The Mutantion Of Wheat Induced By EMS And Identification And Screening Of Excellent Mutants

At present,the lack of high-quality germplasm is the most serious problem in wheat breeding.New germplasm with high quality,disease resistance,high and stable yield can be cultivated by artificial induced mutation to improve the current situation rapidly and effectively.In the present study,different combinations were set up,and EMS?Ethyl methyl sulfone?was used to induce mutations in four wheat varieties,Xi Nong 99,Xi Nong 979,Xi Nong 977,and Xiao Yan 22,respectively.The most suitable treatment for each variety was determined.At the same time,the optimal treatment of each variety was used to explore the differences in the sensitivity of different wheat varieties to EMS mutagen.Through the phenotypic identification of agronomic traits and results of SSRs molecular marker detection,all kinds of mutations in the mutagenic population were screened and identified,and the mutant populations with stable genetic traits were constructed.The results of the experiment are as follows:1. A total of 15 different combinations with five concentrations?0%,0.8%,1.0%,1.2%,1.4%?and three time-gradients?8h,10h,12h?were set up to treat four wheat varieties.The root and bud length of different wheat varieties were significantly?p<0.05?different under various mutagenic conditions,and the sensitivity of roots was stronger than that of buds.The combinations with high concentration and longer time had a strong toxic effect on the germination and vitality of wheat,which inhibited the growth and development of seeds and even led to death.According to the absolute germination rate,and combined with the damage degree of each treatment combinations,the optimal mutagenic combinations of Xi Nong 99,Xi Nong 979,Xi Nong 977,and Xiao Yan 22were determined to be 8h+1.2%,12h+0.8%,12h+1.0%,and 12h+1.0%,respectively.2. The seeds of Xi Nong 99,Xi Nong 979,Xi Nong 977,and Xiao Yan 22 were treated with EMS at the different and optimal concentration of mutagenics.The results showed that there was no significant?p<0.05?difference in the sensitivity of the four varieties to their optimal treatments.The mutation rates of the four varieties in M₁generation were 13.63%,7.83%,9.26%,and 11.86%,respectively.The highest mutation rate was Xi Nong 99 with 13.63%,and the lowest was Xi Nong 979 with 7.83%.The phenotypic change rate of M₁ was significantly different among varieties,but the main types were in stem,spike and leaf.3. Based on the statistical analysis of M₃ generation mutant populations of the fourvarieties,173,42,31,and 39 mutant materials were obtained,and the total mutation rates were 7.28%,6.71%,7.18%,and 8.26%,respectively.Six types of mutations including spike,leaf,stem,plant type,growth period and fertility were obtained.A total of 285 M₃ mutant materials were obtained from the four varieties after generation separation and stabilization.The mutation rates of the M₃ generations of the four varieties are not significantly different and the traits can be stably inherited.4. SSR primers?42 pairs?were selected to detect 285 M₃ generation mutant materials.The results showed that the differential markers between 23 mutants and their parents were greater than 3.A total of 262 mutant materials were obtained from the four varieties through phenotypic screening and molecular marker identification.The direction of mutation population of the four varieties was aimless,most of them were reverse mutations,and few of them could be used directly.Compared with the parents,the mutation materials had DNA level variation.SSR markers were used to detect the variation of some locis,the amplified fragments showed polymorphism,and new fragments were produced.