Screening And Identification Of EMS Induced Mutants On Flowering Habit In Wheat

The utilization of heterosis can significantly increase wheat yield,and the creation of hybrid parents is one of the limiting factors of current hybrid wheat applications.Wheat hybrid seed breeding requires the breeding of parents with good agronomic traits and flowering habits,and the preferred hybrid combinations.EMS mutagenesis is mostly high-density allele point mutation,and mutants with stable traits are obtained after multiple generations,which can be used as a way for parental creation in hybrid wheat.In this study,common wheat Shannong 22（SN22）,Shannong 23（SN23）,Shannong 24（SN24）,Shannong 36（SN36）,Shannong 055525（SN055525）and Shannong identification 30（SNJD30）were used as materials.Through EMS induction treatment,（1）In the first generation population（M₁）of mutagenesis,the six variation types of plant height,tiller,leaf color,flowering period,flowering habit and fertility were investigated to find mutant materials.（2）In the second generation population（M₂）,the above 6 types of variants were investigated,and the excellent materials with stable inheritance were further screened to obtain the mutation materials of flowering-related traits.（3）The genetic variation of SSR loci was analyzed for the mutant materials of flowering habit and research characteristics of flowering-related traits.The results of the study are as follows:1.In the M₁generation,the field investigation found that most of the mutagenized plants showed a decrease in plant height,and the mutation rate was above 80%;703 oligo-tiller mutants were mutated,and the mutation rate was 3.45%～10.16%;among the leaf color mutation types,the mutation rate of leaf color yellow-green（119 plants）was 0.95%～2.16%,and the leaf color is dark green（33 plants）was 0.15%～0.56%;176 mutant plants at flowering stage,the mutation rate of flowering period extension was 0.45%～2.10%,the early mutation rate at flowering stage was 0.53%～2.40%;among the variation types of flowering habit,it was found that 605 plants showed the characters of increased flowering angle,exposed stigma,exposed anther and enlarged anthers;326 plants of male sterility mutant type,the mutation rate was 1.85%～5.60%.2.The M₂generation population includes the mixed harvest planting population of mutagenized strains and the panicle row population.（1）In the mixed planting population,a total of 914 plants showed the above phenotypic mutations,and the total population mutation rate was 12.03%.Including 180 mutants of plant height,138 mutants of tillering,79 mutants of leaf color,145 mutants of flowering stage,296 mutants of flowering habit,and 76 mutants of sterility,the mutation rates of different mutation types were 2.37%,1.82%,1.04%,1.91%,3.89%and 1.00%.（2）The row population was made of 1735 mutant single ears.Except for fertility mutations,all phenotypes had varying degrees of recovery.The recovery rate was51.30%,which showed the greatest degree of recovery and the recovery rate was81.11%～93.75%.Compared with the characteristics of mutagenesis parents,among 845 spike lines with stable mutations,14 spike lines with excellent phenotypes in plant height,tiller and flowering habits,which can be used in hybrid wheat seed production,among which 5 mutant spike lines（ESN23AN-5,ESN36GO-14,ESN36GO-23,ESN055525AN-7,ESNJD30AN-6）performed well in flowering habits.3.The obtained five mutant panicle lines showing flowering-related traits and their corresponding mutagenized parents were used as materials.（1）The mutation authenticity of the five mutant panic lines obtained was identified,and the SSR genetic variation characteristics were analyzed.To 9～16 cg-WSSR loci variation,the average variation rate was 12.13%.（2）The characteristics of flower organ mutation were analyzed.The results showed that compared with the corresponding parental control,the anther length and pollen amount of the five mutant materials increased by 4.68%～12.50%and 3.76%～19.72%.ESNJD30AN-6 showed a 22.73%increase in pollen tube germination rate,and the expression levels of genes related to starch synthesis and transport in wheat were significantly increased in most mutants.To sum up,5 mutant materials with excellent flowering habit that can be used as hybrid parents were obtained in this study,all of which had true mutations,and showed improvement effects on the parent materials in the expression of flower organs and starch synthesis transport genes.This study enriched the genetic diversity of hybrid parents and provided a material basis for the utilization of hybrid wheat.