Study On Genetic Diversity And Basis Of Development Of Diospyros Glaucifolia Metc

Diospyros glaucifolia is one of deciduous broad-leaved tree species endemic to China. The advantages of fast-growing, adaptation, good wood quality and versatility give it an exciting prospect for development. To conserve the remainders scientifically and utilize it reasonably,we should research current state, genetic diversity and population differentiation of Diospyros glaucifolia. This study would provide the basic data and guideline for future reference when gene resources conservation and genetic improvement would be carried out.After field investigation into the natural distribution of Diospyros glaucifolia, the ecological character of Diospyros glaucifolia populations was analyzed. By morphological and ISSR markers with the experimental materials, the study found out genetic variation and population genetic structure of Diospyros glaucifolia. The growth rhythm of Diospyros glaucifolia at seedling stage was researched as well. The main research results were as follows:(1) Research results of ecological character of Diospyros glaucifolia population:Geographical area of the natural distribution of Diospyros glaucifolia is in the range of 112°16′-119°40′E and 24°21′-30°33′N. The vertical distribution of Diospyros glaucifolia is below an altitude of 1200 meters. The main climate type in the area is sub-tropical monsoon. The population structure of Diospyros glaucifolia was a spindle type. As to the distribution pattern of Diospyros glaucifolia, generally speaking, the distribution pattern of the population was clump, but there still were some differences at various stages of development: clump for saplings, random for adult trees and big trees, and the population showed diffusing trend. The biological and ecological characteristics of the species and competitive exclusion principle caused such differences.(2) Research results of morphological diversity:12 morphological traits of Diospyros glaucifolia from seven populations were selected and investigated. Morphological diversity among/within populations was assessed. The extent and rule of genetic variation in this species were both discussed, too. Results indicated that there were significantly differences in morphological traits among populations and within population. Among different individuals within population, the CV of three morphological traits (in leaf, fruit and seed) was respectively 0.1802,0.1781 and 0.1334,the traits stability of seed was higher than those of leaf and fruit. The morphological differentiation coefficient VST of 12 traits ranged from 20.79% to 48.97%, the mean morphological differentiation coefficient VST of 12 traits was 40.15%, that meant the variation among populations (40.15%)was a bit less than that within populations (59.85%). There existed correlations among 12 morphological traits,at the same time, the morphological traits were also remarkably correlated to longitude and latitude. The UPGMA cluster analysis showed that five groups could be divided from the seven populations.(3) Research results of ISSR genetic diversityThe genetic diversity and population genetic structure in 192 trees from seven natural populations of Diospyros glaucifolia were assessed using ISSR markers. Ten ISSR primers amplified a total of 79 loci, among them, 71 was polymorphic loci. The proportion of polymorphic loci varied from 56.27% to 89.34%, the genetic diversity of Nei's ranged from 0.1687 to 0.3329, and Shannon's index ranged from 0.2518 to 0.4087. Analysis of molecular variance (AMOVA) indicated that 73.98% of the total genetic diversity distributed within population and 26.02% was observed among populations, in accordance with results of the genetic diversity of Nei's and Shannon's index. The UPGMA cluster analysis showed that three groups could be divided from the seven populations.(4)Research results of the growth rhythm and genetic variations of traits at seedling stageThe seedlings sprouted in March, stopped growing at the end of November. The growth period was about 240 days. The growth process of Diospyros glaucifolia at seedling stage could be divided into 3 periods: early growth period, fast-growing period and induration period. Studied on genetic variations of seedling height and base diameter at different stages and different provenances, the results showed there were abundant variations within Diospyros glaucifolia, meanwhile, there were significantly differences among provenances. The differences were mainly controlled by genetic factors. Correlation analysis showed growth of seedling height and base diameter was also remarkably correlated to latitude, average temperature and hours of sunshine.