Screening And Identification For Resistance To Fusarium Head Blight Of Wheat-Leymus Mollis Derivative Lines

At present,the Fusarium Head Blight(FHB)have serious influence on global wheat production.Breeding disease-resistant varieties is a more effective strategy than that of using chemical agent or changing cropping system to reduce disease.Resistant germplasm is the prerequisites for breeding resistant varieties.Distant hybridization is know as an effective method of introducing excellent genes of alien species into common wheat to enrich resistant genes.Leymus mollis was an excellent resource for wheat genetic improvement because of its characteristics of resistance to FHB,short stalk and barren resistance.In this study,eight-one wheat-Leymus mollis derived lines,which were selected from the progenies of the cross between common wheat or durum wheat and octoploid Tritileymus,were investigate and evaluate the resistance to disease by the method of single flower infusion,and the resistant materials were identified by using cytogenetic observation,genomic in situ hybridization(GISH),fluorescence in situ hybridization(FISH)and molecular marker.The results are as follows:1.Screening of resistance to FHB in wheat-Leymus mollis derivativesIn 2017 and 2018 planting season,81 wheat-Leymus mollis derivatives were investigated twice for evaluating the FHB resistant.The result showed that there are 5 lines expressing highly resistant,10 lines showing moderately resistant,47 lines demonstrating moderately susceptible and 19 lines performing highly susceptible,respectively.The 5 highly resistant lines were 17Y7,17Y9,17Y10,17Y12 and 17Y13.Through analysis the dynamic change of the rate of diseased spikelet,we speculated that these 5 materials have good resistance to FHB expansion.The investigation of agronomic traits demonstrated that lines 17Y7,17Y9,17Y12 and 17Y13 were mainly showing dwarf,and the panicle number per plant was significantly higher than that of parents.The spike lengh,1000-kernel weight,kernel number per spike and spikelet number of 17Y10 were significantly increased compared with parents.In addition,the seed quality of 17Y10 and 17Y13 was mesaured by DA7200 multi-functional near-infrared analyzer,and the result showed the protein content of the 2 lines was significantly higher than that of the parent 7182.It is indicate that these 5 germplasm are of valuable utilization for wheat improvement not only in FHB resistance,but also in yield and quality.2.Molecular and cytological studies on resistant wheat-Leymus mollis derivatesCytological observation of the five disease-resistant materials showed that 17Y7,17Y9,17Y12 and 17Y13 have 44 chromosomes,and 17Y10 have 42 chromosomes,respectively.Genomic in situ hybridization(GISH)identification of the root tips cell showed that 17Y7,17Y9,17Y12 and 17Y13 contained two Ns chromosomes plus two translocated chromosomes involving wheat and Leymus mollis' Ns genome,and presumed that they are wheat-Leymus mollis addition-translocation lines.17Y10 contained two wheat chromosomes translocated with Ns chromosomes of Leymus mollis,and presumed that it is a wheat-Leymus mollis translocation line.Identification of fluorescence in situ hybridization(FISH)and SNP marker for 17Y13 showed that the translocation occurring between wheat 3D chromosomes and Leymus mollis 5Ns chromosomes.In conclution,the excellent agronomic traits of 17Y10 and 17Y13,such as valuable FHB resistance,dwarf and high protein content,which should be derived from Leymus mollis,can be used in the breeding progrom of wheat FHB resistant,yield and quality improvement as an important candidate genes in the future.