Identification And Application Of Natural And Artificial Chromosome Aberrations In Homoeologous Group 1 Of Triticum Aestivum And Thinopyrum Bessarabicum

Wheat is a globally important crop.Its homoeologous group 1 chromosomes contain quality,yield and resistance genes.In this study,Chinese Spring-Thinopyrum bessarabicum disomic substitution line DS1J(1B),Chinese wheat landraces and synthetic hexaploid wheat lines were used as materials,chromosome variants involving 1J of Thinopyrum bessarabicum were induced,and chromosome composition of synthetic hexaploid wheat F1 plants and Chinese landraces were analyzed in order to reveal the chromosome difference and favorable genes in homoeologous group 1 of wheat and its relatives.The main results are as follows:Firstly,15 chromosome variants involving 1J were obtained by three methods,8 were induced by Chinese Spring ph1b mutant,3 were derived from irradiation-induced M2,and the other four were spontaneous translocations derived from hybrids between DS1J(1B)and Yannong19.Additionally,176 variants were identified in irradiation-induced M1 plants.Based on sequence comparison of homoeologous group 1 chromosomes of wheat and Aegilops tauschii,84 Intron Targeting markers(IT)were developed and 24 were 1 J-specific.Using seven variants involving 1 J,the 24 IT markers together with 31 1J-specific EST-SSR markers previously identified were mapped to six segments of 1J,including 34 on 1JS-1,2 on 1JS-2,12 on 1JL-1,3 on 1JL-2,2 on 1JL-3 and 2 on 1JL-4,respectively.Secondly,47 landraces of China were analyzed and high-resolution karyotypes were developed.In comparison with Chinese Spring,six landraces were identified with five structural variations which included 1DS-4AL-4AS/1DL·ADS-4AL,1DS·4AS/4AL·1DL,2AL·3BL/3BS·2AS,3BL·3AS/3BS·3AL and 3DS·3DL-W.Additionally,total 67 chromosome polymorphisms were observed.Among them,32 were found in A-and 27 in B-genome chromosomes,while only two polymorphisms in 2D were found in D genome,which indicated that most variations occurred in A-genome,followed by B and D genomes in Chinese landraces,the D-genome chromosomes seems showing higher level of conservation.Finally,to broaden the D-genome diversity of Chinese wheat,synthetic hexaploid wheat(SHW)derived from durum wheat and Aegilops tauschii will play important roles.In this study,16 SHW F1 lines were introduced from CIMMYT,and 25 plants of these lines(1-3 plant per line)were identified.The chromosome number varied from 40 to 44,and 15 of the 16 SHW lines were AABBDD and the other one was AAAABB.15 SHW F1 lines involved 14 Aegilops tauschii accessions,where the D-genome chromosomes showed 32 polymorphisms,which were ordered as 2D(6)>1D(5)=4D(5)=6D(5)=7D(5)>3D(3)=5D(3),representing important genetic resources for wheat improvement.