Variation Regularity Analyzation Of Material Properties And Association SSR Locus Mining For Cunninghamia Lanceolata

Cunninghamia lanceolata(Lamb.)Hook, a very important fast-growing timber species, is widely planted and used in southern mountain areas of China. This experiment used 202 samples from 11 geographic origins of C.lanceolata clones such as Guangxi, Hunan and Guizhou as materials. Four wood traits of the samples( diameter at breast height(DBH), sapwood/heartwood ratio, basic density and crystallinity) were determined to analyze their genetic variation. Genetic diversity and population structure of C.lanceolata clones were analyzed with EST – SSR makers developed independently. Eventually, association analysis depended on phenotypic data and molecular markers were used to find the SSR loci associated with phenotype. The main results are as follows:(1)Based on near infrared spectroscopy, the prediction model of C.lanceolata wood crystallinity was established. Spectrum data were converted to the second derivative spectra. When spectral regions were 6000-4100 cm-1, it showd the best prediction effect with calibration model established by partial least squares method. The tested samples which were not involved in modeling were evaluated, the correlation coefficient reached 0.8751 and the standard deviation was 0.301, which suggested the model had accurate prediction effect.(2) In this study, Four growth traits(sapwood/heartwood ratio, DBH, basic density and crystallinity) were detemined, each index showed extremely significant difference among clones. The results showed that the variation coefficient of sapwood/heartwood ratio, DBH, density was 29.54%、18.20%、8.18 espectively, which suggested that there were big genetic differences between growth and wood traits in the selected group.(3) The analysis of the characteristics of microsatellite distribution, this experiment also independently developed 42 polymorphic primers, accounting for 17.65% of the total designed primers. Based on main allele frequency, Shannon ’s information indices and PIC values, the selected fir group had a certain degree of genetic diversity, which could be divided into three sub-groups with population structure analysis. Besides, the average D′ value of SSR loci combination of the selected group was 0.308, linkage disequilibrium existed between 46 loci combinations under Significance level(P < 0.001). 12 gene loci associated with growth traits were selected with the correlation analysis between polymorphic SSR molecular markers and material properties,, the relationship between allelic variations of each locus varied from similarity, differences or complementarity. There were differences between mean value of allelic variation positive and negative effects of associated marker locus, which we could choose a suitable locus and the corresponding allelic variation according to the breeding requirement. The same marker loci could be associated with two characters, and different directions and sizes of phenotype effects existed in allelic variation on different characters.