Development Of Durum Wheat-Thinopyrum Elongatum Disomic Addition Lines,Substitution Lines And Translocation Lines

Durum wheat(Triticum turgidum L.ssp.durum)is a kind of tetraploid wheat with high gluten content and high protein content.Durum wheat not only has excellent quality,but also has a certain resistance to leaf rust,stripe rust and stem rust.However,durum wheat has poor resistance to Fusarium head blight and root rot.There are abundant resistance genes in the wild relatives of wheat,and quality resistant wheat with exogenous resistance genes can be cultivated through distant hybridization and chromosome engineering.Thinopyrum elongatum is a wild relative of wheat,and it has many excellent properties of resistance to Fusarium head blight,powdery mildew,root rot and other wheat diseases.The establishment of alien addition lines,substitution lines and translocation lines through distant hybridization between wheat and Th.elongatum is a good way to exploit the superior genes of Th.elongatum.A complete set of common wheat-Th.elongatum addition lines and substitution lines have been developed,and a complete set of durum wheat-Th.elongatum addition lines and substitution lines have not yet been developed.Only durum wheat-Th.elongatum 1E addition line and substitution lines have been developed,and the durum wheat-Th.elongatum 7E addition line has been developed in our laboratory,which 7E chromosome derived from the tetraploid Th.elongatum.However,the chromosomal composition and FISH karyotype of the tetraploid Th.elongatum is still not clear.The aim of this study is to analyze the chromosomal composition of tetraploid Th.elongatum,and make the FISH karyotype of 8801 and tetraploid Th.elongatum.In addition,the assay methods including specific molecular markers of Th.elongatum,chromosome counting,genomic in situ hybridization(GISH),and non-denaturing fluorescence in situ hybridization(ND-FISH)were used to identify the chromosome constitution of the hybrid offspring population between durum wheat Langdon(AABB)and allohexaploid wheat line 8801(AABBEE)in the present study.Some chromosome addition lines,substitution lines,and translocation lines were established,and their agronomic traits were investigated.The main results of the study are as follows:1.The 45 S rDNA loci of diploid and tetraploid Th.elongatum were analyzed.The result showed that the diploid Th.elongatum had two pairs of 45 S rDNA loci,which were located at subtelomeric region of the short arm on 5E chromosome and secondary constriction of 6E chromosome,respectively.The relative positions of 45S rDNA loci on the tetraploid E chromosome were same as diploid,and the number were twice that of diploid.The result suggests that the tetraploid Th.elongatum is likely to be doubled from diploid species in nature.2.The FISH karyotype of 8801 and tetraploid Th.elongatum were set up by using repetitive sequence pSc119.2 and pAs1,this FISH karyotype can be used to identify tetraploid E chromosome in the background of durum wheat.Simultaneously the chromosomes characterization of tetraploid Th.elongatum was analyzed according to the similarities and differences distribution of pSc119.2,pAs1,and pTa71 in the chromosome of diploid Th.elongatum,tetraploid Th.elongatum,and allohexaploid wheat line 8801.We finally inferred tetraploid Th.elongatum may be a autotetraploid.3.Durum wheat-Th.elongatum 3E and 6E disomic addition lines,1E(1B)disomic substitution line and 1AS-1EL disomic translocation line were identified in this study.Molecular markers identification of four lines were implemented in three consecutive years.The results showed that these lines were stable genetic materials.4.The plant height of four stable lines was significantly lower than their parent Langdon.The area of flag leaf was significantly higher than their parent Langdon.In addition,The length of spike,seeds per spikelet(fertility)and kernels per spike were improved in line Du-DA6E.It was speculated that the chromosome 6E may contain genes for increasing yield related traits to yield improvement.