Eucalyptus has become an important genus in China because it displays adaptability to a wide range of site conditions and produces pulp wood and veneer on short rotations. The aim of this study was to estimate genetic...Eucalyptus has become an important genus in China because it displays adaptability to a wide range of site conditions and produces pulp wood and veneer on short rotations. The aim of this study was to estimate genetic parameters and relationships and consider impli- cations for development of clonal forestry. We assessed growth traits, stem-branch characteristics, crown diameter and height of fresh branch for 20 Eucalyptus hybrid clones in China measured at the age of 44 months. Analysis of variance showed that there were significant differences in growth traits, height of fresh branch and stem straightness among clones. Significant differences in height, volume, crown diameter, height of fresh branch and branch size among replicates were also recorded. Coefficients of vari- ation ranged from 9.84 to 28.54 % for growth traits, 12.03 to 17.25 % for stem-branch characteristics, 18.26 % for crown diameter and 11.73 % for height of fresh branch. Estimates of repeatabilities for height, diameter at breastheight over bark, volume, crown diameter, height of fresh branch, stem straightness and branch size at clone mean level were 0.86, 0.80, 0.80, 0.54, 0.85, 0.77 and 0.44 respectively. Diameter at breast height over bark and height had strongly positive phenotypic and genotypic correlations with volume, ranging from 0.96 to 1.00. The positive genotypic and phenotypic correlations between growth traits and other studied traits suggested that fast growing clones always had bigger crown diameter, higher height of fresh branch, straighter stems and relatively smaller branches.展开更多
Optical emission spectroscopy (OES) was used to study the gas phase composition near the substrate surface during diamond deposition by high-power DC arc plasma jet chemical vapor deposition (CVD). C2 radical was ...Optical emission spectroscopy (OES) was used to study the gas phase composition near the substrate surface during diamond deposition by high-power DC arc plasma jet chemical vapor deposition (CVD). C2 radical was determined as the main carbon radical in this plasma atmosphere. The deposition parameters, such as substrate temperature, anode-substrate distance, methane concentration, and gas flow rate, were inspected to find out the influence on the gas phase. A strong dependence of the concentrations and distribution of radicals on substrate temperature was confirmed by the design of experiments (DOE). An explanation for this dependence could be that radicals near the substrate surface may have additional ionization or dissociation and also have recombination, or are consumed on the substrate surface where chemical reactions occur.展开更多
Heterosis is a quicker,cheaper and easier method for increasing plantation production,and heterosis studies can provide the basis for exploitation of valuable hybrid combinations in breeding programs.Growth traits,woo...Heterosis is a quicker,cheaper and easier method for increasing plantation production,and heterosis studies can provide the basis for exploitation of valuable hybrid combinations in breeding programs.Growth traits,wood properties,and bark percentage were assessed for 6×6 full diallel progenies of E.urophylla in southern China measured at age 4 years.Analysis of variance showed that there were significant differences on all studied traits except dynamic modulus of elasticity among combinations.The mean diameter at breast height,wood basic density,and dynamic modulus of elasticity were 9.40 to 12.20 cm,0.45 to 0.47 g cm-3,and 5.04 to 5.72 GPa,respectively.The coefficients of variation ranged from 18.18%to 50.43%for growth traits,9.07%to 55.24%for wood properties and 22.26%to 23.93%for bark percentage.The heterosis estimation on diameter at breast height,wood basic density,and dynamic modulus of elasticity were-24.07%to 18.74%,-14.23%to 9.17%and-25.53%to 16.28%.U22×U56 generally had higher heterosis of growth traits and wood properties through three sites.Same combinations had different original and reciprocal heterosis estimation at two sites even on same traits.The combinations of same parents always had similar original and reciprocal heterosis estimation.展开更多
Toona ciliate,which belongs to Toona of Meliaceae,is a rare and native timber species in China.However,little progress has been made in the cultivation of Toona ciliate.The height and diameter at breast height of Toon...Toona ciliate,which belongs to Toona of Meliaceae,is a rare and native timber species in China.However,little progress has been made in the cultivation of Toona ciliate.The height and diameter at breast height of Toona ciliata were assessed for fertilization cultivation techniques aged 1 year.Analysis of variance showed that there were significant differences on height among different treatments and replicates and the difference on diameter at breast height among different replicate was also significantly.Treatment with 200 g urea(N>46.5%)+60 g superphosphate(P2O5>12.0%)+100 g potassium chloride(K2O>60.0%)could improve the height and diameter at breast height of Toona ciliate.In summary,more fertilizer could not always improve the growth traits and the site location could affect the growth significantly,therefore more test trials should be carried out before diffusion.展开更多
Breeding is the major procedure in forest research.The basic goal in all of breeding program is to expand the frequency of favorable alleles or the frequency of specific combinations of favorable alleles in the breedi...Breeding is the major procedure in forest research.The basic goal in all of breeding program is to expand the frequency of favorable alleles or the frequency of specific combinations of favorable alleles in the breeding populations through recurrent selection in order to improve the performance of individual plants.During the past three decades,an increase in research on breeding has improved Eucalyptus productivity,and to some extent our standing of their effects on tree growth and on wood properties.Unfortunately,very little information about breeding on the review of Eucalyptus grown in China has been published even though this species was introduced some 120 years ago.This paper reviews the available information regarding research status and prospect of breeding under Chinese ecological conditions and to outline some suggestions to them.According to the present research situation of breeding,we would recommend that:generalizing empirical and useful practices;developing highvalue products;creating more clones for demand;carrying out intensively research over different species and clones for different cultivation goals at different sites over time;above all,applying breeding strategy,especially for multiple generations and interspecific hybrid breeding.展开更多
基金finically supported by the National Twelfth Five-Year Science and Technology Plan ‘‘Breeding of High yield and High Resistance New Species of Eucalyptus’’(2012BAD01B0401),‘‘Genetic Research of Pulp Yield and Veneer of Eucalyptus urophylla Hybrid Clones’’(RITFYWZX201304)
文摘Eucalyptus has become an important genus in China because it displays adaptability to a wide range of site conditions and produces pulp wood and veneer on short rotations. The aim of this study was to estimate genetic parameters and relationships and consider impli- cations for development of clonal forestry. We assessed growth traits, stem-branch characteristics, crown diameter and height of fresh branch for 20 Eucalyptus hybrid clones in China measured at the age of 44 months. Analysis of variance showed that there were significant differences in growth traits, height of fresh branch and stem straightness among clones. Significant differences in height, volume, crown diameter, height of fresh branch and branch size among replicates were also recorded. Coefficients of vari- ation ranged from 9.84 to 28.54 % for growth traits, 12.03 to 17.25 % for stem-branch characteristics, 18.26 % for crown diameter and 11.73 % for height of fresh branch. Estimates of repeatabilities for height, diameter at breastheight over bark, volume, crown diameter, height of fresh branch, stem straightness and branch size at clone mean level were 0.86, 0.80, 0.80, 0.54, 0.85, 0.77 and 0.44 respectively. Diameter at breast height over bark and height had strongly positive phenotypic and genotypic correlations with volume, ranging from 0.96 to 1.00. The positive genotypic and phenotypic correlations between growth traits and other studied traits suggested that fast growing clones always had bigger crown diameter, higher height of fresh branch, straighter stems and relatively smaller branches.
基金the National High-Tech Research and Development Program of China (No.2002AA305508)the National Natural Science Foundation of China (No.50472095)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars (No.2003-14)Beijing Novel Project (No. 2003A13).]
文摘Optical emission spectroscopy (OES) was used to study the gas phase composition near the substrate surface during diamond deposition by high-power DC arc plasma jet chemical vapor deposition (CVD). C2 radical was determined as the main carbon radical in this plasma atmosphere. The deposition parameters, such as substrate temperature, anode-substrate distance, methane concentration, and gas flow rate, were inspected to find out the influence on the gas phase. A strong dependence of the concentrations and distribution of radicals on substrate temperature was confirmed by the design of experiments (DOE). An explanation for this dependence could be that radicals near the substrate surface may have additional ionization or dissociation and also have recombination, or are consumed on the substrate surface where chemical reactions occur.
文摘Heterosis is a quicker,cheaper and easier method for increasing plantation production,and heterosis studies can provide the basis for exploitation of valuable hybrid combinations in breeding programs.Growth traits,wood properties,and bark percentage were assessed for 6×6 full diallel progenies of E.urophylla in southern China measured at age 4 years.Analysis of variance showed that there were significant differences on all studied traits except dynamic modulus of elasticity among combinations.The mean diameter at breast height,wood basic density,and dynamic modulus of elasticity were 9.40 to 12.20 cm,0.45 to 0.47 g cm-3,and 5.04 to 5.72 GPa,respectively.The coefficients of variation ranged from 18.18%to 50.43%for growth traits,9.07%to 55.24%for wood properties and 22.26%to 23.93%for bark percentage.The heterosis estimation on diameter at breast height,wood basic density,and dynamic modulus of elasticity were-24.07%to 18.74%,-14.23%to 9.17%and-25.53%to 16.28%.U22×U56 generally had higher heterosis of growth traits and wood properties through three sites.Same combinations had different original and reciprocal heterosis estimation at two sites even on same traits.The combinations of same parents always had similar original and reciprocal heterosis estimation.
文摘Toona ciliate,which belongs to Toona of Meliaceae,is a rare and native timber species in China.However,little progress has been made in the cultivation of Toona ciliate.The height and diameter at breast height of Toona ciliata were assessed for fertilization cultivation techniques aged 1 year.Analysis of variance showed that there were significant differences on height among different treatments and replicates and the difference on diameter at breast height among different replicate was also significantly.Treatment with 200 g urea(N>46.5%)+60 g superphosphate(P2O5>12.0%)+100 g potassium chloride(K2O>60.0%)could improve the height and diameter at breast height of Toona ciliate.In summary,more fertilizer could not always improve the growth traits and the site location could affect the growth significantly,therefore more test trials should be carried out before diffusion.
文摘Breeding is the major procedure in forest research.The basic goal in all of breeding program is to expand the frequency of favorable alleles or the frequency of specific combinations of favorable alleles in the breeding populations through recurrent selection in order to improve the performance of individual plants.During the past three decades,an increase in research on breeding has improved Eucalyptus productivity,and to some extent our standing of their effects on tree growth and on wood properties.Unfortunately,very little information about breeding on the review of Eucalyptus grown in China has been published even though this species was introduced some 120 years ago.This paper reviews the available information regarding research status and prospect of breeding under Chinese ecological conditions and to outline some suggestions to them.According to the present research situation of breeding,we would recommend that:generalizing empirical and useful practices;developing highvalue products;creating more clones for demand;carrying out intensively research over different species and clones for different cultivation goals at different sites over time;above all,applying breeding strategy,especially for multiple generations and interspecific hybrid breeding.