Geographic variation in tree growth and wood density of <Emphasis Type="Italic">Guazuma crinita</Emphasis> Mart. in the Peruvian Amazon

Guazuma crinita Mart. is a fast-growing timber tree in the Peruvian Amazon. A trial of 11 Peruvian provenances was established in three planting zones. Tree growth at 6, 12, 18 and 30 months and wood density at 32 months were analyzed across and within zones. Zones accounted for more variation than provenances. Density varied significantly due to provenances in the analysis across zones, whereas growth exhibited strong provenance by zone interactions. The local provenance grew well and produced relatively dense wood in all zones. The relative magnitude of variation due to provenances depended on the planting zone. Density was greater in the lower than in the upper stem. Density increased with longitude from the more humid to the drier part of the sample region. In general, correlations indicated that larger trees had lower density and a larger difference in density between the lower and upper stem, but the strength of these relationships depended on the provenance and zone. Results suggest that fast-growing provenances can be selected at an early age without significantly reducing wood density. The local provenance is recommended for reforestation pending future research demonstrating the superiority of foreign provenances. Some practical implications for tree-improvement programs are discussed.     

Genetic variation in seed and seedling traits in 12 African provenances of Faidherbia albida (del.) A. Chev. at Lodwar, Kenya

The extent of genetic variation in seed length, width, thickness, weight and germination percentage and seedling traits among and within 12 African provenances of Faidherbia albida was examined. The regional provenances showed a consistent variation in seed length, seed width and seed weight: the southern African provenances had the largest seeds and west African provenances the smallest. Seedling height, stem collar diameter and true leaf number differed (P = 0.05) among the provenances 90 days after germination. The seedlings from west Africa were shorter, had smaller stem collar diameter and fewer leaves. In contrast, the southern and east African provenances had taller seedlings with bigger seedling diameter and more leaves per seedling. Seedling traits did not show clear-cut divisions between southern and east African provenances, but the west African provenances formed a distinct group. Positive correlations were found in some of the seed characteristics and seedling height among provenances, which could be an important criterion for early provenance selection. Greater variation was observed for seed and seedling traits among than within provenances suggesting that selection among provenances might result in rapid genetic gain for the traits studied. This revised version was published online in June 2006 with corrections to the Cover Date.     

枫香地理种源变异与选择

对我国15个枫香地理种源的4.5 a生幼林树高、胸径和冠幅等生长性状进行测定。通过方差分析、相关分析和遗传力参数等的估算结果表明:各地理种源间树高、胸径和冠幅差异极为显著,且树高和胸径有较高的广义遗传力,受中等强度遗传控制。树高、胸径与各种源的地理位置不相关,冠幅与纬度呈显著正相关。采用聚类分析,可以划分为4个种源区。根据枫香幼林生长表现,南部种源区表现最差,以中部种源区的湖南桑梓和东部种源区的江西湖城表现最好。     

乐东拟单性木兰地理种源变异与选择研究

对乐东拟单性木兰14个种源种子、苗期以及幼林期生长性状进行了调查分析.结果表明:种子千粒质量、苗高、地径、叶长和叶宽等5个性状在种源间差异极显著;造林保存率种源间差异显著,来自北部的种源,如浙江龙泉种源保存率较高,而来自南部的海南尖峰岭种源保存率较低;幼林期4年生树高、5年生树高和胸径、6年生树高和胸径等5个主要生长性状种源间差异均达到极显著水平,其生长性状广义遗传力为0.855～0.930,说明乐东拟单性木兰幼林期主要生长性状的表型差异主要受遗传因素的控制;乐东拟单性木兰苗高和地径与纬度负相关,表明随种源纬度的升高,乐东拟单性木兰种源苗期生长有减小趋势;乐东拟单性木兰幼林期树高和胸径与经度正相关,与纬度极显著正相关.根据乐东拟单性木兰种源幼林期试验结果,选择出浙江龙泉、福建顺昌和湖南新宁3个优良种源.通过聚类分析,把乐东拟单性木兰种源初步划分为3个区:西部种源区、东部种源区和南部种源区.     

Correlations and clines in tree growth and wood density of <Emphasis Type="Italic">Balanites aegyptiaca</Emphasis> (L.) Delile provenances in Niger

Balanites aegyptiaca (L.) Delile provides wood and other essential products for farming and pastoralist communities in the West African Sahel. In this region, mean annual rainfall decreases in general from south to north and from west to east, so one might expect clinal variation in fitness-related traits in relation to the rainfall gradients. This paper presents results from a provenance/progeny test of 11 provenances sampled in Niger and established at one relatively dry site in Niger. The objectives were to evaluate phenotypic correlations (Pearson r) between tree growth (height, stem diameter) and basic density of the wood, and clines in growth and density at 13 years. Tree growth and wood density were positively correlated, and the correlations differed among provenances. Mean tree height and stem diameter of provenances increased, in general, from the more humid to the drier parts of the sample region. Results suggest that selection of faster-growing trees could lead to an increase in wood volume and density in the subsequent generation, especially in certain provenances; that provenances from drier areas are better adapted to drought; and that tree improvement and conservation programs should collect seeds from populations in the drier areas for planting and conservation.     

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.     

Trait variations in 28-year-old teak (Tectona grandis) provenance field trials in Ghana,West Africa

Stem straightness, axis persistence, presence/absence of protuberant buds and epicormics, diameter and height have profound influence on timber quality and volume of teak (Tectona grandis). Provenance trials of teak were established in the 1970s in Ghana, as part of the Food and Agriculture Organization (FAO) International Series of Provenance Trials, with the view of selecting teak germplasm for sites with specific environmental conditions. Two field trials were located in dry semi-deciduous (dry) and moist semi-deciduous (moist) ecological zones of Ghana. They consisted of 13 provenances, including four landraces each from Ghana and Indonesia, and two and three provenances from India and Laos, respectively. Trees were assessed at 9, 17 and 28 years to (1) quantify the potential variation in quality and timber volume production, (2) examine possibilities for determining early selection of parameters of superior provenances and (3) select provenances for sites with particular environmental conditions. Production traits were higher on the moist site than the dry site. Mean height was 23.2 and 20.2 m tree^?1, stem cross-sectional area at breast height was 0.0896 and 0.0474 m² tree^?1, and stem volume was 0.75 and 0.34 m³ tree^?1 for the moist and dry sites, respectively. Nilambur provenance from moist India had the highest mean stem straightness score of 19% above average, whereas Savannakhet from Laos had the best protuberant bud score with 18% of the trees above average. Indonesian landraces performed better in the dry zone, whereas provenances from India and Laos performed better in the moist zone. Phenotypic correlations between age 9 and 28 years were moderate (r 0.54–0.90) to high (r > 0.90) for production and qualitative characteristics, indicating feasibility of early assessment for identification of superior provenances. Nilambur and Savannakhet II provenances proved to be favourable choices for the moist zone, whereas the Temandsang provenance from Indonesia was found to be the best choice for the dry site.     

2年生乐昌含笑种源生长研究

来自4个省（区）的14个乐昌含笑种源在广东开展了多点种源试验,1-2年生测定结果表明：树高、地径在不同种源和不同地点间生长差异均达到显著水平,而种源与地点交互作用不显著,两个性状的遗传力均在0.7以上;各调查性状间的遗传相关性非常密切,多数性状间的表型相关性达到极显著或显著水平;树高、地径生长均表现良好的种源为4和13号,速生稳定性最好的种源为13号;选择13号种源（即仁化长江种源）,可以得到3.97%的树高增益和8.81%的地径增益,早期遗传改良效果较明显。     

不同种源枫香幼龄林生长性状及物候节律研究

通过对我国10个枫香地理种源6 a生幼龄林树高、胸径和材积等生长性状以及物候节律进行观测。结果表明:不同种源间树高、胸径和材积均达到极显著差异水平,且两两生长性状均呈现极显著正相关,在武汉市九峰试验林场生长的优势的种源有‘江苏南京’和‘云南富宁’,而生长最差的种源是‘河南南阳’和‘河南商城’。枫香树高分别与经度和年降水量呈现显著正相关,且胸径和材积与年降水量呈显著正相关。不同种源枫香的萌动期、绽叶期、展叶期和落叶期等存在显著差异,处于低纬度的‘广西岑溪’和‘云南富宁’种源的萌动期、绽叶期、展叶始期、展叶盛期、落叶始期均较其他高纬度种源早,而落叶盛期和落叶末期又较其滞后。     

巨桉种源家系多点遗传变异及选择比较

对4．5 a 生巨桉种源／家系3个试验点共13个种源175个家系的生长和形质性状进行遗传分析。结果表明：所有观测性状在地点、区组和家系间均呈极显著差异（P ＜0．01）,胸径在种源间差异极显著（P ＜0．01）,树高、干形、分枝和冠幅在种源间差异不显著;树高和胸径变异系数在地点间差异不大,冠幅表型变异系数为45％～60％,江西南康的分枝变异系数高达34％,广东连山的分枝变异系数仅15％,总体上广东连山试验点各性状变异系数略低于江西南康和云南景谷,冠幅遗传变异系数＞胸径＞树高＞干形＞分枝,景谷点参试性状遗传力＞连山点＞南康点;相关性分析表明：生长性状间、生长性状与冠幅、生长性状与部分形质指标均呈极显著正相关（P ＜0．01）;利用综合指数选择法,筛选1号（昆士兰州 NW Townsille）、2号（昆士兰州 Copperlode）和12号（四川乐山）为优良种源,2号（昆士兰州 Copperlode）、21号（昆士兰州 Barron Gorge National Park）、40号（昆士兰州 Koombooloomba）、51号（昆士兰州 Tinaroo）、125号（昆士兰州 Bambaroo）、127号（昆士兰州 Bambaroo）、137号（昆士兰州 Bambaroo）和144号（昆士兰州Tully Gorge National Park）等家系在两个试验点中同时表现优良,但没有家系同时在3个试验点中表现突出。     

不同种源香椿苗期生长差异比较

采用14个产地种子所育的1 a生香椿播种苗为测定材料,研究了各种源苗期生长差异,发现各种源香椿苗的苗高、地径与生物量等生长性状均存在显著差异,同一种源内不同单株之间也存在较大差异.7～9月是香椿苗高生长的主要时期.香椿种源的地理变异规律主要表现为南一北变异趋势.综合其生长表现,初步选出江苏南京和湖南洞口2个种源为苗期优良种源.     

西南桦在广东省中部引种初报

西南桦是我国热带、南亚热带地区的优良乡土阔叶树种。文章对广西壮族自治区11个西南桦种源在广东省中部引种的苗期及幼林生长性状进行了分析,结果表明:引种西南桦的地径、苗高以及幼树高生长在种源间、家系间差异极显著,种源内遗传变异大于种源间,家系遗传力高于种源。依据苗期地径选择出表现良好的5个种源,在其中选择出35个优良家系,遗传增益为14.59%;根据苗高在5个优良种源中选择20个优良家系,遗传增益达到21.27%。幼林阶段高生长与苗期略有变化,根据幼树高生长指标在5个优良种源中进一步选出25个优良家系,遗传增益达到10.03%。     

木荷种源苗期干物质积累和分配差异

利用28个木荷种源的苗期测定材料,研究了不同种源的干物质积累和分配规律。结果显示:木荷苗期单株及其根、茎、叶各器官的干物质积累量在不同种源区间和种源区内不同种源间存在显著的遗传变异,这种变异主要来源于种源区内种源间,其次是来源于不同种源区间。木荷苗期单株及各器官的干物质积累量呈典型的纬向渐变模式,即南部种源区>中部种源区>北缘种源区,而与经度的相关性较小。研究发现,不同种源区间木荷干物质积累量在地下和地上部分的分配比例(即根冠比)遗传分化较小,变异主要来源于种源区内种源间,木荷种源根冠比表现为随机变异的地理模式,自然分布区内降雨量丰富,较少干旱胁迫可能是其主要的原因之一。     

木荷地理遗传变异和优良种源初选

在2005年底,对福建建瓯、浙江淳安和庆元的3年生37个产地的木荷种源试验林进行了全面调查,系统研究了幼林生长和分枝性状的种源差异、种源与环境互作及地理变异模式.结果表明:木荷树高、当年抽梢长度、地径、冠幅及侧枝总数、侧枝长和侧枝粗等分枝性状都存在显著的种源效应,木荷地理种源分化明显.造林区立地生境和造林地立地条件对木荷种源生长影响显著,如福建建瓯点3年生种源平均树高较北缘区浙江淳安点和高海拔山地浙江庆元点分别提高了24.1%和18.0%.木荷树高、当年抽梢长度、冠幅、侧枝总数等存在显著的种源×地点和种源×重复/地点互作,不同种源在各区试点上的生长相对表现差异显著.相关分析表明,木荷生长和分枝性状的地理变异模式因区试点环境条件差异而迥异.在中心分布区的福建建瓯点,种源生长和分枝性状与产地纬度相关性显著,呈典型的纬向地理变异模式,速生种源主要来源于分布区的中南部;在北缘区的浙江淳安点,种源高径生长与产地经纬度相关性较小,仅发现侧枝总数和树冠浓密度与产地纬度呈一定程度的负相关,速生种源主要来源于分布区的中部;而在较高海拔区的浙江庆元点,由于环境相对恶劣,木荷种源生长和分枝性状与产地纬度呈显著的正相关,偏北部种源的早期生长表现较好.基于种源幼林测定结果,分别从中心分布区和北缘区初选了一批速生用材和生物防火优良种源.     

湿地松种源试验初报

通过对福建南屿湿地松种源苗期和14 a生的林分试验结果进行分析,结果表明:湿地松种源种子千粒重、发芽率、成活率差异大,种源间苗高差异显著,地径差异不显著。14 a生湿地松各种源间树高、胸径和材积种源间有一定差异。湿地松种源1 a生苗高与年降雨量呈显著的负相关,14 a生树高与纬度呈显著的负相关,与年降雨量和无霜期呈较大的正相关,说明低纬度区引种湿地松,年降雨量大和无霜期长可显著促进其树高生长。14 a生湿地松各种源生长量均超过火炬松和当地马尾松。     

Ten-year results from red alder (<Emphasis Type="Italic">Alnus rubra</Emphasis> Bong.) provenance-progeny testing and their implications for genetic improvement

Ten-year data on growth and survival of two red alder provenance-progeny test trials located in the southern and northern coastal regions in British Columbia, Canada, were analysed and their implications for the genetic improvement of this species were discussed. A total of 42 and 41 provenances, each represented by two to five open-pollinated families were evaluated at each site, respectively. Results indicate that red alder provenances responded differently to the environmental conditions of the two sites. At age 10, red alder provenances tended to perform better at sites near their origin. The results support earlier work that two breeding zones should be delineated with the boundary at approximately 52° N. One may expect an average of about 5% decrease in stem volume and 6% increase in mortality, respectively, for each degree of southward and northward transfer of seed sources from their origins. Individual, family, and within-family heritabilities for height, diameter, stem volume were moderately high (0.22–0.42), for the southern zone, implying good potential for genetic improvement. Heritabilities were somewhat lower (0.12–0.39) for the northern zone because of greater environmental heterogeneity of the test site. Selecting the top 20 unrelated individuals for seed orchard establishment would result in 29% and 23% gain in stem volume at a rotation age of 40 years in the southern and northern zones, respectively. Correlation between ranks of the predicted breeding values for height at different ages and stem volume at age 10 increased rapidly when plantation was young and became relatively stable after 6 years of out-planting. Stem volume had much stronger correlation with diameter (≥0.84) than with height (≤0.67). Early selection at age 6 based on stem volume is therefore recommended.     

Variation in seed traits and seedling vigour of Cordia africana Lam.provenances in Ethiopia

Cordia africana is a very important indigenous tree species for timber and other products and services in Ethiopia.Seed traits and seedling vigour of seeds from 12 provenances of the species were compared.Mean seed mass for each provenance was assessed for 1000 seeds in10 replications,and seed length and width were measured for 100 seeds in four replications per provenance.Germination was assessed in a glasshouse taking 400 seeds from each provenance.Root collar diameter and height of 440 seedlings grown in a nursery for 290 days in Addis Ababa were measured.Seed length,seed width,seed mass,and shoot height and root collar diameter of seedlings showed significant differences(P0.001) among provenances.Correlation analysis between seed and seedling traits and environmental variables revealed significant positive correlations between seed width and germination percentage,seed width and altitude,seed width and longitude and seed length and latitude.Negative correlations were obtained between seed width and temperature,seed width and rainfall,seed mass and temperature,and germination and temperature of the seed source.As expected,differences in seed trait did not explain the variability in seedling vigour.Determining quantitative variations in seed traits and seedling vigour among provenances and the patterns along environmental gradients are essential for informing decisions on the tree improvement programme of the species.     

Provenance-specific growth responses to drought and air warming in three European oak species (Quercus robur, Q. petraea and Q. pubescens)

Provenance-specific growth responses to experimentally applied drought and air warming were studied in saplings of three European oak species: Quercus robur, Quercus petraea and Quercus pubescens. Four provenances of each species were grown in large open-top chambers and subjected to four climates: control, periodic drought, air warming or their combination in 3 subsequent years. Overall growth responses were found among species and provenances, with drought reducing shoot height growth and stem diameter growth and air warming stimulating shoot height growth but reducing stem diameter growth and root length growth. Differential growth responses in shoots, stems and roots resulted in altered allometric growth relations. Root length growth to shoot height growth increased in response to drought but decreased in response to air warming. Stem diameter growth to shoot height growth decreased in response to air warming. The growth responses in shoots and stems were highly variable among provenances indicating provenance-specific sensitivity to drought and air warming, but this response variability did not reflect local adaptation to climate conditions of provenance origin. Shoot height growth was found to be more sensitive to drought in provenances from northern latitudes than in provenances from southern latitudes, suggesting that genetic factors related to the postglacial immigration history of European oaks might have interfered with selective pressure at provenance origins.     

闽楠种源苗期生长性状地理变异研究

为研究不同产地闽楠（Phoebe bournei）幼苗生长性状的变异规律及其与地理、气候因子的关系,以来源于6个省区的12个种源的种子培育的幼苗为试验材料。研究分析了闽楠幼苗苗高、地径、生物量等性状的种源差异,苗期生长性状与种源产地气候或与地理因子间的相关性以及各性状的相关性。结果表明：参试种源间生长差异显著,这些差异主要由遗传因素制约;地径、地下生物量与经度呈显著负相关关系,地径与海拔呈显著正相关关系;各观测性状与无霜期呈显著或极显著相关关系;苗木苗高、地径、生物量等性状之间呈显著或极显著相关关系。根据聚类分析结果,供试的12个种源可划分为优、良、中、差4类,其中广西、贵州种源具有较明显的生长优势。综合分析结果表显示：闽楠各种源间存在明显的遗传分化,地理隔离导致幼苗的生长性状变异丰富,西南地区种源普遍生长较好。     

不同种源无患子苗期生长性状遗传变异研究

利用9个种源90个家系的无患子(Sapindus mukorossi)种子在浙江省杭州市余杭长乐林场进行苗期试验,结果表明,无患子1年生苗生长期可分为生长初期、速生期和木质化期,地径生长高峰期晚于苗高生长高峰期。方差分析表明,不同种源、不同生长时期苗高和地径生长性状差异较大,呈极显著水平。相关性分析显示,苗高生长性状与种源地纬度呈显著性负相关,南部种源苗期生长性状明显好于北部种源,初步选择出江西上犹、浙江龙泉、江西宜丰3个优良种源,上犹7号、上犹8号、上犹9号、宜丰1号、宜丰6号、龙泉4号和龙泉10号共计7个优良家系。