Blight Resistance And Agronomic Trait Performances Of The Wheat Cultivars Adapted To The Yellow-Huai River Valley Winter Wheat Zone

Fusarium head blight?FHB?is a fungal disease of global importance in wheat?Triticum aestivum?.It not only causes significant decrease in production and end-used quality,but also contaminates wheat grains due to Fusarium toxins that can endanger the health of the humans and animals.With the global warming and the changes of cropping systems,the occurrence of FHB in China has expanded from the Middle and Low Yangtze Winter Wheat Zone?MLWZ?to Yellow-Huai River Valley Winter Wheat Zone?YHWZ?.As present,FHB has become one of the main diseases in YHWZ.The development of disease resistant cultivars is one of important approaches to solve this problem.We have previously confirmed that introduction of Fhb1 resistance alleles from different donors can significantly increase the FHB resistance;however,the effects of genetic backgrounds on Fhb1 performance and whether Fhb1 has negative influence on agronomic traits remain unclear.In this study,10 BC₂ populations were developed by crossing dwarf-male-sterile?DMS?-Zhoumai16 to 5 Fhb1 donors?Ningmai 9,Shengxuan 6,Sumai 3,Jianyang 84 and Ningmai 13?and backcrossing to Zhoumai 16 and its derivative cultivars?Lunxuan 136 and Lunxuan 13?using marker-assisted backcrossing method.FHB resistance was evaluated using the natural assessment to 10BC₂F₂ populations in the field and single-floret inoculation assessments to 4 BC₂F_2:3 populations in the greenhouse.Eight agronomic traits,including plant height,spike number per plant,spike length,spikelet number per spike,sterile spikelet per spike,kernel weight per spike,kernel number per spike and thousand-kernel weight,were investigated for the 10 BC₂F₁ and BC₂F₂ populations,respectively.The main results showed that:1.In the plants carrying the homozygous Fhb1 resistance genotype?Fhb1-R?had higher FHB resistance than those with the homozygous Fhb1 susceptibility genotype?Fhb1-S?in both Lunxuan 136and Lunxuan 13 backgrounds;2.The Fhb1-R plants from different donors had fewer infected spikelets and lower disease severity than their respective recurrent parents;3.The Fhb1-R plants from the same donors had different resistance under different genetic backgrounds.When Lunxuan 136 was used as the recurrent parent,the Fhb1-R plants had significant fewer infected spikelets per spike than the Fhb1-R plants produced using Lunxuan 13 as the recurrent parent,indicating that the genetic backgrounds of Fhb1 impact the expression of FHB resistance;4.The progenies carrying the Fhb1-R from different donors showed significantly difference in their resistance to FHB,among which the plants containing the Fhb1-R from Shengxuan 6 had the best FHB resistance;5.No consistent and significant phenotypic differences were observed for the eight agronomic traits between the Fhb1-R or Fhb1 heterozygosity plants?Fhb1-H?and the Fhb1-S plants in each genetic background.This indicates that Fhb1 does not have significantly negative impact on the main agronomic characters.Results of this study provide important information in the improvement of the FHB resistance by introgressing Fhb1 resistance allele into the cultivars adapted to YHWZ.