Exploration Of SSR Loci Associated With Mainly Economic Traits And Analysis Of Expression In Armeniaca Sibirica

The Armeniaca sibirica is an important ecological and economic tree species.But the"bottleneck"restricting the development of the industry is the yield of fruit is low and unstable.Therefore,breeding of its fine varieties has becoming a top priority.In this paper,association analysis between main economic traits of 32 Armeniaca sibirica clones and SSR markers was studied.The phenotypic effects of alleles were also studied.On this basis,expression of elite alleles was analyzed.The summarized results were as follows.(1)155 pairs of primers with clear bands are screened from 600 pairs of SSR primers for association analysis.The average number of alleles(N_A)and average number of effective alleles(N_E)of 155 loci were 5.858 and 3.412 respectively.Average number of PIC was 0.622,which show that 155 loci were highly polymorphic.The genetic similarity coefficients among32 clones ranged from 0.620 to 0.907,with an average number of 0.731.The result showed that genetic difference between 32 clones was small and the genetic relationship was near.(2)Results of Structure software showed that 32 Armeniaca sibirica clones could be divided into 3 categories.49 SSR loci associated to 13 economic traits were preliminarily obtained through association analysis in the statistical sense.Among them,one trait could be associated with multiple loci,which had 12 such traits.The results showed that the trait was controlled by multiple gene loci.In addition,one loci could also be associated with multiple traits.There were 22 groups of cases.The results showed that these loci were in linkage inheritance.(3)Phenotypic effects of 49 SSR association loci were analyzed.The results found the alleles with highest phenotypic effects of synergistic and deficient effects on the 13 economic traits of Armeniaca sibirica.Typical materials with elite alleles of fruit yield were clone 1,clone 28 and clone 39.Typical material of fruit was clone 81.Typical material of kernel was clone 43.Typical material of almond was clone 21.(4)19 association loci were screened by BLAST and PCR amplification.18SrRNA was selected as the best reference gene for real-time PCR of Armeniaca sibirica clones from 4reference genes.Real-time PCR reaction procedure was modified from the original two-step reaction to a three-step reaction.(5)The results showed that gene expression of 19 association loci could be divided into 3types during the ripening of fruit by analysis of expression.The first type showed an upward trend,the second type showed a downward trend,while the third type had no regularity.The variation of gene expression in the association loci was different in fruit,kernel and almond of different clones.There were different loci with positive correlation,negative correlation and insignificant correlation in fruit,kernel and almond of different clones.For 3 clones,genes of association loci were detected in fruit,kernel and almond at the same time,in which X72 was detected in fruit,kernel and almond of the 3 clones.This paper initially screened 19 loci associated with fruit,kernel and almond,which laid a foundation for further research in this field.It also provided a scientific reference for molecular marker-assisted breeding of this tree species.