| Introgression lines(ILs)are a group of strains that differ only in some chromosome segments and have the same genetic background.They can be used to improve the problems of narrow genetic background and reduce genetic diversity caused by long-term domestication.Gooseberry tomato(S.pimpinellifolium)is a wild tomato species,which retains a lot of excellent genes,and is one of the wild tomato species with the closest relationship with ordinary cultivated tomatoes.It can be directly crossed with ordinary cultivated tomatoes to achieve the purpose of rapid traits transformation.In this study,the excellent cultivated tomato ’Jina’(S.lycopersicum)was used as the recipient parent,and the introgression population containing genes from the gooseberry tomato LA2093 was used as the test material.The introgression population of the hybrid progeny BC3F1 was further selfed to obtain the BC3F2 generation.Combined with molecular labeling technology,a homozygous and stable single fragment introgression system was constructed.Based on the investigation and analysis of the phenotypic traits of the tomato introgression line BC3F2 generation,the excellent agronomic traits of the introgression line were statistically analyzed,and the complete interval mapping method(ICIM)was used to locate the excellent phenotypic traits.The main findings were as follows:1.BC3F2 line was obtained by self-crossing BC3F1.We then sowed the seeds of BC3F2,obtained plants,investigated the genotype of 573 BC3F2 introgression line population,and constructed a genetic map of BC3F2 introgression system using the mapping software QTL IciMapping combined with complete interval mapping method.The genetic map has a total length of 381.71 cM and 90 molecular markers.On the basis of the genetic map of introgression line,all single plants in the BC3F2 generation introgression line population were screened,and 58 introgression line materials covering 12 chromosomes were selected.There are 43 single-segment strains,13 double-segment strains and 2 three-segment strains.The total length of the infiltrated segment of the 58-minute material is 769.30cM,and the average infiltrated segment length is 10.26cM.Among them,there are 23 pure and genotype strains of donor parents,which can be directly used to improve the genetic traits for cultivated tomatoes.2.Investigat and count 26 phenotypic characters of 573 introgressive plants.Through trait variation analysis,13 traits with large coefficients of variation were selected;correlation analysis and principal component analysis were further applied to these traits to clarify the relationship between different traits,and the content of soluble solids,leaf length,leaf width and four excellent phenotypic traits in leaf growth state;through pedigree analysis,20 lines with excellent traits were selected.This population had the longest leaf length and leaf width and the largest single fruit weight and fruit transverse diameter.3.Using the complete interval mapping method(ICIM)to perform QTL analysis on 13 traits in the BC3F2 population,and a total of 82 QTL sites were detected,including:3 QTL sites controlling the first inflorescence node,located on chromosomes 3,7 and 10;4 QTL sites in the second inflorescence node,located on chromosomes 2,3,10,and 12;8 leaf QTL sites,located on chromosomes 1,2,8,9,11,12 respectively;2 QTL loci for controlling leaf width,located on chromosomes 2 and 8;4 QTL loci for controlling leaf growth,located on chromosomes 1,2,8,and 9;QTL locus for controlling single fruit weight 4,Located on chromosomes 3,4,7,and 8 respectively;5 QTL sites controlling the fruit’s transverse diameter,located on chromosomes 1,2,3,7,and 8;8 QTL sites controlling the fruit longitudinally;Chromosomes 2,3,4,7,8,and 7;7 QTLs controlling fruit shape index,located on chromosomes 2,3,4,5,8,and 10;11 QTLs controlling fruit shape,located on 1.Chromosomes 1,2,4,7,8,9,10,11;11 QTLs controlling the top shape of the fruit,located on chromosomes 2,4,5,6,7,8,12,respectively;11 QTL sites controlling the number of ventricles,located on chromosomes 1,2,4,6,8,9,10,and 11;and 4 QTL sites for soluble solids,located on chromosomes 1,3,6,and 10,respectively. |
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