Cytogenetic Characterization And Molecular Marker Development Of A Wheat-lophopyrum Scirpeum 3E/3D Substitution Line

Wheat is a worldwide cultivated staple cereal that feeds around 40% of population.In modern wheat breeding,however,the genetic diversity and resistance to biotic as well as abiotic stresses of common wheat are decreasing,restricting further improvement of wheat yield and quality.Wheat related species express a large number of favorable genes/alleles that could be genetically transferred into elite cultivars for diversification of the gene pool and improvement of wheat.Lophopyrum scirpeum,a wheat-related species and belonging to Lophopyrum,Triticeae of Gramineae,which is characterized by its vigorous growth,highly productive,and resistant to a spectrum of biotic(FHB,rust,powdery mildew,and yellow dwarf)as well as abiotic stresses(cold,drought,and salt).It is served as an important genetic resource in wheat improvement.In the present study,a wheat-Lophopyrum scirpeum chromosome substitution line K17-1078-3 was generated by crossing and backcrossing donor parent amphidiploid 8801(2n = 6x = 42,AABBEE)with Sichuan elite wheat cultivars.The genomic in situ hybridization(GISH)and fluorescence in situ hybridization(FISH)were employed to characterize the chromosomal composition of K17-1078-3.The resistances to stripe rust and powdery mildew and several agronomic traits were evaluated for the substitution line.Moreover,genotyping by sequencing(GBS)was applied to obtained lines for developing molecular markers.The main findings are as follows:1.The GISH and FISH were employed for the characterization of chromosome composition,showing that K17-1078-3 consists of 42 chromosomes and was a 3E/3D substitution line.2.Further evaluation on the resistances to stripe rust and powdery mildew in parental lines and K17-1078-3 showed that common wheat parents Chuannong 16 and Zhengmai 9023 were highly susceptible,whereas 8801 and K17-1078-3 were highly resistant to stripe rust and powdery mildew.3.Compared with its parental common wheat,K17-1078-3 expressed similar plant height,spike length,spikelet number and kernel weight.4.GBS was applied to Lophopyrum elongatum,Lophopyrum scirpeum,amphidiploid 8801,and common wheat-Lophopyrum scirpeum 1E-7E chromosome substitution lines.It produced 269 specific sequences,of which 146 were specific to3 E chromosome.Furthermore,a total of 49 pairs of specific and stable 3E chromosome molecular markers were verified across wheat-related species.