| Seedless grapes are favored by consumers for their convenient in fresh consumption.A few studies have been done on the formation of seedless grapes,but the genetic mechanism underlying seedlessness in grape is still obscure.In this paper,generality of reported SSR molecular marker was verified on 90 table grape varieties by using four seedless related SSR molecular markers,including P1_Vv AGLL11,P2_Vv AGLL11,P3_Vv AGLL11 and VMC7F2,which have been proved to link with seedlessness in grape.The goal is to find molecular markers with high generality in the detection of seedless traits,which further assists breeding of seedless varieties and improves breeding efficiency in grape.Ethylene plays an important role in regulating fruit ripening and peduncle browning during storage.In order to understand ethylene production pattern of grape fruit and peduncle,and identify the excellent allelic variation related to ethylene emission traits of grape fruit and peduncle,62 natural populations of grape varieties were used as experimental materials,and a total of 79 pairs of SSR primers were used to analyze the natural population by using genome-wide association analysis(GWAS)to find molecular markers related to ethylene production in grapes.The main results of this study are as follows:1.Verification of four SSR molecular markers revealed that there was no polymorphism in the 62 natural population by using VMC7F2 primers.Stable polymorphic sites were amplified by using P1_Vv AGLL11,P2_Vv AGLL11,and P3_Vv AGLL11 markers.Genetic diversity analysis found that Na,Ne,and PIC ranged from 2 to 3,1.8132 to 1.9446,and 0.37 to 0.49,respectively.The minimum PIC index of P3_Vv AGLL11 is 0.37,and Na minimum is 2.Moreover,it was found that amplification results of p3_Vv AGLL11 primers had the highest frequency of the heterozygous genotype ab(56.86%)in the seedless varieties,and the highest frequency of the genotype BB in the varieties with seed was 66.67%.Only two genotypes,A/a and B/b,were found in the p3_Vv AGLL11 results with the two traits.From the above analysis,it was proved that p3_Vv AGLL11 had the best verification effect on grape seedless traits in this validation.2.After analysis of population structure,62 grape varieties can be devided into two subgroups,V.vinifera and V.vinifera×V.Labrusca,which was consistent with the origin of cultivars.Linkage disequilibrium(LD)analysis was conducted after removing the interference from population subpopulations.A total of 3,081 site combinations were generated for 79 SSR loci in 19 linkage groups,in which 2584 were effective combinations,including 308 loci(D'? 0.5)with a relatively high LD,accounting for 12% of the effective combination loci.In all combinations,66 paired loci supported by statistical probability(P?0.01)were obtained,accounting for 3% combination loci.Among them,VVIN33 in the 5th linkage group and SCU14 in the 16 th linkage group had higher linkage disequilibrium with other linkage group sites.3.General linear model(GLM)and the mixed linear model(MLM)were used for correlation analysis,and two graphs QQplot and Q+Kplot were made by the two models.A certain correlation was found between the fruit ethylene production(F-ETH)or the peduncle ethylene production(P-ETH)and the tested SSR primers.Anaylysis of the Manhattan chart under the MLM model indicated that three primers,VVIN70,VVIN83 and VMC9F4 have a high correlation with the ethylene production of fruits in this association analysis.4.Sequencing analysis of the targeted fragment amplified by VVIN70 primers revealed that it was located in the promoter region of the ethylene response transcription factor RAP,and there were deletion mutations in the amplified fragments in different varieties. |
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