Comparative growth,dry matter accumulation and photosynthetic rate of seven species of Eucalypt in response to phosphorus supply

Plantations of eucalypts as short-rotation tree crops are rapidly expanding in tropical and sub-tropical regions, including southern China, where the soils are acidic and available phosphorus(P) is limited. We investigated seedling growth, dry matter accumulation, and the dynamics of photosynthetic rate and chlorophyll content of seven Eucalyptus species/hybrids(E. dunnii, E. grandis, E. grandis × E. camaldulensis, E. urophylla × E. camaldulensis, E. urophylla × E. tereticornis, E. grandis × E. tereticornis, E. urophylla × E. grandis) in response to different levels of P supply(0, 6, 12 and 18 mg?kg-1 KH2PO4). The photosynthetic rate and the chlorophyll content significantly declined as the P supply declined in almost a linear fashion for all species as the P stress period extended. In the absence of P supply, height growth of seedlings of all species was significantly impaired, while root collar diameter growth and whole plant dry matter accumulation was not affected by the level of P supply in most of the species. Significant inter-species variations in growth, dry matter accumulation and photosynthetic rate in response to P supply were detected. Eucalyptus dunnii had the lowest growth performance across all levels of P supply while E. urophylla × E. tereticornis showed superior growth performance. From a practical point of view, E. urophylla × E. tereticornis is suggested as a candidate hybrid for planting on slightly P-deficient sites in southern China while E. dunnii, being a slow-growing species, is not suitable for short-rotation plantation. On plantation sites where severe P deficiency exists, P fertilization needs to be considered to boost rapid growth of seedlings so as to meet the management objectives of short-rotation plantation.     

大花序桉种源/家系遗传变异与早期选择研究

大花序桉(Eucalyptus cloeziana)是生产锯材的潜力树种之一,对其进行了种源/家系早期选择研究,结果表明:2.5年生试验林的平均树高和胸径分别为7.45 m和7.10 cm,且各指标在种源和家系水平上都存在极显著差异;树高、胸径及材积的遗传力随树龄的增加而增大,2.5年生时树高、胸径及材积的遗传力分别为71.1%、75.1%和68.5%;早期选择的家系胸径和材积具有较高的遗传增益,分别达到12.68%和25.26%,树高仅为6.68%,因此家系在早期选择时将更多考虑材积和胸径因子。用指数选择法选出20729等8个种批和C4-139等20个家系为推荐的潜力优良材料。     

桉树胶合板材林栽培与无性系早期选择

对GR518等10个桉树无性系胶合板材测定林1.5年生生长及栽培模式进行选择和评估研究,结果表明：早期生长中修枝对生长影响较小,各修枝水平间生长差异不显著,而随着林分密度的增加,无性系生长性状有增加的趋势;不同无性系树高、胸径、单株材积及单位面积蓄积生长水平均存在极显著差异,而生长性状除树高外,另外3个指标在无性系与区组的交互效应上也存在显著差异;经单位面积蓄积的多重比较,KC29、GR518和DH32-28在10个无性系中生长最优、保存率高,是今后胶合板材优化培育模式研究中值得重视的无性系;不同性状无性系重复力较高,说明选择在该地进行示范的所有参试无性系能较好地保持亲本优势且稳定遗传,符合进行示范的选择要求,在30%入选率下,性状遗传增益在11.29%~51.80%之间。     

重庆桉树无性系引种评价与选择效果

以无性系DH3229、EC14、C6、巨桉、尾叶桉U6为参试品种,对参试品种3年生林的各项生长指标、抗逆性指标等进行了系统观测、评价。其结果表明,桉树耐低温寒害、耐高温干旱是重庆地区抗逆性状的核心指标,DH3229速生丰产树种可作重庆西部低海拔生态区域的优良种源,其无性系种苗可用于重庆地区退耕还林、速生丰产林、园林绿化。本项研究结果扩大了尾巨桉DH3229的种植范围。     

桉树杂种无性系生长和木材密度的选择

对以尾叶桉为母本、细叶桉等5个树种为父本的79个桉树杂种无性系进行了生长和木材密度的选择研究,性状包括9月生树高和80月生木材密度以及68、80、91和103月生树高、胸径和材积.结果表明:无性系间的差异在各性状上均达0.001极显著水平;各性状的重复力介于0.21~0.48之间,受低到中等程度的遗传控制;性状间表型相关均达0.001显著水平.本研究选出生长和木材密度均高于对照DH32-29的尾叶桉 ? 细叶桉杂种优良无性系8个,103月生平均单株材积为对照的101.5%~126.1%、80月生平均木材密度为对照的121.1%~147.4%,这为下一步的无性系中试提供了备选材料.     

巨桉种源早期生长对比及综合评价

对7个巨桉(Eucalyptus grandis)种源4a生时的生长性状进行测定分析,利用主成分分析结合模糊聚类法对各种源进行综合评价.结果显示:(1)7个种源间存在分化和差异,其中15508号种源平均树高及单株材积最大,分别为10.48 m、0.022 8 m3;13019号种源平均胸径和保存率表现最优,为8.09 cm和79％;种源16500号干形生长表现最优.(2)树高、胸径与单株材积三者与干形、保存率及海拔间均存在负相关;保存率与南纬、东经呈现显著正相关(P＜0.05),与海拔呈现负相关;干形与南纬、东经呈现负相关,与海拔间呈正相关.(3)基于主成分分析确定巨桉种源树高、胸径、单株材积、干形及保存率指标所占权重分别为:0.267 5,0.262 9,0.266 8,0.163 5和0.039 3.(4)根据综合评分及模糊聚类,第Ⅰ类种源(种源13019、15508、15875和16500)生长表现最优,适宜在引种地种植,其余种源可通过进一步测定选择优良个体作为世代育种材料.     

我国桉树种质资源现状及育种目标探讨

我国引种桉树的历史已经超过120 a,收集和保存了大量的桉树种质资源,这是桉树育种工作的基础。育种目标是育种工作者首先要明确的问题,是指培育的品种应具备哪些主要性状,育种目标制定恰当与否是决定育种工作成败的关键。本文回顾了我国桉树种质资源的收集、保存及利用现状,对桉树育种目标体系的建立进行了总结和讨论,旨在为我国桉树育种研究提供理论指导和技术参考。     

Identification,pathogenicity and control of powdery mildew caused by Erysiphe elevata on Eucalyptus pellita in Sumatra,Indonesia

Powdery mildews are biotrophic ascomycetes that do not typically kill their hosts, but instead interfere with normal plant growth. In Indonesia, white powdery spots were observed forming on the upper part of fully developed leaves of Eucalyptus pellita planted in sand beds of a clonal nursery. Thus, this study aimed to identify the causal agent of eucalypt powdery mildew in Indonesia as well as to develop control strategies to better manage the disease. Pathogen identification was based on morphology, molecular characterization of DNA sequencing the ITS region and pathogenicity test. In addition, considering that some powdery mildews are inhibited by free moisture on leaves, efficacy of foliar watering was tested for disease control. Phylogenetic analyses showed that isolates collected from infected eucalypt plants grouped together with other sequences of the Erysiphe elevata clade with bootstrap support of 99%; a similar result was also confirmed by morphological observations. Pathogenicity of powdery mildew on eucalypt plants was confirmed through artificial inoculation, thus fulfilling the Koch's postulates. For disease control, foliar watering reduced the incidence of powdery mildew on mother plants. The reduction of the disease incidence began to be more evident at 2 weeks after trial establishment, and in the fourth week, the incidence was below 10% in all three treatments, while the control was above 20%. Therefore, we concluded that E. elevata is the causal agent of powdery mildew in Indonesia and that one application of foliar watering per week was enough to minimize the disease impact in the nursery.     

Comparison of estimators and feature selection procedures in forest inventory based on airborne laser scanning and digital aerial imagery

Digital maps of forest resources are a crucial factor in successful forestry applications. Since manual measurement of this data on large areas is infeasible, maps must be constructed using a sample field data set and a prediction model constructed from remote sensing materials, of which airborne laser scanning (ALS) data and aerial images are currently widely used in management planning inventories. ALS data is suitable for the prediction of variables related to the size and volume of trees, whereas optical imagery helps in improving distinction between tree species. We studied the prediction of forest attributes using field data from National Forest Inventory complemented with ad hoc field plots in combination with ALS and aerial imagery data in Aland province, Finland. We applied feature selection with genetic algorithm and greedy forward selection and compared multiple linear and nonlinear estimators. Maximally around 40 features from a total of 154 were required to achieve the best prediction performances. Tree height was predicted with normalized root mean squared error value of 0.1 and tree volume with a value around 0.25. Predicting the volumes of spruce and broadleaved trees was the most challenging due to small proportions of these tree species in the study area.     

Susceptibility of Eucalyptus grandis and Acacia mearnsii seedlings to five Phytophthora species common in South African plantations

Eucalyptus grandis and its hybrids, as well as Acacia mearnsii, are important non‐native trees commonly propagated for forestry purposes in South Africa. In this study, we conducted pathogenicity trials to assess the relative importance of five commonly isolated Phytophthora spp. (Phytophthora alticola, P. cinnamomi, P. frigida, P. multivora and P. nicotianae) from the plantation environment on E. grandis and A. mearnsii seedlings. Overall E. grandis was more susceptible to the tested Phytophthora spp. than A. mearnsii. Phytophthora cinnamomi was the only pathogen that had a significant negative effect on both the host tree species, leading to a reduction in root and shoot weight as well as to death in the case of E. grandis. Phytophthora alticola and P. nicotianae exclusively affected E. grandis and A. mearnsii, respectively. This study updated the current knowledge on the pathogenicity of Phytophthora spp. on two important non‐native commercially propagated tree species from South Africa.     

Examination of the consistency of plant traits driving oil yield and quality in short-rotation coppice cultivation of Eucalyptus polybractea

The value of eucalyptus oil for medicinal purposes is based largely on its cineole content. The prime commercial species for cineole production in Australia is Eucalyptus polybractea (blue mallee). Despite the long history of blue mallee harvesting in Australia, there has been little research on the establishment of plantations of the species or on the efficacy of short-rotation coppice cultivation with respect to the consistency of oil yield and quality from rotation to rotation. This study aims to assess if subsequent coppice oil traits reflect sapling traits and if the coppice oil traits under short-rotation cultivation are consistent from one rotation to the next. A trial plantation was established in a key eucalyptus oil harvesting district in Victoria. Firstly, the oil-related traits of 20 saplings harvested 3.5 years after planting were compared with those of their subsequent coppice harvested after 12 months regrowth. Despite the expected differences in total biomass, the oil-related traits of blue mallee saplings were mostly well reflected in their subsequent coppice. Total above ground biomass and foliar oil concentration were significantly related between saplings and coppice, and cineole proportion showed a Pearson's correlation of 0.93 between harvests. Nevertheless, the mean foliar oil concentration in the coppice was 148 mg g⁻¹ dw compared with 107 in the saplings, and the coppice foliage, on average, showed significantly reduced cineole with a mean of 87% in the saplings (maximum of 95.6%) compared to a mean of only 80% in the coppice (maximum of 87.0%). Secondly, the oil traits of 20 coppice plants from one 12-month harvest rotation to the next were compared. Again, total above ground biomass, foliar oil concentration and cineole proportion were significantly related between the harvests, with cineole proportion having a Pearson's correlation of 0.90 between rotations. The coppice between rotations were remarkably consistent in terms of biomass and oil traits and indeed mean coppice cineole yields were 28.6 and 29.7 g in rotations 1 and 2, respectively. The results support the screening of key oil-related traits in saplings for the selection of elite genotypes for plantations, and the use of short-rotation cultivation of the plantations for continued oil harvesting. Furthermore, no relationship was observed between biomass and oil concentration in the blue mallee saplings or coppice, suggesting selection gains in a given key oil trait will not result in losses in another.     

林木无性繁殖及其在林业生产中的应用进展

在对无性繁殖的特点进行总结的基础上，综述了无性繁殖在无性系林业、林木遗传改良、林木复幼等方面应用的最新进展。     

Genetic diversity and association analyses of fruit traits with microsatellite ISSRs in Sapindus

Sapindus mukorossi Gaertn. and S. delavayi Franchet are among the most valuable species in the genus Sapindus for their commercially exploitable plant oils and chemicals. However, few studies have addressed genetic variation and improvement for either species. We evaluated the genetic diversity of germplasm from selected plus trees within a wide region and established the relationship between fruit traits and molecular markers. An association analysis based on inter-simple sequence repeats(ISSRs)provided a genetic basis for studies of fruit traits. A total of 247 loci were detected by scanning 61 trees of S. mukorossi and S. delavayi using 16 ISSR markers. Genetic diversity parameters were estimated for selected superior trees(or germplasm) and S. mukorossi and S. delavayi were categorized into two main groups, as well as into four groups within S. mukorossi. An association analysis between the ISSR markers and 14 fruit traits used the TASSEL MLM model. A genetic structure analysis differentiated S.mukorossi and S. delavayi. Eighteen ISSR loci associated with 13 fruit traits(P<0.005) were identified, with 13, 1,and 4 loci associated with seed oil production, fruit saponin production, and fruit quality, respectively. Using this information, a core collection was selected with adequate genetic diversity and good seed oil characters. Our results demonstrate the feasibility of effectively estimating fruit trait associations in Sapindus using ISSR markers, and the method is applicable and valuable for select germplasm conservation. The markers obtained in this study are potentially useful for molecular-assisted breeding of Sapindus spp.     

Assessing the utility of ALOS PALSAR and SPOT 4 to predict timber volumes in even-aged Eucalyptus plantations located in Zululand,South Africa

In commercial forestry, regular terrestrial enumerations of the growing stock are required for the valuation, sustain-able management and planning of current and future timber supplies. In this study we examined whether the combination of synthetic aperture radar (ALOS PALSAR) and optical satellite (SPOT 4) image data can accurately predict the timber volume of even-aged Eucalyptus plantations located in South Africa. Results from this study show that the combination of ALOS PALSAR and SPOT 4 produces a R ² value of 0.68 for the planted model, whereas the coppiced model produced a R ² value of 0.55. However, by including stand age as an independent variable in the stepwise model, there was a 15% improvement for the planted model, whereas the coppiced model produced a 27% improvement. The final model developed in this study produced a R ² value of 0.83 and a RMSE of 31.71?m³ ha?1 for planted stands, whereas the model for coppiced stands produced a R ² value of 0.82 and a RMSE of 27.70?m³ ha?1. As it is not practical or financially feasible for commercial forestry companies to carry out terrestrial enumerations for all plantations on an annual basis, the model developed in this study presents an alternative and accurate method to calculate timber volume for even-aged Eucalyptus plantations.     

福建省林业与社会经济发展关系分析

在对福建省林业和社会经济情况进行分析的基础上,利用Matlab统计工具,根据林业和社会经济指标,将福建省9个地级市分别进行聚类,探讨了林业与社会经济之间的相关性,并提出了各地区根据自身特点发展林业的建议。     

不同松树杂种F_1代在浙北和皖南的生长差异及其早期评选

利用4类松树杂种(火炬松×洪都拉斯加勒比松、火炬松×巴哈马加勒比松、湿地松×洪都拉斯加勒比松、湿地松×巴哈马加勒比松)在浙北7 a和6类松树杂种(火炬松×洪都拉斯加勒比松、火炬松×本种加勒比松、火炬松×巴哈马加勒比松、湿地松×洪都拉斯加勒比松、湿地松×本种加勒比松、湿地松×巴哈马加勒比松)在皖南9 a的树高、胸径和材积指标,研究了不同杂种在不同地点的生长表现。结果表明:不同杂种类型在不同地点的生长差异非常显著。在浙北余杭试验点火炬松×洪都拉斯加勒比松生长最好,其中材积增长超过对照40%的杂交组合有PTCH20、PTCH12、PTCH41、PTCH17、PTCH61和PTCH16共6个,全部是火炬松×洪都拉斯加勒比松,占该试验点所有杂交组合的11.11%;在皖南太湖试验点生长较好的杂交组合多为湿地松×古巴本种加勒比松,少量为湿地松×洪都拉斯加勒比松,同时该地区火炬松×洪都拉斯加勒比松杂种也有生长较好的杂交组合,该地区优良杂交组合(材积超过对照40%)包括PECC1-37、PECH12-9、PTCH13-24、PECC18-55、PECH42、PECC18-32、PECC10-6共7个,占所有杂交组合的28%,包括3个杂交组合类型(湿地松×本种加勒比松、火炬松×洪都拉斯加勒比松、湿地松×洪都拉斯加勒比松)。该结论和国内外关于杂种松的适应性及生长优势研究的结论基本一致,对我国南方不同地区发展速生杂种松具有参考意义。     

Estimates of genetic parameters and genetic gains for growth traits of two Eucalyptus urophylla populations in Zululand,South Africa

In South Africa, Eucalyptus urophylla is an important species due to its disease tolerance to fungal diseases such as Crysoporthe austroafricana and the Coniothyrium sp. cankers. It is mainly planted as a parental species in a hybrid combination with E. grandis. Generally, the E. grandis × E. urophylla hybrid has better disease tolerance and higher wood density than pure E. grandis. The current strategy is to maintain large breeding populations of both parental species in order to provide improved elite selections for hybrid crosses on a regular basis. With this in mind, two E. urophylla populations, consisting of five provenance/progeny trials, were established in the subtropical region of Zululand. The aims of this study were, firstly, to determine the magnitude of genotype × environment interaction of E. urophylla in Zululand; secondly, to estimate genetic parameters and correlations for diameter at breast height (DBH), height and volume; and thirdly, to identify selections to advance the current breeding population as well as to hybridise with E. grandis. Results indicated that genotype × environment interaction effects would be practically negligible for growth in Zululand and therefore a single breeding population will be appropriate. In general, all growth traits were under low to moderate genetic control, with narrow-sense heritabilities ranging between 0.14 and 0.48 for volume. The genetic correlations between growth traits were high (0.98 and 0.99 for DBH– volume). This is an indication that DBH is a sufficient growth measure to use in E. urophylla breeding programmes. Best linear unbiased prediction estimates indicated that aa selection scenario of 200 individuals will generate genetic gains of 44.7% over the population mean. The estimated gains for the top 50 individuals that could potentially be used as hybrid parents to cross with E. grandis was 59.8% over the population mean.     

Comparison and early selection of new clones in Populus tomentosa

In our study, two experimental plantations, respectively, with 24 and 32 new clones of P. tomentosa, were established in Weixian County, Hebei Province and Wuzhi County, Henan Province using a completely randomized block design. A comparative study was conducted on the continuous 5-year-old height and diameter at breast height (DBH) of new clones in the two plantations. As well, based on genetic correlation over the years of testing of these clones, a preliminary study of early selection was carried out. Results indicate that the growth traits of the new clones in Weixian were better than those in Wuzhi The traits show weak correlation between the two plantations. In some stands, the height, DBH and seedling volume of 5-year-old clones presented statistically sig-nificant differences among clones. In both plantations, the new clones showed over 0.6 repeatability of beight, DBH and volume, as well as larger coefficients of variation (CV). The fact that these clones achieved the largest repeatability and CV in the second year suggests that these traits are highly controlled by heredity. Thus, based on the growth traits of the second year, the new clones B305, B307, B303, H75, BT18, BTI7 and 21J-1 were considered suitable in Weixian. hi Wuzhi, the new clones had variable repeatability and CVs in various years and their correlation of growth traits among different years was not high. We conclude that early selection of new clones was not feasible in Wuzhi.     

Walnut demonstrates strong genetic variability for adaptive and wood quality traits in a network of juvenile field tests across Europe

Adaptive and wood quality trait data were collected and analyzed on commercially available Juglans regia and J. regia×J. nigra provenances and progenies planted across Europe in a multi-site network. A total of 19 seed sources, replicated 35 times per site, were planted at 13 sites from 5 European countries, encompassing the potential distribution area of timber production plantation sites. The following traits were evaluated: survival, height, diameter at breast height, stem form, apical dominance, vegetative budbreak, along with biotic and abiotic damage. Mean values were significantly different both among provenances/progenies and sites. Most common damage was late spring and early autumn frost. Bud break ranking was significantly correlated with provenance and progeny origin. Although J. regia is fast growing, southern European early budbreak plant material should not be planted under most middle European conditions where late spring frost can be expected, as it has a significant negative impact on architectural (and thus wood quality) traits. Hybrid J. regia×J. nigra progeny performed better than J. regia provenances/progenies for most traits measured. Differences were significantly in favor of hybrids at sites with medium to low fertility, although some locally selected seed sources tended to perform as well as hybrids on high fertility sites.     

黄土高原刺槐人工林根系分布与土壤水分的关系

对黄土高原丘陵沟壑区4种典型立地下刺槐人工林根系分布与土壤水分的关系进行了研究.结果表明:阴坡、半阴坡的细根(直径≤1 mm)在400 cm土层中的分布较为均匀,半阳坡和阳坡的细根集中分布在0~100 cm土层中,在200~400 cm土层中分布较少;各立地输导根(直径>1 mm)在分布深度上存在差异,阴坡和半阴坡输导根分布较深,阳坡输导根分布均较浅,半阳坡分布较阳坡为深;各立地下刺槐根系的水平分布均较广,水平根单向延伸最大均在8 m左右.不同立地条件下土壤水分状况的差异是各立地根系尤其是细根分布差异的主要原因之一;各立地细根分布范围对土壤水分变化有较大影响,同时根系分布也会影响到土壤水分的季节变化.