Identification And Molecular Cytological Analysis Of Fusarium Head Blight From Wheat-rye Derivative Offspring

Rye(Secale cereale;2n=2x=14,RR)is one of the sibling species of wheat,and contains many excellent genes for improving wheat.The Rye plant is tall,has a large number of spikelets,and has strong environmental adaptability.It has the advantages of drought resistance,cold tolerance,poor tolerance,acid and alkali resistance,and is rich in resistance genes.It is more resistant to diseases such as stripe rust,smut,yellow dwarf,leaf spot and sheath blight than wheat.It is one of the important heterologous gene donors for wheat.Tritice is a new crop that is artificially synthesized by the hybridization of wheat and rye.In particular,the selection of octoploid rye(AABBDDRR,2n=56)not only maintains the high yield and good quality of wheat,but also has good grain fullness,and also combines the disease resistance and stress resistance of rye.Fusarium Head Blight(FHB)is a global wheat-based disease.In order to find out whether the rye contains the anti-FHB disease gene,the experiment used the hybridization of Mexican rye and common wheat W770 B to obtain 30 stable genetically derived progeny materials.It was identified by single instillation and combined with cytology.Identification of resistant materials by in situ hybridization and molecular markers.Below are key research findings:1.The results of single-infusion inoculation of FHB showed that the average severity of parental rye was 2.1,showing moderate resistance;the average severity of W770 B was 4.0,showing high sensitivity.Among the 30 wheat-rye-derived offspring,7 materials reached the medium resistance level,accounting for 23.3% of the tested materials;8 materials showed moderate sensitivity,accounting for 27.0% of the tested materials;15 were susceptible,accounting for 50.0% of the test materials.The results of agronomic traits showed that 30 agronomic traits of the offspring were generally better than the parents.The plant height decreased significantly and the lodging resistance increased.The thousand-kernel weight and tiller number were significantly higher than the parents,and the comprehensive agronomic traits performed well.2.The 12-5-1 cytogenetic study of the derivative strain of resistance to scab showed that the root tip cells contained 42 chromosomes 2n=42.The pollen mother cells were reduced in the first division of the metaphase cytology,and the chromosomes were normally paired to form.21 bivalents,2n=42=21II,and can be separated normally.Using the rye genome as a probe to identify the 12-5-1 genome in situ hybridization(GISH),it was observed that the two chromosome ends of the wheat had yellow-green signals,indicating that the rye gene was contained in 12-5-1.A small fragment translocation occurred in hybridization with rye.Using the specific SCAR marker of 1RS,only the specific target band wasamplified in 12-5-1.Using the primers of the long arm and short arm of 21 chromosomes of wheat for SSR analysis,only 3 pairs of primers(Xgwm31,Xgwm11,Xgwm550)on 1BS could not amplify the target band,and the remaining primers amplified their respective chromosome bands.Thus,it can be proved that 12-5-1 is a 1RS·1BS/1BL small fragment translocation system.The identified wheat-rye-derived materials with resistance to FHB were well genetically stable and compensatory.Making full use of the excellent trait genes of rye and wheat improvement provided excellent intermediate materials and enriched wheat germplasm resources.