Genetic recombination produces new allelic combinations,thereby introducing variation for domestica-tion.Allopolyploidization has increased the evolutionary potential of hexaploid common wheat by con-ferring the advantages of heterosis and gene redundancy,but whether a relationship exists between allopolyploidization and genetic recombination is currently unknown.To study the impact of allopoly-ploidization on genetic recombination in the ancestral D genome of wheat,we generated new synthetic hexaploid wheats by crossing tetraploid Triticum turgidum with multiple diploid Aegilops tauschii acces-sions,with subsequent chromosome doubling,to simulate the evolutionary hexaploidization process.Using the DArT-Seq approach,we determined the genotypes of two new synthetic hexaploid wheats with their parents,F2 plants in a diploid population(2x,D1D1×D2D2)and its new synthetic hexaploid wheat-derived population(6x,AABBD1D1×AABBD2D2)).About 11％of detected SNP loci spanning the D genome of Ae.tauschii were eliminated after allohexaploidization,and the degree of segregation distortion was increased in their hexaploid offspring from the F2 generation.Based on codominant genotypes,the mean genetic interval length and recombination frequency between pairs of adjacent and linked SNPs on D gen-ome of the hexaploid F2 population were 2.3 fold greater than those in the diploid F2 population,and the recombination frequency of Ae.tauschii was increased by their hexaploidization with T.turgidum.In con-clusion,allopolyploidization increases genetic recombination of the ancestral diploid D genome of wheat,and DNA elimination and increased segregation distortion also occur after allopolyploidization.Increased genetic recombination could have produced more new allelic combinations subject to natural or artificial selection,helping wheat to spread rapidly to become a major global crop and thereby accelerating the evolution of wheat via hexaploidization.

Crop Research Institute,Sichuan Academy of Agricultural Sciences,Chengdu 610066,Sichuan,China;Key Laboratory of Wheat Biology and Genetic Improvement on Southwestern China,Ministry of Agriculture and Rural Affairs,Chengdu 610066,Sichuan,China;The Applied Plant Genomics Lab,College of Agricultural Sciences,Nanjing Agricultural University,Nanjing 210095,Jiangsu,China;Triticeae Research Institute,Sichuan Agricultural University,Chengdu 611130,Sichuan,China

[1]Hongshen Wan;Jun Li;Shengwei Ma;Fan Yang;Liang Chai;Zehou Liu;Qin Wang;Zongjun Pu;Wuyun Yang-.Allopolyploidization increases genetic recombination in the ancestral diploid D genome during wheat evolution)[J].作物学报（英文版）,2022(03):743-753

Allopolyploidization,allopoly,ploidization,turgidum,hexaploidization,DArT,D1D1,D2D2,AABBD1D1,AABBD2D2,allohexaploidization,codominant

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