Genetic Linkage Map Construction And Molecular Markers Of Some Important Traits In Eucommia Ulmoides Oliv.

Eucommia ulmoides Oliv., the single extant species of the genus Eucommia (Eucommiaceae), is endemic to China. The prospects of exploitation and utilization are very extensive, but the breeding programs of Eucommia ulmoides Oliv. is constraining by its narrow genetic background. A powerful tool for early selection of Eucommia ulmoides is provided by development of modern molecular markers. The construction of molecular genetic linkage map and analysis of quantitative traits loci not only provide information for the early selection of important traits but also produce the important significance on map-based cloning and molecular breeding.Based on the F1 permanent mapping population, useing AFLP marker combined the Pseudo-test-cross strategy, the parent-specific genetic linkage maps in Eucommia ulmoides Oliv. were constructed, some important traits were mapped based on the analysis of phenotype date. And two male-specific AFLP markers were identified. The major results and conclusions are described as follows.(1) An AFLP reaction system had been established, and it provided technical supporting for the construction of genetic linkage map in Eucommia ulmoides Oliv. With the analysis of main factors including extraction of genomic DNA method, reaction system of digestion and ligation, pre-amplification and selective amplification processes. The result shows extraction of genomic DNA with improved CTAB method, 500ng template DNA should be used in the digestion system with the reaction for 6 h, the time of ligation should be 6 h, 30 times of dilution for the products of pre-amplification for selective amplification. Repeated results show that it is feasible to use the reaction system constructed by the study to conduct the AFLP analysis of Eucommia ulmoides Oliv.(2) Using 12 selected varieties (clones) as the hybrid parents, a total of 35 crossing combinations were hybridized according to the analysis of mating design. By the way of sowing and culture of seedlings, seven F1 familes have been obtained. Based on the variation analysis of field phenotypic characteristics and detecting the levels of polymorphisms between parents using AFLP, LF×Q1 has been selected as the permanent mapping population for construction the first genetic linkage map in Eucommia ulmoides Oliv..(3) The first AFLP genetic linkage map in Eucommia ulmoides Oliv. was constructed. For the paternal tree of Q1, 108 markers were ordered in 12 linkage groups, covering the total distance of 929.57 cM of Q1 genome, with an average distance of 8.61cM between adjacent markers. For the maternal tree of LF, 14 linkage groups comprising 127 markers were identified, covering the total distance of 1116.08 cM of LF genome, with an average distance of 8.78cM between adjacent markers.(4) Based on the parent-specific genetic linkage maps and analysis the data of phenotypic characteristics in the permanent F1mapping population, the Quantitative Trait Loci (QTL) linked to 8 phenotypic traits was analyzed. 29 QTLs was located in the genetic linkage map, there are 14 QTLs located on the Q1 linkage group, and the other 15 QTLs located on the LF linkage group.(5) Two male specific AFLP markers for Eucommia ulmoides Oliv. which named Eum E3M8-350 and Eum E8M4-279 were identified according to screen 64 primer combinations. The SCAR primers were designed from the sequences of these two determined AFLP fragments. The 350 bp AFLP marker Eum E3M8-350 was converted into a 247 bp male-specific SCAR marker, suggested this SCAR marker can be utilized for early sexual identification in Eucommia ulmoides Oliv. accurately.