Production Of Substitution Lines Between Chromosomes Of Aegilops Variabilis And D Genome Of Wheat

Tetraploid wheat（Triticum turgidum）is very similar with common wheat（T.aestivum）morphologically,and have similar or higher yield potential than latter.However,common wheat is able to be processed into more types of food and owns better environmental adaptability than tetraploid wheat because of the contribution of D genome.By the benefit of these traits,common wheat quickly replaced tetraploid wheat and become the main cultivated wheat worldwide,accounting for more than 95%wheat production.Introducing alien genes into D genome of cultivated common wheat may achieve the double effect of enriching the genetic diversity of common wheat without yield penalty.Substitution lines（monosomic or disomic）are important intermediate materials in chromosome engineering of using ph1b mutant inducing homoeologous recombination and thus introducing alien genes.Aegilops variabilis（UUS^vS^v）is an important gene source for genetic improvement of wheat,which is rich in resistance to diseases,pests and high content of trace elements.In this study,crosses between T.turgidum-Ae.variabilis amphidiploids（AABBUUS^vS^v）and common wheat were made to create substitution lines between chromosomes of U/S^vand D genome.These substitution lines laid material foundation for the production of the corresponding translocations.The main results are as follows:1.The progeny of T.turgidum-Ae.variabilis amphidiploids（AABBUUS^vS^v）gradually lost chromosomes of U/S^vgenome after multiple rounds of crossing and backcrossing with common wheat followed by self-pollination.In F₁hybrids,a complete set of D,U and S^vgenome chromosomes existed in single copy.In BC₁F₁generation,each homologous group of D,U and S^vgenome consisted of 2.5 chromosomes in average（with variation range of 1-4）including 1.5 D genome chromosomes,0.4 U genome chromosomes and 0.5 S^vgenome chromosomes.2.A total of six BC₁F₂,28 BC₂F₁and three BC₂F₂plants were screened by GISH and FISH.A total of 19 substitution lines of U/S^vand D genome were obtained including 18monosomic substitution lines and one disomic substitution line.Substitution lines involved in one plant of 1U/1D,one plant of 1U+1S^vfor 1D,three plants of 2U/2D,two plants of2S^v/2D,one plant of 2U+2S^vfor 2D,two plants of 3U+3S^vfor 3D,one plant of 3U/3D,one plant of 4U/4D,one plant of 5U/5D,one plant of 5S^v/5D,two plants of 6U/6D,two plants of 6S^v/6D,two plants of 7U/7D,seven plants of 7S^v/7D.These substitution lines lay a material foundation for the directed production of translocation lines between homoeologous pairs of U/S^vand D.3.Homoeologous recombination occurred in BC₂F₁and BC₁F₂population.Among them,17 plants carrying recombinant chromosomes were detected,and six of them occurred between D and U/S^vgenome.The chromosome configurations of them were5DS-5DL.7UL,7DS.7UL,5BS.5BL-U/S^v,5BS.U/S^v,D.6UL and U/S^v.6DL.In addition,eight types of translocation chromosomes with recombination happened between other genome chromosomes were obtained.Their chromosome configurations were2BS.2BL-2S^vL,2S^vS-2BS.2BL,3S^vS-3BS.3BL,4S^vS-4BS.4BL,6DS.6DL-6AL,7AS.7AL-7DL,recombination of wheat chromosome with 2S^vL,and at the ends of the short arms of the alien chromosome.