Using ScoT To Analyze The Genetic Diversity Of Different Pod Shattering Characteristics In Common Vetch

Common vetch(Vicia sativa L.)is an important annual,self-pollinating diploid forage legume.Because of its strong environmental adaptability and excellent genetic characteristics,the vetch accessions were widely cultivated throughout the world.However,due to the characteristics of high shattering in most of vetch accessions,a large number of seeds were scattered,resulting in the loss of accession resources,and limiting the promotion of good varieties.At present,no study on genetic diversity of different pod shattering characteristic has been reported.In view of this,we first chose four randomly selected vetch accessions as the research object,and used the SCoT molecular markers to optimize the sampling strategy of the vetch accessions.According to the optimized sampling strategy,the genetic diversity of different pod shattering characteristics in 27 common vetch accessions was studied.It was expected to build a theoretical foundation for the cultivation of non-shattering and high-yielding varieties of vetch accessions.The main results are as follows:1.Using five selected high polymorphic SCoT markers to optimize the sampling strategy of four vetch accessions.By 1,2,3,5,8,10,20,30,40,50 and 60,the total of 11 sampling sizes,the genetic parameters of different sampling sizes are analyzed.The results showed that when the sampling size is 10,the change of the genetic parameters tends to be stable.The cluster results of 10 and 60 these two sampling sizes were the same,and the bootstrap value of these two sampling sizes was similar.Moreover,when the sampling size was 10,it contained more than 90% genetic variation of four vetch accessions.Therefore,taking into account the reserve percentage of genetic variation and the workload,we thought the optimal sampling size for the genetic diversity study of common vetch was 10.2.Based on the optimized sampling strategy,the genetic diversity of 17 non-shattering vetch accessions and 10 shattering vetch accessions were studied using 20 SCoT markers.A total of 478 alleles(Na)were amplified by using 20 SCoT markers,of which 435 were polymorphic,and the Percentage of Polymorphic Loci(PPL)was 91%,which showed high polymorphism.The values of the Expected Heterozygosity(He)and Shannon's Information Index(I)of the non-shattering accessions were 0.96 and 0.66,respectively.And the values of the shattering accessions were 0.89 and 0.61,respectively.The genetic diversity of non-shattering accessions was higher than shattering accessions.In non-shattering accessions,the value of the Fixation idex(FST)was 0.47,and the value of shattering accessions was 0.43.The degree of genetic differentiation of the non-shattering accessions was greater than the shattering accessions.The results of cluster analysis showed that seven shattering accessions were clustered into two independent clusters B and C,respectively.Three shattering accessions and 17 non-shattering accessions were clustered into cluster A,and all accessions had no relationship to their origins.Therefore,there was a certain correlation between the 27 vetch accessions which with different pod shattering characteristics,and it had no relationship with the geographical origins.The result of the hybridization experiment of the vetch accessionss with different pod shattering characteristics indicated that the value of Pod Shattering Mechanical Force(PSMF)of the hybrids was between the values of parent plants.The values of the Seeds Weight per Plant(SWP)and the Dry Weight of Plant(DWP)were all larger than the values of parent plants,showing the advantages of hybrids.