Development Of Synthetic Amphiploids And Selection Of Positive Germplasms

Based on the artificial simulation of wheat origin and evolution process by using tetraploid wheat?Trilicum turgidum L.,2n=28,AABB?hybridized the female parent with Aegilops tauschii?Aegilops tauschii Coss.,2nn=14,DD?parent,then the chromosome doubling process,and finally obtained the synthetic hexaploid wheat,so as to facilitate the introduction of more excellent genes in durum wheat and coarser grass into the common wheat for use,which laid a good foundation for improving wheat quality and increasing wheat yield.Based on the natural doubling gene of durum wheat Langdon the female parent was hybridized with the male parent of different Aegilops tauschii as the male parent.A new synthetic hexaploid wheat was prepared,and the synthetic diploid materials were screened for good characters against FHB and powdery mildew,as well as cytological identification and HMW-GS analysis.The main results are as follows:1.During the synthetic process of hexaploid wheat,56 combinations were found to have successfully obtained triploid hybrid F₁,they were able to bear fruit by self-crossing,but the average self-crossing seed setting rate was also different.Among them,the highest seed setting rate of hybrid combination was 41.86%,and the lowest hybrid combination seed setting rate was 2.78%,which indicated that there was a certain relationship between the inbred seed setting rate of hybrid F₁ and the hybrid combination,and finally,35 new synthetic diploid wheat were obtained in the inbred offspring.2.For observing the number of chromosomes of normal diploid,one of the apical cells of wheat DHSDAU026 was selected to observe the number of chromosomes,and it was found that the number of chromosomes of synthetic wheat DHSDAU026 was the same as that of common wheat,that is,2n=42,which indicated that the hybrid F₁ obtained by the hybridization of durum wheat and Aegilops tauschii had been dyed the phenomenon of natural doubling of chromosomes.3.Through FHB of the resistance of 18 materials to leaf scab in vitro at seedling stage,1 material with medium resistance was selected.In this study,15 diploid materials were identified for the resistance of FHB,and one of them was screened for medium resistance.4.Resistance of powdery mildew E09 small species in seedling stage was identified in46 diploid materials,two high-resistance materials and one medium-resistance material were preliminarily screened.Among them,the identification of their parents Langdon seedling stage showed susceptible,so according to the pedigree speculated that the resistance to powdery mildew in the three resistant materials were all from Aegilops tauschii.5.High molecular weight glutenin fraction was obtained from 20 parts of Aegilops tauschii and hexaploid wheat The results showed that the HMW-GS of durum wheat and Aegilops tauschii were co-dominantly inherited and expressed in the background of synthesis of hexaploid wheat without variation.