The Production Of Synthetic Hexaptoid Wheat Between Triticum Turgidum And Aegilops Tauschii And The Analysis For Their Agronomic Traits

Common wheat (Triticum aestivum L.,2n=6x=42,AABBDD) is a good example ofallopolyploid including three diploid genomes A, B and D. By the mimic of common wheatorigination，many synthetic hexaploid wheats have been produeed by the intercrossingbetween T. turgidum L(2n=4x=28,AABB)(maternal) and Ae. Tauschii (2n=2x=14, DD),followed by chromosome doubling. It is convenient to transfer the excellent genes to thecommon wheat from the T. turgidum L or Ae. tauschii using the synthetic hexaploid wheats asa bridge parent.The triple hybrids were obtained from six cross combinations between Triticum turgidumand Aegilops tauschii. These hybrid produced selfed seeds，with the highest seed-setting of8.45%，and the least of0.10%. These results indicated these hybrids were partial fertile.However, the fertility was related to their crosses. The new synthetic wheats were obtainedfrom the selfed hybrids.All of these S1plants for synthesized hexaploid wheats observed were found to have2n=42chromosomes，suggesting that they were amphidiploids that were spontaneouslyproduced via a union of unreduced gametes.The average univalents varied from1.78-6.32in different synthetic hexaploid wheats.The average value of univalents in Syn-sdau-4was1.78，and the bivalents was20.11, whichindicated that Syn-sdau-4was stable in cytology. This made it desirable for populationconstruction for genetic analysis.These synthetic hexaploid wheats showed high plant，strong tiller ability，long spike，and low1000-seed-weight. Plant height, tiller number, and1000-seed-weight showedsignificant differences among synthetic hexaploid wheats. Furthermore，the Ae.tauschii genotypes may attribute the variation of plant height, spike length, tiller number and1000-seed-weight in synthetic hexaploid wheat background with same T. turgidum genotype.