Construction And Identification Of Fusarium Head Blight Genetic Population Of Wheat-thinopyrum Intermedium Derivatives

In this study,the Thinopyrum intermedium introgression line HS2-32 with secondary resistance to scab was crossed with spring wheat varieties Longmai 33 and Longmai 35in Heilongjiang Province,and the genetic population was constructed through positive and negative cross,backcross and selfing.By means of scab resistance detection and molecular cytogenetic detection,the genetic population and new spring wheat breeding materials that can be used in wheat scab resistance breeding were created and screened.Seven genetic populations were constructed in this study,including three recombinant inbred lines（RIL）populations,HS2-32/Longmai35 F₃,Longmai 35/HS2-32 F₃ and Longmai33/HS2-32 F₁ populations,and four backcross（BC）populations,Longmai35/HS2-32//HS2-32BC₁F₂,Longmai35/HS2-32//Longmai35 BC₁F₂,Longmai33/HS2-32//Longmai 33 BC₁F₁ and Longmai 33/HS2-32//HS2-32BC₁F₁populations.Using the resistance inoculation assay of FHB,a total of 208 materials with resistance level 2 or higher and 95 materials with susceptible level 4 were obtained in the HS2-32/Longmai35 F₃ and Longmai35/HS2-32 F₃ populations.BSRseq assays for disease resistance in mixed pools were performed on F₄ plants of resistant and susceptible materials from both populations,and the results showed that trait-related variants were located on chromosome 4B,and it was hypothesized that the candidate variants associated with disease resistance traits existed on this chromosome.The results of morphological and protein content tests showed that among the F₂ and F₃ populations of HS2-32 and Longmai 35 forward and backward crosses,21 materials had good agronomic traits,such as strong stemwithout falling and high seed setting rate.A thousand grain weight was more than 40g in four plants thatthe highest material was40.49 g.The grain protein content of 15 lines reached more than 15%.The results of cytological and molecular marker identification showed that the number of chromosomes of the parents HS2-32,Longmai 35,Longmai 33 and the various types of population materialswere all 42and their chromosome group were stable.There was no target band consistent with Th.intermedium in HS2-32 and hybrid offspring,but the specific polymorphic bands were observed between HS2-32 and the resistant pool materialfrom Longmai35/HS2-32 F₃.The results of fluorescence in situ hybridization showed that FISH karyotypes of chromosome from the five materials identified in this study were not identical to the Chinese Spring chromosome karyotypes.There were 6-8 differential chromosomes.The resistant population and spring wheat breeding materials selected and identified in this study can be further selected for high generation and provide germplasm resources for wheat breeding in the spring wheat region of Heilongjiang Province.