QTLs Mapping For Tomato Fruit Weight, Shape And Soluble Solid Content In Solanum Lycopersicon × Solanum Galapagense Recombinant Inbred Line

The tomato wild species S.galapagense(also called L.cheesmanni minor) derived from galapagos islands which is the only one separately evolutionary tomato species away from tomato evolutionary center Peru, thus contains a lot of special genes. It is of great importance to find and utilize these genes.The BC2S7 and BC2S8 groups used in our research which established by S.galapagense LA0317(male) and cultivate tomato 9706(female) both contain 130 strains and present great variations in stem height, fruit weight and shape, fruit ripening time, fruit soluble solid content and so on. Based on the great variations, we conduct QTL analysis on fruit shape, weight and soluble solid content. And the results are as below:1. Establishment of genetic linkage mapA total of 150 SSR, 23 CAPS and 120 Indel polymorphism makers are used to conduct Genome-wide genotype analysis to 130 strains of BC2S7 group. The Joinmap 4.0 was used to establish a linkage map which contains 15 linkage groups including 93 SSR makers, 18 CAPS makers and 81 Indel makers. The total length of the linkage map was 770.6cM, and the average distance between two makers is 4.0cM. Each of chromosome 1, chromosome 2, and chromosome 9 contains two linkage groups and the other nine linkage groups respectively note one chromosome.2. QTL analysis of fruit weight and shapeQTL analysis of tomato fruit weight and shape was conducted by multiple QTL model(MQM) method in MAPQTL4.0. 18 QTLs were detected associated to these fruit morphological traits in total. The LOD values of these QTLs were between 2.40~5.17 and they can explain 8.0%~32.4% phenotypic variations. Eight QTLs can explain more than 10% variations. Among these QTLs, five QTLs were related to fruit weight and the addictive effects were all negative, six QTLs were related to fruit shape index, only two QTLs were related to fruit length and five QTLs related to fruit width. In addition, we detected several QTLs controlling different morphological traits clustered at some molecular makers such as SSR135, Indel_FT-77, TMS66 and Indel_FT-143, which indicated that these pleiotropic loci may simultaneously have impacts on different fruit morphological traits.3. QTL analysis of fruit soluble solid content and screening of high soluble solid content tomatostrainsBoth of BC2S7 and BC2S8 groups were used to conduct QTL analysis to tomato fruit soluble solid content. Five QTLs were detected in BC2S7 groups and four QTLs were detected in BC2S8 group, and among these QTLs two QTLs were detected in both groups. The QTL qssc-9-1 is noteworthy because its physical position coincides perfectly with Brix-9-2-5. Finally we make sure they are same. The other QTLs are all novel QTLs. Among these 130 strains, we total screened five strains whose average soluble solid content of two seasons are higher than 8, two strains whose fruit weight are higher than 90 gram and soluble solid content are higher than 5.5. Compared with the former five strains, the latter two contain less linkage drags and have higher values.