Molecular Cytogenetic Identification Of Wheat-thinopyrum Intermedium Derived Lines ES-13,ES-14 And ES-24

The wild relatives of Triticeae species are diverse and carry large numbers of superior genes,which are a rich genetic resource pool for the genetic improvement of cultivated wheat.The transfer of superior genes from closely related species into wheat is an important means to create new types of wheat variation and broaden the genetic basis of wheat.Thinopyrum intermedium(Host)Barkworth and D.R.Dewey(2n = 6x = 42),which is highly resistant to wheat diseases such as powdery mildew,stripe rust,leaf rust,culm rust,yellow dwarf,provided beneficial genes for wheat breeding.Through distant crosses and chromosome engineering techniques,superior genes from Th.intermedium can be introduced into common wheat varieties,providing a large number of superior genes for wheat germplasm innovation and variety improvement.In this study,a comprehensive molecular cytogenetic characterisation of three common wheat-Th.intermedium derived lines ES-13,ES-14 and ES-24 was carried out by cytology,in situ hybridisation,molecular marker techniques,morphological investigations and stripe rust resistance analysis.The main findings were as follows.Molecular cytogenetic identification of common wheat-Th.intermedium disomic addition line ES-24Wheat-Th.intermedium alien disomic addition line ES-24 derived from a cross between the Th.intermedium and the wheat Abbondanza nullisomic lines.Line ES-24 were characterized by a cytogenetic analysis,a sequential fluorescence in situ hybridization(FISH)–genomic in situ hybridization(GISH),an analysis of functional molecular markers and disease resistance.The cytogenetic results suggested that ES-24 contained 44 chromosomes.The configuration of chromosome I in metaphase meiosis is 2n=22Ⅱ,and can be equally segregated in anaphase meiosis,indicating that it can be inherited stably.The results of in situ hybridization showed that ES-24 contained 42 common wheat chromosomes and a pair of St chromosomes from the Th.intermedium.EST and PLUG molecular marker molecules indicated that the foreign chromosome belonged to the 7St chromosome of the Th.intermedium.Fluorescence in situ hybridization analysis showed that there were 42 chromosomes consistent with the Chinese Spring standard karyotype in ES-24,and the 7St chromosome karyotype was obtained.In addition,ES-24 showed high resistance to stripe rust in both the seedling and mature stages.Therefore,the highly disease-resistant common wheat-Th.intermedium derived offspring ES-24 can be used as a potential intermediate material in wheat disease-resistant breeding and variety improvement.Molecular cytogenetic identification of common wheat-Th.intermedium disomic substitution line ES-14Line ES-14 derived from a cross between the Th.intermedium and the wheat Abbondanza nullisomic lines.The cytological observation showed that ES-14 contained 42 chromosomes and that its chromosome I in metaphase meiosis configuration was 2n=21 II,and that it can segregate equally in anaphase meiosis I.The genetic properties are stable.In situ hybridization analysis revealed that ES-14 carrieed 2 St chromosomes but lacked 3D chromosomes.The EST and PLUG molecular marker molecules further verified that the exogenous chromosome belonged to chromosome 3St of Th.intermedium.In terms of agronomic traits,ES-14 did not differ significantly from its parent Abbondanza nullisomic lines terms of spike shape,spikelet number and awning,but plant height was significantly lower than that of both parents.Resistance to stripe rust was identified and ES-14 showed high resistance to stripe rust at maturity.The above results indicated that ES-14 was a common wheat-Th.Intermedium 3St(3D)substitute line with high resistance to stripe rust and can be used as intermediate material in wheat disease resistance breeding and variety improvement.Molecular cytogenetic identification of common wheat-Th.intermedium addition-substitution line ES-13Line ES-13 derived from a cross between the Th.intermedium and the wheat Abbondanza nullisomic lines.The cytological results showed that ES-13 had 44 chromosomes and its mid-meiotic I chromosome configuration was 2n=22 II,and it could segregate equally in late meiosis I,indicating that it could be inherited stably.In situ hybridization results showed that ES-13 contained 40 common wheat chromosomes and lacked the 3D chromosome group,but carried four Th.intermedium chromosomes,and combined with the results of EST and PLUG molecular marker molecular analysis,the two exogenous chromosomes carried by ES-13 were identified as one pair of Th.intermedium3 St chromosomes and the other pair of Th.intermedium 5St chromosomes.ES-13 did not differ significantly from the parental Abbondanza in spike shape,spikelet number and awning,but is shorter than both parents,has slightly longer spikes than the parent Able and has smaller,darker brown seeds.Resistance to stripe rust was identified and ES-13 showed high resistance to stripe rust at both seedling and maturity stages.The identification of resistance to stripe rust showed that ES-13 showed high resistance to stripe rust at both seedling and maturity stages.The above results indicate that ES-13 is a common wheat-intermediate creeping wheatgrass 3 St(3D)-5St heterozygous substitution line with high resistance to stripe rust and can be used as a potential intermediate material in wheat breeding for disease resistance.