| Tomato(Solanum lycopersicum), is one of the most important vegetable the world. Salt damage is one of the major environmental factors seriously affect crop growth and yield formation in the world. According to statistics, about 20% of soil salinization and nearly 50 percent of irrigated arable land are ffected by Salt damage in world’s protected area. Tr anspiration over the soil surface, increased of ground water levels and inadequate of agronomic practices, crop rotation unreasonable, excessive flood irrigation and fertilization is often the main reason which leading to soil salinization. In addition to strengthening and improving the cultivation and management measures, it has great significance to breed new varieties of salt tolerant tomatoes to reducing the harm of soil salinization. Ordinary tomato cultivars are a moderate salt-sensitive plants, generally.Tolerant gene are mostly comes from wild tomatoes, so the phenotype restructuring and marker-assisted breeding can be more effective in breeding new varieties of salt. With the development of quantitative genetics, people have a deeper understanding of plant Genetic laws, which can provide greatly help to breed varieties of new plants, so It has important significance to research the salt tolerance genetic law of tomatoes to accelerate breeding of salt tolerance.Tomato salt tolerance is similar to the quality, yield, stress tolerance and other traits, which are all the quantitative trait loci,and controlled by multi-gene system,the genetic law of them are very complex. In order to study the genetic law,salt tolerance traits correlation analysis, Q TL mapping and screening of germplasmsalt of salt tolerance in Tomato, P 1、P2、F1、F2、BC1 and BC2 six population which were developed from an intraspecific cross between two kinds of tomato with great different salt tolerance zaofen-2 and LA2184 was analyzed. Select the increasing concentration of Na Cl to do some salt stress on germination stage and seedling plants.Do some physiological indicators measured to P1 and P2 seeds, make field survey of salt damage level of six generations(P1- female, P2- male, F1- hybrid generation, F2- hybrid generation, BC1- backcross generation, BC2- backcross generation) seedling plants, identification if Salt-tolerance meets normal distribution, do correlation analysis to all tolerance indices, do gene targeting with Icimapping, construction of genetic maps, take molecular and physiology two methods to filter salt tomato germplasm. Test results are as follows:(1)Salt tolerance of various traits emerged continuously changing trend, which is typical of a normal distribution, indicating that they are quantitative traits. The salt damage level of the six generation were measured. Inheritance of tomato salt tolerance were studied using combination analysis of six generations. The results showed that the model of the salt tolerance was additive-dominance-epistasis model controlled by two pairs of major genes and additive-dominance-epistasis model controlled by polygene,The additive effects of two major genes were 1.3321(da)and 1.3321(db) in this population, respectively. the dominant effects were 1.0380(ha)and 3.5104(hb),the epistatic effects were 1.3256(i),-1.2599(jab),-3.7324(jba) and-1.0049(l), and the hereditability of major gene effect in B1, B2 and F2 generation were 57.91%、34.2%、and 60.11%, respectively.(2)Bud salt tolerance of tomato has a very significant positive and high correlation with germination rate, germination index, and radicle length, whic h indicating that the germination rate, germination index, radicle length can be used as a early indicators screening of alt-stressed seed.Salt tolerance tomato seedling has a very significant positive correlation with POD, CAT, MDA activity,and has a very significant negative correlationhe with content of soluble protein, indicating that POD, CAT, MDA active, soluble protein content and salt tolerance of tomato hasve a close relationship, which can be used as indicators to screen tolerant varieties. t he level of salt injury of tomato seedlings has a significant positive correlation with tomato rosette start position, flower buds of the first flower spike, the second number of flower spike, the third number of flower spike, which can provide the basis for salt tolerance breeding.(3)In the study, 351 SSR markers and 256 AFLP markers were used to screen polymorphism. There are 81 polymorphic markers selected, including 32 SSR markers, the percentage of polymorphism is 11.8%,49 AFLP markers, the percentage of polymorphism was 18.75%.(4)Construct a tomato genetic linkage map acording to the result of primer screenting test. The linkage map had 69 markers, including 21 SSR markers and 48 AFLP markers.The map is the total length of 1312.02 c M, the average distance between markers is 19.58 c M, which can meet the requirements of QTL mapping. The linkage map is composed of 7 linkage groups, the markers uneven distribution in each chain group, 5-23 loci ranged distributed on them, the 5th linkage groups has the most locis, the fifth chain has as many as 23 markers in the group.which distance is 187.63 c M;the 2ed linkage groups has the least locis, the 2ed chain has as many as 5 markers in the group.which distance is 112.09 c M, The shortest distance between two adjacent markers is 0. 73 c M, the longest distance was 52.61 c M. the 4th linkage group has the max average signature, the map distance is 38.71 c M; the 5 linkage groups has the minimum average distance,the map distance 8.16 c M.(5)Using QTL Ici Mapping4.0 software, a total of 4 QTLs were detected for 1 correlation of salt stress trait by inclusive composite interval mapping(ICIM),they were distributed in 3,4,5, and 7 chromosomes, each chromosome have a QTL. NY-1 located between E04M13 and E16M01, the distance to E04M13 is 21.43 c M, the distance was closer to E16M01,which is 3.52 c M, described that E16M01 has close relationship to NY-1. NY-2 located between SSR63 and SSR603, with both distances are 37 c M. NY-3 located between E11M10 and E05M05, the distance to E11M10 is 33.27 c M, the distance was closer to 05M05,which is 28.65 c M, NY-3 has the closer relationship with the latter. NY-4 located between E09M12 and E05M16, the distance to E09M12 is 13.05 c M, the distance was closer to E05M16,which is 23.54 c M, NY-4 has closer relations with the former.(6)Using molecular and physiology two means to screened 50 of germplasm resources by determining their CAT, SOD, POD, MDA, soluble protein content and the ratio of the SSR bands,4 parts of salt tolerance germplasm were screened out f inally. |
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