| As the most cultivar of eggplant(Aubergine, Brinjal), Solanum melongena L. has been grown widely in Asia, South central Europe and Miditerranean. Although its production and output value are both lying in top 10 compared to the other kinds of vegetable worldwide, the research level of the genetic and breeding in eggplant hardly match its playing the important role in vegetable production all over the world, which severly limited the development of its production and quality of its harvested product.The main reasons involved in the above problems are as follows : firstly, the narrow genetic background of the eggplant cultivars directly impedes the progress of genetic research and breeding practice. Secondly, the tools of study on the quantitative trait genetics has still located in the tradional methods. Thirdly, thedevelopment of the helpful markers and genes associated with major economical chacracters lagged behind.These problems reflected in genetic and breeding research are as below, the germplasm resourceshad lowly diverse origin of geography, the limited number of molecular markers, insufficient markers density of genetic linkage map, the less gene with which the molecular markers had close associated with important economical charaters, are available for marker-assisted selection and genomic selection. Aiming at the problems above, the present paper had a study on the the genetic diversity, association analysis in eggplant from 33 countries belong to 5 continents with SSR and SRAP markers and morphological traits. Meanwhile, we executed the develpment of new type molecular markers with high polymorphism by SLAF-seq which based on Reduced-Representation Genomic Sequencing in two parents with difference in several traits and their F2 population, then implemented the construction of high density genetic linkage map and location of QTL for certain traits.The main result as follows:1. A total of 133 eggplants and its related species accessions were collected for analysis of genetic diversity by 27 morphological traits, the result indicated that the experimental materials had a large number of morphological varitions, the total mean of H’ and J were 2.110 and 0.753, respectively.Among the traits concerned closely breeding, the index of fruit, fruit length, fruit color, fruit color under calyx and the fruit shape had a larger coefficient of variation(CV). Leaf thorn, calyx prickel and jugum had the highest CV, thus they can act as thecriteria of taxon.On the basic of the result from the factor analysis, the test materials could be clustered well-defined into 7 groups, namely GⅠ-GⅦ,GⅠconsisted of 4 sub-groups, sub G1-sub G4。2. Analysis of genetic diversity for 133 accessions with 5 SSR and 25 SRAP revealed a lower genetic diversity in molecular markers. Percentage of polymorphic bands producted by primers was 99.24%, polymorphism information content( PIC)per locus was ranged from 0.015-0.500, with a mean of 0.312. Effective number of alleles per locus was 1.5114 on an average, ranged from 1.2905-1.7459. Nei’s gene diversity index per locus varied from 0.1701-0.4056,with an average of 0.2992. Shannon Informaton index per locus was 0.4550 on an average, ranged from 0.02661-0.5855. Similarity was a mean of 0.764, with a range from 0.024-0.968. The test materials were clustered into 6 groups by the molecular markers with a greater PIC value than 0.25.The similarity between S.melongenaand S.dasyphyllum、S.integrifolium、S.aethiopicum、S.macrocarpen、S.viarum, S.anguiviwas0.837、0.828、0.822、0.767、0.589 and 0.541, respectively.3. The software of Structure2.3.4 and Tassel3.0 were used for the analysis of population structure and association analysis for the data matrix of molecular markers consisted of 0 and 1.All accessions were grouped into 3 subpopulations of A1, A2 and A3 by Structure.The proportion of individuals with Q>0.6 each subpopulation was respectively 89.66%,91.30% and 70.69%, which implied the individuals from each subpopulation retained ratively a single kinship. Especially, the genetic basis of A1 and A2 was a little poor.With the analysis of association mapping by Tassel, 28 loci were associated with 14 traits at the standard of R2>0.05 ' P<0.001, Of which, 4 loci GA34SA11-2(R2>0.1)and OD3SA16-5, GA34SA11-4(R2>0.1), FC8ME7-3(R2>0.1)were correlated highly with diameter of corolla, plant architecture and style length at the level of P<10-4, respectively.In addtion, 9 traits had two loci associated with themselves.4. Development and identification of new type molecular markers by SLAF-seq based on Reduced-Representation Genomic Deep Sequencing in eggplant with two inbred lines 609 and 749, and between which an intraspecific F2 population derived from a cross.A library consists of 120,925 SLAF tags was constructed at the standard of sequencing depth of parents and offspring with an mean of 24.40× and 4.09×,respectively. Out of which, 6883 polymorphic SLAF tags were acquired. Taking Arabidopsis thaliana ecotype Columbia as control, give the course of experiment about sequencing DNA and constructing SLAF library a supervisory control of accuracy and effectiveness according to the result from the same test program for control.Acquired 79.19% of efficiency of alignment with reference genome by Paired-end mapped reads, and digestion efficiency with 96.74%. Most of insert sizeare ranged from 414bp-464 bp. Coding two parents and their offspring by the 2 alleles, 5543, 4.38% of library, polymorphic SLAF with genotype aa×bbwere screened.5. 1782 SLAF tagswith polymorphism, of 5543, were designated as Markers forconstructing genetic map, in term of sequencing depth, the number of SNP and homozygosity of parents genotype. Caculated the genetic distance of Markers and made Markers permutation whin each linkage group, then constructed a high density genetic linkage map named NHE2015, with 12 linkage groups, total coverage of 1,454.63 c M,average distance of 0.82 c M and max gap 5.42 c M. Sequencing depth of Markers was 32.73× on an average, that of parental and maternal genotype were respectively49.72× and 42.32×, and that of offspring was 6.17×. The source of hplotype from all materials in population are relatively identity. The diagnal of map concerned the reconbination relationship between paired markers appeared on a clearly yellow line. All result above demonstrated the genetic linkage map acquired by the present study is reliable and available for subsequent research, such as molecular markers selection and QTL location etc.6. A total of 9 QTLs were detected by CIM, of which 6 QTLs were statistically significant correlation with fruit index, named fs8.1、fs11.1、fs11.2、fs11.3、fs11.4 and fs11.5, respectively. Those all located between Marker1404739-Marker14859 with a distance of 5.0c M on linkage group 11,QTL was ranged from 1.0-2.4c M. All of them could explained 20% above of the variation for fruit index as major QTLs. fs8.1 were mapped to linkage group 8 and between Marker565746-Marker1200185 with a interval of 3.2c M. As a minor QTL, it could explained 7.26% of variation for fruit index.The fruit color under caylx was controlled by cuc6.1、cuc6.2 and cuc6.3, major QTLs with an explanation of greater than 10% of variation for the fruit color under caylx, between Marker1661695-Marker591764 in linkage group 6, QTL was ranged from 1.1-3.0c M. |
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