Screening And Molecular Cytogenetic Characterization Of New Germplasm Of Wheat-Leymus Mollis Resistant To Fusarium Head Blight

Leymus mollis（Trin.）Hara（2n=4x=28,Ns Ns Xm Xm）,one perennial herb of the genus Leymus（Leymus Hochst）with many excellent agronomic traits such as dwarf stems,large spikes and resistance to a variety of fungal and bacterial diseases.In China,distant cross between wheat and L.mollis were carried out in the 1980 s and many derivatives with high resistance to stripe rust were obtained,while little research has been reported on wheat-L.mollis wheat derivatives with resistance to Fusarium Head Blight（FHB）.In this study,30wheat-L.mollis derivatives were tested in filed and greenhouse environments for FHB resistance and three derivatives were selected for FHB resistance.The chromosome composition and source of resistance to FHB were investigated using molecular cytogenetic methods,with a view to providing candidate germplasm for genetic improvement of FHB resistance in wheat.1.Thirty wheat-L.mollis derivatives were identified by single-flower drip injection,from which three derivatives（18DM26,18DM30 and 18DM134）were selected for high resistance to FHB.2.The cytological results showed that,at mitotic metaphase,18DM26,18DM30 and18DM134 contained 44,44 and 42 chromosomes,respectively.At meiotic metaphase I and meiotic anaphase I,the homologous chromosomes pairing and segregation situation is normal,indicating that the three derived lines were genetically stable.In situ hybridization,liquid microarray(Geno Baits^?Wheatplus Ph)and molecular markers showed that 18DM26 is a wheat-L.mollis additional transposition line,contained forty complete common wheat chromosomes,two complete 3Ns chromosomes and two3DS-5Ns（fragment）translocated chromosomes;18DM30 is a wheat-L.mollis additional transposition line,contained thirty-eight complete common wheat chromosomes,two complete 6Ns chromosomes,two 3DS-5Ns（fragment）translocated chromosomes and two wheat 3DL-5DL translocated chromosomes;18DM134 is a wheat-L.mollis substitution translocation line,contained thirty-six complete common wheat chromosomes,two complete6 Ns chromosomes,two 3DS-5Ns（fragment）translocated chromosomes and two wheat 3DL-5DL translocated chromosomes.The results of the agronomic trait survey showed that 18DM26,18DM30 and18DM134 have more tillers,longer spike length and higher thousand grain weight,so these three derivative lines can be applied to the genetic improvement of wheat FHB resistance,the creation of new materials and breeding research.3.By comparing the FHB resistance of 18DM30,18DM134 and 18DM291（wheat-L.mollis 6Ns（6D）alien substitution line）,it is hypothesized that the FHB resistance of18DM30 and 18DM134 is derived from 5Ns chromosome;The three Fhb3-linked molecular markers in 18DM30 and 18DM134 did not amplify the same target bands as in Leymus racemosus,suggesting that the Fhb3 genes in 18DM30 and 18DM134 may be different from those in L.racemosus,and that there may be new FHB resistance genes on 5Ns chromosome.