Construction Of Genetic Linkage Map By SSR And QTL Mapping For Resistance Of Acaphylla Theae, Sunscald And Anthracnose In Tea Plant(Camellia Sinensis)

China is the original country of the tea plant [Camellia sinensis (L.) kuntze]. And in the process of cultivated, it come into being abundant germplasm resources of tea plants by natural and artificial selection for a long time. In recent years, the molecular biology researches of tea plant which refer to evolutionary relationships, genetic diversity and variable characteristic, genome structure and cloning of function genes had been increasing deepening. Indeed, it had become a major content for molecular breeding of tea plant that using molecular markers for assisted breeding in tea plant, constructing genetic linkage map, QTL (Quantitative trait loci, QTL) mapping of quantitative traits and excavating functional genes. In this study, we used the petal assisted method of artificial pollination to construct the mapping group of F1. And then, based on SSR (Simple sequence repeat, SSR) markers, we detected the purity of F1 group and constructed the genetic linkage map. Finally, in order to provide theoretical foundation for excavating functional genes and map-based cloning, we used genetic linkage map and the phenotype data of acaphylla theae, sunscald and anthracnose to QTL mapping. At last, the main research results of this study as follows:1. The study identified the purity for 184 individuals which were sampled from F1 group of W×L with 32 selected simple sequence repeat, aiming at proving the method is beneficial to structure pure F1 group and confirming how much number of SSR markers are suitable for identification. As the consequence of parentage analysis,9 false-hybrid individuals (4802.4806,4901.4910.5117.5301,5314,5418 and 5513), the genotypes between offspring and parents were inconformity with Mendel's law of segregation, were detected and the rate of false-hybrid only 4.89% at 95% confidence. And mismatch loci ranged from 2 to 9. Meanwhile,1-2 SSR markers selected from each linkage group or chromosome randomly were recommend as a suitable quantity for SSR identification which could give consideration to accuracy, cost and efficiency.2. the 194 SSR markers, polymorphism and clearly separate bands, were selected from 300 primary SSR markers by using six Fl individuals and parents of WNZ(?)×LJ43(?) as materials. And the selected markers were 64.7% of the total. Among the selected markers,68 of them came from maternity (35.1%),27 of them came from paternity (13.9%) and 99 of them came from parents (51.0%). Furthermore,34 markers of segregation distortion,17.5% of the total, were detected by using Chi-square testing. In addition, according to Chi-square testing,9 markers of severe segregation distortion were excluded before genetic mapping.3. The genetic linkage map was constructed by 185 SSR markers and 174 Fl plants of WNZ(?)×LJ43(?) which had been selected by Chi-square testing and purity identification respectively. The maternal and paternal genetic maps were constructed respectively according to double pseudo-testcross strategy. The result showed that the maternal genetic map had 15 linkage groups that were composed by 147 SSR markers, and the map distance and average distance was 1087.2cM and 7.4cM respectively. And the paternal genetic map had 15 linkage groups that were composed by 111 SSR markers, and the map distance and average distance was 950.7cM and 8.6cM respectively. Furthermore, the integration map had been got by using anchor markers of parents to combine parents genetic map. And the integration map had 16 linkage groups that were composed by 175 SSR markers, and the map distance and average distance was 1165.4cM and 6.7cM respectively. Interestingly, LG15 and LG16 of the integration map were found that they belonged to the same linkage group in fact after comparing with other research. We speculated that the less quantity of SSR markers and bigger gap in this linkage group leaded to the fracture.4. Four QTLs, came from four genetic linkage groups (LG03, LG06, LG11 and LG13), were detected in six different linkage groups by QTL analysis for the resistance of acaphylla theae. The LOD and PVE of individual QTLs ranged from 2.75 to 3.14 and 7.2% to 13.0%, respectively. A main QTLs with LOD 4.06 and PVE 16.5% were detected in LG 11.5. Four QTLs, came from three genetic linkage groups (LG01, LG04 and LG06), were detected in six different linkage groups by QTL analysis for the resistance of sunscald. The LOD and PVE of individual QTLs ranged from 2.72 to 4.33 and 6.9% to 69.8%, respectively. Two main QTLs with LOD 4.06, PVE 16.5% and LOD 4.33, PVE 69.8% were detected in LG01 and LG04.6. A pathogen was isolated from a diseased leaf of the F1 plants of LJ43(3)×BHZ(?), and its gene sequence of ITS had 99% similarity with Colletotrichum sp. based on NCB1 BLAST. The plants grown in open field were more easy to be infected by the pathogen than those grown in rooms. Eight QTLs. came from six genetic linkage groups (LG03, LG06, LG08, LG10, LG13 and LG15), were detected in six different linkage groups by QTL analysis for the resistance of anthracnose. The LOD and PVE of individual QTLs ranged from 2.53 to 6.80 and 5.6% to 13.8%, respectively. A main QTL with LOD 6.80 and PVE 13.8% was detected in LG10.