Genetic Diversity Of Natural Population In Picea Asperata Mast.

Picea asperata Mast, is one of the most important indigenous tree species used for the production of pulp wood and timber, and it is a prime reforestation species in western China. Most of natural stands were felled in history ,some gene resources had been lost. The remainders had been presenting "island pattern " distribution. In order to conserve the remainders scientifically and utilize rationally, it was necessary to make clear genetic diversity (GD) and population differentiation within the species. This study could provide the theoretical references and basic data for the gene resources conservation and genetic improvement in this species.Based on field investigations and analysis of the natural distribution of P. asperata, 30 individuals of ten populations were confirmed, 50~60 cones and 40 two years needles of 2 years were sampled per individual. This study was conducted by morphological, enzyme and SSR different methods with the same experiment materials(300 individuals of 10 populations, 30 trees from each of 10 populations)to determine genetic variation of natural populations and find out the relation between genetic variation of natural populations and different distribution areas in P. asperata. 3 different kinds of methods of GD (morphology, isozyme and SSR)were analysed and evaluated by comparision.The cone germplasm resources was preliminarily established and the conservation measures had been put forward , meawhile, the habitants division of natural populations had been carried out according to rules of revealed GD in P. asperata.The main research results were as follows.(1) Research results of morphological diversityFour cone characters, three needle traits, three seed scale traits, three seed wing characters and four seed traits in 30 trees from each of 10 populations in P. asperata were selected and investigated. Morphological diversity among/within populations were discussed on the basis of 17 phenotypic traits analysis such as the cone, the needle, the dry weight of cone, the seed scale, the seed wing, the seed and the weight of per 1000 seeds and so on . The method of ariova analysis, multi- comparison, relatedanalysis and hierarchical cluster analysis of were used for analysis of experimental results. The results of research showed that there was significantly difference in morphological characters among populations and among individuals within population. In different individuals within populations, the CV of five phenotypic traits(in cone, needle, seed scale, seed wing and seed traits) were 19.14%, 26.46%, 13.58%, 19.78 % and 17.40 % ,respectively. The traits stability of seed scale was higher than that of other morphological traits. The VST of cone , needle, seed scale, seed wing and seed ranged from 2.09% to 40.62% .The mean phenotypic differentiation coefficient VST of populations was 30.99%. It also showed that the variation among populations(30.99%) was greatly smaller than that within populations (69.01% ) .The order of CV within populations was as follows: Tiebu population (19.51%) >Zhuonipopulation (18.87%) >Aba population (17.30%) >Linpo population (17.11%) .The repeatability of cone, needle, seed scale, seed wing and seed was 0.570, 0.619, 0.490, 0.389 and 0.260, respectively.The order of morphological repeatability was Tiebu>Zhuoni> Rewugou> Chuanpan> Aba> Baxi> Xiaojin> Dalu> Linpu>Heishui. The cone length, cone diameter, seed scale length and the weight per 1000 seeds were the most important phenotypic traits which were easy to measure in P. asperata. The traits variation of natural populations within species affected mainly by latitude in spatial distribution. The 10 populations of P. asperata investigated could be divided into five groups according to the UPGMA cluster analysis.(2) Research results of isozyme diversityThe genetic diversity of ten populations of picea asperata in west part of China was assessed using allozyme analysis by horizontal sliceable starch gel eletrophoresis and vertical slab polyacrylamid gel electrophoresis. Seventeen loci (27 alleles) of 8 enzyme sy...