The Development And Application Of Tomato Foreground And Background Markers

With the development of molecular techniques, molecular marker-assisted selection technology hasbecome a routine mean in tomato breeding. Molecular marker technology has the characteristics of shortcycle and high accuracy, which can analysis the plant genotype and has significant advantages inshortening the breeding process and improving the efficiency of selection. SNP and InDel functionalmarkers were developed based on the tomato gene sequence (foreground marker) and InDel backgroundmarkers were developed based on genome re-sequencing. Using both foreground markers andbackground markers to analysis the tomato materials to improve the selection efficiency and speed upthe breeding process. The main results were as followed:1. According to the tomato gene sequence,7SNPs and1InDel primers were designed for fivedisease resistance genes and two agronomic traits genes, Tm-2, Pto, Sw-5,Ve1,Ty1and ovate, sp.Being verified by material with HRM, the markers above all could distinguish the materials withdifferent genotypes.In addition, the co-dominant SCAR markers PMi developed from Mi gene that hasbeen published was verified in this study and the genotype was completely consistent with the knowngene, so the PMi marker can be used for identification in tomato root knot nematode diseaseresistance breeding.2. A genetic analysis of83tomato materials with PMi marker and Ty1-InDel marker,24tomatomaterials were identified which resistant to root knot nematode and tomato yellow leaf curl virus,9tomato materials were identified which resistant to tomato yellow leaf curl virus,18tomato materialswere identified which resistant to root knot nematode.3.372InDel markers that had been developed were used to make background analysis for the8stable materials in high generation and3groups with different generations. The result showed that theheterozygosity of high generation materials with artificial selection were lower but still difficult toachieve100%of homozygous level. In the3groups with different generations materials,the heterozygosity was reduced after many generations of breeding, but the high generation materialsstill has heterozygosity at the molecular level.4. F2selected individuals of each population were made genetic analysis using backgroundmarkers. The results showed that high genetic similarity were included in the selected plants and this isthe reason that traditional choice has low efficiency. Combined with foreground marker analysis,33plants which have lower heterozygosity and distant genetic relationship had been selected preliminaryfrom the F2selected individuals of4populations.These33plants can be used as the key individuals forthe next round of breeding selection.