Comprehensive Evaluation And Analysis Of Germplasm Resources Of Sophora Japonica

Sophora japonica Linn,also known as Sophora,is a deciduous tree of Sophora L.,Papilionoideae,Leguminosae sp.It is an important,widely planted,widely adapted cultural native tree for ornamental,medicinal,wood,food and other uses.In this study,the germplasm resources of Sophora japonica were evaluated from morphological,molecular biological,physiological and biochemical levels.The main results are as follows:（1）Thirty-seven phenotypic traits,including 31 qualitative traits and 6 quantitative traits,were investigated and analyzed in 1362 germplasm samples of Sophora japonica.The total coefficient of variation of six quantitative traits of Sophora japonica was 20.82%-32.68%,indicating that the quantitative traits of the population of Sophora japonica had abundant variability,among which the coefficient of variation of DBH was the largest（26.61%）.Second,the main dry height,the coefficient of variation is 26.51%;Tree height had the lowest coefficient of variation（22.73%）.The diversity index of 31 quality traits ranged from 3.86 to9.06,and the diversity index of current year branch hair was the largest（9.06）.The diversity index of bark color was 3.86.Among the 31 quality traits,the diversity index of branches was the highest,indicating that the genetic diversity of branches was greater than the diversity of tree,leaf,flower and seed traits.According to the correlation analysis of the quantitative characters of Sophora japonica,the indexes of crown width,DBH and ground diameter can be considered in the selection of the superior varieties of Sophora japonica;Principal component analysis showed that the principal component of sophlocust contained more than70% information of all the measured characters.The first principal component reflected the characters of height,DBH,ground diameter and crown width,and the second principal component reflected the characters of trunk height.In this experiment,the variation of phenotypic characters of Sophora japonica was analyzed,which laid a foundation for breeding excellent varieties of Sophora japonica in the future.（2）At the molecular level,the genetic diversity of germplasm of Sophora japonica was analyzed,and the core germplasm was constructed.Firstly,genetic diversity of 436 germplasm resources of Sophora japonica was analyzed by SSR markers.The results showed that the Pi C of 16 SSR primers were all ≥0.50,indicating that the polymorphism of these primers was good in general,and the polymorphism of loci 2844 and 2128 was high.The average number of alleles（Na）of Sophora japonica germplasm resources was 7.15.The average Shannon’s information index（I）was 1.43.The average number of effective alleles（Ne）was 3.64.The average observed heterozygosity（Ho）was 0.67.The average expected heterozygosity（He）was 0.69,indicating high genetic diversity.Subsequently,molecular analysis of variance（AMOVA）was performed on 436 germplasm collected,which showed that the population variation was mainly from within the population.The 436 samples of Sophora japonica were divided into three subgroups by Bayesian clustering analysis and UPGMA clustering analysis.Among the 436 samples from three provenances,germplasm from different geographical sources were grouped into one group,indicating that geographical isolation had no significant effect on genetic differentiation of Sophora japonica.Then,the core germplasm was constructed by stepwise clustering,and 95 core germplasm were obtained.According to cluster analysis,core germplasm can be divided into three categories.T test showed that there was no significant difference in genetic diversity between the core germplasm and the original population,indicating that the core germplasm retained the genetic information of the original population well.（3）At the physiological and biochemical levels,the changes of three growth indexes and seven physiological indexes of four excellent Sophora japonica cultivars under different concentrations of Na Cl stress were measured.The results showed that with the increase of Na Cl concentration,seedling height,ground diameter and biomass of four sophosa cultivars were significantly inhibited.The activity of antioxidant enzymes increased firstly and then decreased,and reached the peak at 0.2% or 0.4%.Chlorophyll content showed an upward trend.Proline content and relative conductivity increased significantly under Na Cl stress,while MDA content showed a trend of first increasing and then decreasing.Correlation analysis and principal component analysis showed that ground diameter growth,proline and MDA were more sensitive to Na Cl stress.The comprehensive evaluation showed that the salt tolerance of four Sophora japonica cultivars was from strong to weak in order of ’Huaxia’ >Clone 589 > ’Chazi No.1’ > common Sophora japonica,among which ’Huaxia’ and clone 589 had strong salt tolerance and could be promoted as salt tolerant varieties.