The Research Of Phenotype Analysis And CAPS Marker For Fruit Traits In Melon

China is the great producer and consumer of the melon. The planting area and yield of the melon are ranked first in the world. As an important type of fruit vegetables, the work of breeders is focused on breeding high quality melon,such as good taste, thick flesh and excellent storage capacity. In this paper, in order to understand the physiological changes in the melon pericarp development process, the researchers observe the organizational structure of pericarp during melon fruit development at first. Second,by means of high-throughput sequencing and bioinformatics analysis, develop polymorphism CAPS molecular markers on the whole genome, search the loci associated with melon pericarp traits, to reveal the genetic mechanism of the melon pericarp thickness from two aspects together. In order to establish theoretical and material found ation for breeding high quality melon by molecular techniques.The thick skin melon Elizabeth（M4-5） and thin skin melon M1-15 showed a significant difference in pericarp.The two parents were hybridize for F₁ generation,then getting F₂ generation by F₁ generation selfing. The microstructure observation by scanning electron microscope were for heredity of pericarp. CAPS markers were developed by the high-throughput re-sequencing method to construct the linkage map and fine mapping QTLs related with melon pe ricarp and other traits. Specific results are as follows:1.The microstructure observation of melon pericarpMelon pericarp contained exocarp,mesocarp and endocarp. The fleshy mesocarp and endocarp of melon were edible part,which was called flesh. The exocarp of melon was composed of epidermis hair and stoma.The stomas falled off gradually from the exocarp with fruit development,which inflicted the wound.The wound was also healed with fruit development. The edible pericarp of melon which contain mesocarp and endocarp was consisted of parenchyma cell throughout vascular bundle.There is big difference between the exocarp of thin skin melon and thick skin melon by comparison. there is a quite thick cuticle formed on the surface of exocarp,while there is no thick cuticle formed on the surface of thin skin melon exocarp.Both the two kinds of exocarp were composed of one layer of cells.The edible part both were consisted of parenchyma cell.2.Phenotype analysis for pericarp-related and fruit-related traits in melonPericarp-related traits contain the type of exocarp, exocarp thickness, edible pericarp thickness, pericarp firmness and pericarp cracking. The study found that the type of exocarp is quality trait, while exocarp thickness is quantitative trait.But there is a clear correspondence between the type of exocarp and exocarp thickness. Edible pericarp thickness, pericarp firmness, and fruit-related are also quantitative traits. And there is a significant correlation between pericarp-related and fruit-related traits3.Construction of Genetic Linkage MapThe present study was to develop SNPs based on the resequencing data and bioinformatics methods of M4-5 and M1-15 and convert them into cleaved amplified polymorphic sequence（CAPS） markers. In this study, we developed 523 CAPS markers totally and 223 markers showed polymorphism between parents, the polymorphism rate is 4%. We markered F₂ generation using CAPS markers and constructed a genetic map.The map contained 195 markers and grouped on 12 linkage groups, spanning a total length of 1702.55 c M, with an average of 8.78 cM between markers.4.CAPS marker analysis for Pericarp-Related and Fruit-Related TraitsA total of 40 locus for pericarp-related and fruit-related traits were located using Ici Mapping V3.3 software. A total of 12 locus for pericarp-related traits which contain 2 locus for the type of exocarp, 2 locus for exocarp thickness, 4 locus for edible pericarp thickness, 1 locus for edible pericarp firmness and 3 locus for pericarp cracking mainly located on linkage group 3,5,6,7,9 and 11 with contribution rate range from 3.6743% to 72.9145%. A total of 28 locus for friut-related traits which contain 14 locus for fruit,9 locus for yield and 5 locus brix content with contribution rate range from 3.4974% to 17.9684%...