Progeny Test on the Natural Populations and Selection of Excellent Populations from Fraxinus Mandshurica

Fraxinus mandshurica is one of the ancient relict flora species originated from the Tertiary period, which is mainly produced in the eastern mountains in Northeast China. It has an important scientific value for studying the Tertiary flora and the Quaternary glacial climate. In order to make rational use of the natural genetic resources of F. mandshurica , and to increase the scientific and technological added value of improved varieties, this study used the method of positional observation of fixed standard fields to discuss the genetic variations of tree height and DBH of the natural populations and its open-pollinated progenies, systematically analyze the heritability and genetic gains in growth characters based on the analysis of progeny test, growth dynamic and heredity effects. The populations with good growth, stress resistance and adaptability were selected. The results showed that there were extremely significant difference in the growth characters among the natural populations, and the coefficients of variance for tree height （22.99%） were smaller, while the coefficients of variance for DBH （41.37%） were larger. On the other hand, there were extremely significant differences in the growth characters among the open-pollinated progenies, and the interaction between these progenies and the blocks was significant. Meanwhile, the growth characters had strong heritability, high genetic gain, and remarkable heredity effects. The heritability of tree height and DBH were 0.825 and 0.781, and the genetic gains were 15.16% and 25.85%, respectively. Therefore, Shanhetun （SHT） and Xinglong （XIL） were determined to be excellent natural populations both in the growth, resistance and adaptation with growth traits as the main evaluation index, which could be widely applied in the advanced generation improvement breeding.

Patterns of variation in chemical compositions of wood from natural populations of Pinus manssoniana Lamb.in Guizhou Province,China

Patterns of variation in the chemical composition of wood, i.e., holocellulose, cellulose and lignin contents and 1% NaOH extractives were studied in 12 natural populations of Pinus manssoniana Lamb. in Guizhou Province, China, using wood cores as experiment material. The results show statistically significant differences among provenances in holocellulose, cellulose and 1% NaOH extractive contents. The largest coefficient of variation among the provenances was found in the 1% NaOH extractive content and the smallest in the holocellulose content. Variation of lignin content occurred within provenances. Correlations between chemi- cal compositions of wood and factors of local geography and meteorology were largely insignificant. The chemical composition of wood presented patterns of random variation. The correlation of 1% NaOH extractive content with holocellulose content was sig- nificant （r = -0.68）. There was also significantly negative correlation （r = -0.62） between cellulose and lignin content. On the basis of a UPGMA cluster analysis, we identified three provenances of masson pine among the 12 studied, i.e., those of Wengan, Tongzi and Luodian with high cellulose contents, low levels of 1% NaOH extractive and moderate lignin contents, which we recommend as promising provenances for growing of pulp wood and the manufacture of paper in Guizhou Province.

Study on the cytoplasmic incompatibility in some natural population of Culex pipiens complex in China and Japan

The cytoplasmic incompatibility in the field population of Culex pipiens complex from China and Japan was studied. The results of the crossing experiments between 11 different strains suggest that some Japanese strains might be possible to be used for control Chinese strains by using male sterile technique, and the heavy infection of wolbachiae in mosquitoes may have some relations with the cytoplasmic incompatibility in the field population of Cx. pipiens complex.

Life Table of Natural Population of Gastrolina depressa

[Objective]The paper was to understand the population development regularity of Gastrolina depressa in natural environment in Guizhou Province.[Method]The population dynamics of G.depressa was studied by establishing life table of natural population of G.depressa via field observation and calculating dynamic trend index of population.[Result]The mortality rates in egg stage,pupal stage and adult stage accounted for 26.42%,10.96%and 8.22%of the total mortality rate,respectively.The mortality rate in larval stage was the highest,accounting for 54.40%of the total mortality rate,higher than the total mortality rate in the other three stages.The population dynamic trend index I=9.25,I>1 indicated that the population showed an upward trend.[Conclusion]Under the natural conditions,the population of G.depressa shows upward trend,and human intervention is needed to control the population.The larval stage is the weak stage of the insect,which is the best time to control the insect.

Geographical differences of leaf traits of the endangered plant Litsea coreana Levl.var.sinensis and its relationship with climate

Seventeen morphological and anatomical characteristics of the leaves were selected from five natural populations to explore the variation in leaf traits of Lits ea core ana var.sinensis and the effects of geographical environment on these variations.Nested analysis of variance,multiple comparisons,principal component analysis(PCA),and correlation analysis were conducted to explore the variations within and between populations and their correlation with geographical and climatic factors.Significant differences in the 17 leaf traits were observed within and among populations.On average,the relative contribution of within population variation to total variation was 24.8%,which was lower than among population variation(54.6%).The average differentiation coefficient of the traits was 65.8%,and the average coefficient of variation 11.8%,ranging from6.7%for main vein thickness to 21.4%for petiole length.The PC A results showed that morphological characteristics were divided into two categories,and the level of variation was greater than that of leaf anatomy.Most of the leaf traits were significantly correlated with geography and climate and showed a gradual variation with longitude,latitude,and altitude.In areas with high temperatures,less rainfall,and strong seasonal rainfall,the leaves are larger,longer and thicker.This study shows that variations in leaf traits of L.coreana var.sinensis mainly come from variations among populations.The level of trait differentiation among populations is high and the level of variation within populations low.These findings help further understand leaf morphological characteristics of this species and can provide a valuable reference for the protection and sustainable utilization of this natural resource.

Leaf phenotypic variation of endangered plant Tetracentron sinense Oliv.and influence of geographical and climatic factors

To analyze the degree and pattern of phenotypic variation in leaves of Tetracentron sinense Oliv from the perspective of genetic and environmental adaptation and thus contribute to effective evidence-based conservation and management strategies for germplasm resources,we measured 17 morphological and epidermal micromorphological leaf traits from 24 natural populations of T.sinense.Nested analysis of variance,multiple comparison,principal component analysis(PCA),cluster analysis,and correlation analysis were used to explore phenotypic leaf variation among and within populations and potential correlations with geographic and environmental factors.There were significant differences in 17 leaf phenotypic traits among and within populations.The mean phenotypic differentiation coefficient of the 17 traits was 56.34%,and the variation among populations(36.4%)was greater than that within populations(27.2%).The coefficient of variation(CV)of each trait ranged from 4.6 to 23.8%,and the mean was 11.8%.Phenotypic variation of leaves was related to environmental factors such as average annual sunshine hours,average July temperature,and average annual rainfall.The variation changed along gradients of longitude,latitude,and altitude.The PCA clustered the 24 natural populations into four groups.Our study suggests that phenotypic variation in T.sinense occurred primarily among populations,with moderate levels of phenotypic differentiation among populations and low levels of phenotypic variation within populations.The plant’s poor adaptability to the environment is likely an important contributor to its endangerment.Accordingly,conservation strategies are proposed to protect and manage the natural populations of T.sinense.

The Questions On Jun Zhu′s Paper: A Model of the Age Patterns of Births by Parity in Natural Fertility Populations

When we read Mr. Jun Zhu′s paper: a model of the age patterns of births by parity in natural fertility populations published in Mathematical Population Studies, Vol.4(3), pp.153～173, 1994, it really surprised us by his creative ideas and perfect results. We studied the paper deliberately because it is a remarkable work, and could be a significant contribution to the modeling of fertility analysis. As some contents not perceivable to us, we would expect to discuss with Mr. Jun Zhu to make a clear comprehension of the models in the paper. Our aim is to lead the models and the theory more reliable and practical.

Serum vitamin D levels of the natural population in eastern China

Objective To assess vitamin D levels in eastern China by a standard measurement.Methods The data were from a 2014 Survey on the Prevalence in East China for Metabolic Diseases and Risk Factors-China data base.There were 12 662 subjects included in this cross-sectional study from February 2014 to June 2016.We assessed the vitamin D levels of natural population by