Single-tree Plots Research Articles

Genetic Parameters for Bud Flushing and Growth Characteristics of White Spruce Seedlings

Abstract We estimated heritabilities and correlations for bud flushing and growth traits of white spruce seedlings, and the correlations of seedling traits with 10- and 11- year height of the same families in the field. The seedling greenhouse experiment had a randomized complete block design with 30 replications, 58 open-pollinated families and single-tree plots. Individual tree heritability (hi 2) was 0.78 and 0.54 for 18 (H18) and 36 (H36)-week total height, respectively. The corresponding heritabilities for family means (hf 2) were 0.91 and 0.82. For root collar diameter, hi 2 were respectively, 0.61 and 0.22 at 24 and 54 weeks from germination. The corresponding hf 2 were 0.87 and 0.55. Heritability for bud flushing ranged from 0.13 to 0.46 (hi 2) and 0.44 to 0.83 (hf 2). The genetic correlation (ra) between H18 and H36 was 0.70 and that of D24 and D54 was 0.89, indicating a substantial change in family ranking in one growing season. The type B genetic correlation for H18 with field heights ranged from 0.22 to 0.30. Type B genetic correlations of field height with all other seedling traits were very low and largely negative. It can be concluded that: (1) age-age correlation of seedling height can be expected to decline drastically even in a stable environment of the greenhouse, (2) heritability for growth potential is meaningful when estimated on cumulative growth not on individual annual growth increments that are susceptible to short-term environmental variation, (3) dates of bud flushing did not influence variation in height and root collar diameter, and (4) field growth potential is better predicted by greenhouse growth potential than other morphological and shoot phenological traits.

On-farm selection for quality and resistance to pest/diseases of cocoa in Sulawesi: (ii) quality and performance of selections against Phytophthora pod rot and vascular-streak dieback

The cocoa industry in Sulawesi, the main region of cocoa production in Indonesia, is threatened by destructive diseases, including vascular-streak dieback (VSD) caused by the basidiomycete Oncobasidium theobromae and stem canker and Phytophthora pod rot (PPR) or black pod, caused by Phytophthora palmivora. Using the considerable genetic diversity of cocoa on farms, host resistance was identified and tested with the participation of farmers. Forty-nine local and international cocoa selections with promising resistance characteristics (as well as susceptible controls) were side-grafted onto mature cocoa in a replicated trial with single-tree plots. Developing grafts were assessed in the dry season for severity of VSD infection, scored from 0 (no infection) to 4 (graft death). All of the 49 clones in the trial became infected with VSD in at least some replicates. Average severity varied from 0.2 to 1.6. Potential VSD-resistance was found in eight clones, including DRC 15, KA2 106 and a local Sulawesi selection, VSD2Ldg. Some of the most susceptible clones were local Sulawesi selections from areas with a history of little or no VSD. Thirty-four pod-bearing clones were evaluated over a 2-year period for yield, quality and resistance to natural infections of PPR. Cumulative PPR incidence for all clones was 22% but varied from 8.6 to 43% among clones. Clones with less than 15% PPR incidence were designated as resistant, including DRC 16 and local Sulawesi selections, Aryadi 1, Aryadi 3 and VSD1Ldg. Scavina 12 was moderately resistant in the trial with a PPR incidence of 23%. Cumulative incidences of the mirid, Helopeltis spp., determined in the same evaluation period, indicated that DRC16 was the most susceptible clone with an incidence of 52% in ripe pods and 23% in immature pods. In comparison, KKM4 showed evidence of resistance to Helopeltis spp., with incidences of 34 and 0.8% in ripe and immature pods, respectively. The impact of diseases and pests (including cocoa pod borer) on bean losses and bean quality varied between clones but generally the bean size (or bean count) was affected more than the fat content or shell content.

Assessing longleaf pine (Pinus palustris) restoration after southern pine beetle kill using a compact experimental design

A compact experimental design and analysis is presented of longleaf pine (Pinus palustris) survival and growth in a restoration project in the Piedmont region of Georgia, USA. Longleaf pine seedlings were planted after salvage logging and broadcast burning in areas of catastrophic southern pine beetle (Dendroctonus frontalis) attacks on even-aged mixed pine–hardwood forests. The split-plot design with randomized complete blocks was replicated on four sites. Main treatments were: chemical control of competing vegetation with herbicides; mechanical mowing to remove above-ground competition; and an untreated control. Nested within fixed-area treatment plots were single-tree plots centered on longleaf pine seedlings where adjacent vegetation was assessed immediately before treatment in years 1 and 2. Treatments applied to single-tree plots comprised three sizes of sprayed area around seedlings in chemical treatment plots. Logistic mixed-effects models indicated that initial survival was impacted by herbaceous vegetation but remained unaffected by the various vegetation control treatments applied later in year 1. Control of above- and below-ground competition around planted seedlings by mowing in conjunction with herbicide treatments resulted in significantly greater frequency of emergence from the grass stage, accelerating development of longleaf pine planted to restore beetle-killed areas in the Piedmont region of Georgia.

EVALUATION OF SELECTED EUROPEAN CHESTNUT (CASTANEA SATIVA) PROVENANCES - I: INTER-PROVENANCE GENETIC VARIATION

The performance and variability of 143 open-pollinated families of Castanea sativa from six natural contrasting European chestnut populations were investigated. After four years of out-planting, growth and morphological traits were studied for three consecutive years at the Taxiarchis provenance-progeny trial located in Greece. The experimental design was a complete randomized block design with single-tree plots with 3 x 3 m spacing in 10 replicates. Notable variation was revealed both among and within families for height, diameter, index volume and number of leaves. Age x family interaction was not significant indicating some families were stable in their ranking at different ages, suggesting that early selection between families may be effective. No particular trend could be associated with an age regarding estimates of the coefficient of variation (CV A ) and individual, family and within family heritabilities. The genotypic variance components accounted for up to 8.1% for diameter, 8.5% for height, 7.5% for volume and 5.2% for number of leaves. Four selection methods: individual, family, within family, and combined were used to estimate genetic gain. It reached 25% for diameter, 28% for height, 68% for volume and 49% for number of leaves, in a scheme of 10% selection across selection methods and ages. Combined selection for volume consistently had the highest genetic gain.

A New Breeding Strategy for Pinus radiata in New Zealand and New South Wales

AbstractA new breeding strategy is presented for the Radiata Pine Breeding Company, a New Zealand based research consortium, that drives the breeding program for Pinus radiata for both the New Zealand and New South Wales based Australian forest plantation industry. The new strategy builds on the existing base for P. radiata, and on the last strategy review in 2000. The new strategy comprises a large open-pollinated (OP) Main Population (MP) with 500 female parents and two sublines (250 female parents per subline). The MP will be tested using alpha designs, single-tree plots and incomplete blocks to maximise efficiency. Each subline will be tested on four sites, geographically distant from the other subline. The MP will be managed in discrete generations. Selection of the next generation will be using a combination of backward and forward selection, but the strict control of inbreeding with identified lineage will rely on the development of parental reconstruction for OP progeny. There are alternatives to this, however, such as estimating the group coancestry and accepting some additional increase in inbreeding. This is a new and significant departure from previous breeding strategies for P. radiata in New Zealand. There will also be a single, small Elite Population (EP), tested 50% as progeny and 50% as clones. Twenty four parents will be tested each year as clones and 24 as seedling progeny with some overlap between the two. It is expected that the clonal population will capture the greatest gains in traits with low heritabilities, and the half-sib progeny will capture the greatest gains in traits with high heritabilities. The two sublines will be maintained in the EP, and breeding will be managed as a rolling front with trials established every year, while trials of the MP will be established every 10 years.

Performance and Genetic Parameters of Somatic and Zygotic Progenies of Coastal Douglas-fir at 71/2-Years across Washington and Oregon, USA

Abstract Five genetic tests involving 37 somatic clones of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) were planted March 2000 in Weyerhaeuser plantations across western Washington and Oregon States, USA. Four of the tests are in Longview, Twin Harbors and Vail regions of Washington, and one test is in Springfield, Oregon. Each test is based on single-tree plots with 12 randomized complete-blocks. The 37 coastal Douglas-fir clones were propagated by somatic embryogenesis from four full-sib families. Zygotic seedlings from two of these full-sib families were planted across all five tests to allow comparison between somatic and zygotic trees of the same pedigree. Results are reported for survival, stem height, diameter at breast-height (DBH), volume and stem sinuosity at 71/2- years. On average the total population of 37 somatic clones had less stem sinuosity, but grew more slowly than zygotic trees across the five tests studied. However, the best 20% of somatic clones for growth produced 25% greater stem volume at 71/2-years than the zygotic fullsib families. Height had a clonal heritability of 0.61 ± 0.09, DBH 0.64 ± 0.06, volume 0.58 ± 0.08 and stem sinuosity 0.26 ± 0.06. The clonal genetic correlation between height and DBH at 71/2-years was 0.98 ± 0.01, while stem sinuosity was adversely genetically correlated with growth. Clonal performance for growth and stem sinuosity was stable across tests with overall between-test correlations of 0.96 to 0.98. This clonal stability resulted in little variance due to clone x test interactions.

Influência do modelo de análise estatística e da forma das parcelas experimentais na seleção de clones de Eucalyptus spp.

Foram avaliadas três formas de parcelas experimentais (retangular, uma linha - linear e parcela de uma árvore - STP) em testes clonais de Eucalyptus spp, utilizando-se três experimentos, cada um com 18 clones. Foram usados três modelos de análise (mínimos quadrados ordinários - ANOVA tradicional, modelos mistos com fator clone fixo ou com fator clone aleatório - REML/BLUP). Os dois primeiros modelos apresentaram resultados similares. Com REML/BLUP houve estreitamento das predições em relação às amplitudes obtidas com as médias, e essa redução foi proporcionalmente maior com parcelas retangulares e STP. O ordenamento dos clones também foi similar com esses dois tipos de parcelas. É provável que com parcelas STP haja um balanço compensatório das alocompetições, pois se pode trabalhar com maior número de repetições e menor custo. Portanto, com parcelas STP haverá economia de recursos e sem prejuízos para o Programa de Melhoramento Florestal.

Genetic Parameters of Somatic Clones of Coastal Douglas-fir at 5½-Years across Washington and Oregon, USA

Abstract Five genetic tests involving 70 somatic clones of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) were planted March-April 1999 in Weyerhaeuser plantations across western Washington and Oregon states, USA. Four of the tests are in Longview and Twin Harbors regions of Washington, and one test is in Springfield, Oregon. Each test is based on single-tree plots with 12 randomized complete-blocks. The 70 coastal Douglas-fir clones were propagated by somatic embryogenesis from two full-sib families that had the same female parent. Results are reported for survival, height, diameter at breast-height (DBH) and volume growth at 5½-years. These tests provide evidence of acceptable growth and survival of somatic trees of coastal Douglas-fir across a range of site conditions. Height had a clonal heritability of 0.25 ± 0.01, DBH 0.21 ± 0.01 and volume 0.20 ± 0.01. The growth traits were all strongly genetically associated with clonal correlations of 0.92 to 0.99. Clonal performance for growth proved quite stable across tests with an overall between-test correlation of 0.84 ± 0.04. There was little variance due to clone x test interactions.

Direct and Competition Additive Effects in Tree Breeding: Bayesian Estimation From an Individual Tree Mixed Model

Abstract An individual tree model with additive direct and competition effects is introduced to account for competitive effects in forest genetics evaluation. The mixed linear model includes fixed effects as well as direct and competition breeding values plus permanent environmental effects. Competition effects, either additive or environmental, are identified in the phenotype of a competitor tree by means of ‘intensity of competition’ elements (IC), which are non-zero elements of the incidence matrix of the additive competition effects. The ICs are inverse function of the distance and the number of competing individuals, either row-column wise or diagonally. The ICs allow standardization of the variance of competition effects in the phenotypic variance of any individual tree, so that the model accounts for unequal number of neighbors. Expressions are obtained for the bias in estimating additive variance using the covariance between half-sibs, when ignoring competition effects for row-plot designs and for single-tree plot designs. A data set of loblolly pines on growth at breast height is used to estimate the additive variances of direct and competition effects, the covariance between both effects, and the variance of permanent environmental effects using a Bayesian method via Gibbs sampling and Restricted Maximum Likelihood procedures (REML) via the Expectation- Maximization (EM) algorithm. No problem of convergence was detected with the model and ICs used when compared to what has been reported in the animal breeding literature for such models. Posterior means (standard error) of the estimated parameters were σ̂2 Ad = 12.553 (1.447), σ̂2 Ac = 1.259 (0.259), σ̂AdAc = -3.126 (0.492), σ̂2 p = 1.186 (0.289), and σ̂2 e = 5.819 (1.07). Leaving permanent environmental competition effects out of the model may bias the predictions of direct breeding values. Results suggest that selection for increasing direct growth while keeping a low level of competition is feasible.

Field performance of ten clones and two sizes of planting stock of Populus deltoides on the Indo-gangetic plains of India

A study was conducted from 1996 to 2001 on well drained sandy loam soils in the central plain region of Punjab to determine the effect of initial size of planting stock and clones of poplar (Populus deltoides) on their height, diameter and volume growth. Two categories of planting stock viz. large size (height >4.7 m and collar diameter >4.2 cm) and small size (height 2.5–4.3 m and collar diameter 2.5–4.0 cm) of ten poplar clones were used for the experiment using a completely randomized design with single tree plots and ten replications. The large sized stock attained significantly greater diameter and volume growth at all ages than those of small size, whereas, the superiority of the former in plant height was only up to 3 years of age. The respective differences for diameter and volume between the stock sizes decreased from 11.7 and 27.96% at 3 years to 4.9 and 11.42% at 5 years of age. Significant differences were observed among clones for all the growth parameters. Clones G-48, 3167, WSL-31 and WSL-38 exhibited the highest growth.

Phosphorus Additions Increase the Early Growth of Red Alder (Alnus rubra Bong.) on Vancouver Island

Abstract The effects of nutrient additions on growth of the red alder (Alnus rubra Bong.) are not well known. We examined the growth and nutritional responses of 10 young (0–4 years old at time of fertilization) red alder plantations on eastern Vancouver Island to additions of phosphorus (P), added as triple super phosphate, and a blended fertilizer (F) containing elements other than nitrogen (N), P, and calcium (Ca). Site fertility classes ranged from poor to very rich and soil moisture regime classes ranged from moderately dry to very moist. Nutrients were added in single-tree plots and responses were measured for up to 3 years after fertilization. In plantations fertilized within 1 year of planting, P additions increased heights (average of 17%), basal diameters (28%), and stem volumes (68%) over a 3-year period and increased 1st-year foliar concentrations of P, N, and S. The fertilizer supplying other elements also increased concentrations of N and S, along with potassium (K), boron (B), zinc (Zn), and manganese (Mn), but increased volume by only 16%. These data suggest that deficiencies of P are more likely to limit the growth of young red alder than are deficiencies of other elements. Older plantations (more than 2 years postplanting) were less responsive to fertilization than were younger plantations (less than 2 years postplanting). Growth of young red alder appears limited by P availability when soil Bray-P and foliar P concentrations are less than approximately 12 mg kg−1 and 2 g kg−1, respectively.

Characteristics and development of improved Pinus sylvestris in northern Sweden

Genetic differences are described between improved and unimproved Scots pine (Pinus sylvestris L.) in 36 northern Swedish field tests, covering wide geographical and climatic gradients (latitude 62.3°–67.8°N). Improved trees were represented by progenies from controlled crosses of first-generation, phenotypically selected plus trees, whereas unimproved trees originated from unselected natural stands. Improved trees were superior in terms of height (9.2%), stem diameter (5.4%), and stem volume (18.9%) at the age of 27.4 years. The height growth of improved trees from ages of 10.5 years to 27.4 years was similar to that of unimproved trees at a site with a higher site index. Improved trees had a 5.5% greater height/diameter ratio (i.e., were more slender) than unimproved trees, whereas differences between the tree categories in terms of survival and frequencies of ramicorns and stem breaks were minor and mostly insignificant. Little or no interaction between tree categories and site conditions for growth characters was found, implying that the results are generally applicable. No difference in response to competition between the improved and unimproved trees was detected. However, differences in their reactions to transfer were found: survival rates increased more and height growth decreased less in improved trees than in unimproved trees when grown at a site south of their geographical origin. The use of competition and height indices based on neighbouring trees to adjust for bias and site variability in single-tree plots significantly improved the estimates.

Accuracy of Ranking Individuals in Field Tests of Different Designs: A Computer Simulation

Abstract A computer simulation was conducted to investigate the accuracy of ranking individual trees in field tests of different designs. A test population that consists of 900 trees from 45 full-sib families generated by three 6-parent disconnected half-diallels was considered. One incomplete block design with single-tree plots and four complete block designs with 1, 2, 4, and 10-tree row plots were examined. Various narrow-sense heritabilities, site variation patterns (patch sizes and gradient slopes), and two levels of dominant to additive genetic variance ratios (0 and 0.30) were evaluated. Results indicate that the accuracy of ranking depends more on the heritability of the trait and less on the magnitude of the dominant genetic variance, site variation patterns, and field designs. With patchy site variation, differences in ranking accuracy were observed for different designs, but became smaller with higher heritabilities. Impact of environmental gradient on the accuracy of individual ranking was negligible. Incomplete block design with single-tree plots (ICB1) provided the most accurate ranking when heritability was low while complete block design with 2-tree plots (RCB2) appeared to be the best when heritability was high. Large row plot designs were among the least effective in all the simulated scenarios. For traits with medium heritabilities, the statistical efficiencies of ICB1 and RCB with 1 and 2-tree plots are comparable.

Comparison Between Open Pollinated Progenies and Hybrids Performance in Eucalyptus grandis and Eucalyptus urophylla

Summary The cellulose industry in Brazil uses, mainly, hybrids between Eucalyptus grandis × E. urophylla. Not only the volume but also the wood density has great influence in the cellulose productivity, therefore a selection for both characteristics should be done as an alternative to increase the improvement program efficiency. The present work has been carried out with the objective of comparison between Open Pollinated progenies (OP) and hybrids performance in E. grandis and E. urophylla. To do so, 15 OP progenies of E. grandis, 15 OP progenies of E. urophylla, and 15 hybrids between E. grandis × E. urophylla, plus four controls were evaluated. The experiment was carried out from October to November 2001, in three sites, Aracruz and São Mateus, in the Espírito Santo State, and Caravelas, Bahia State, Brazil, in a 14 × 14 lattice design, involving the 49 treatments mentioned plus other progenies not considered in this article, with single tree plots and 40 replicates. Two years later the circumference at breast height (CBH) and the basic wood density (BWD) were evaluated. The hybrids performance for CBH was higher, an average, 38,7% than the OP progenies for both species. Part of the heterosis in relation to parental means could be attributed to the inbreeding depression due to selfing that occurred in the OP progenies and the dominance controlling this character. For the BWD the hybrids performance was the same of the OP progenies. Since there was divergence between the parents, it can be inferred that dominance has no importance for this trait. The negative correlation between the CBH and the BWD could impair the simultaneous selection for both traits, depending on the wood basic density range used by the industry.

Post hoc blocking to improve heritability and precision of best linear unbiased genetic predictions

Single-site clonal trials were simulated with a total of 256 clones "planted" in single-tree plots with three different environmental patterns: only patches (PATCH), only gradients (GRAD), and both components (ALL). Several simulated experimental designs were analyzed (a randomized complete block design; incomplete block designs with 4, 8, 16, and 32 incomplete blocks; and a row-column design) and compared with post hoc blocking of the same designs over a randomized complete block. Additionally, two more incomplete block designs (64 and 128 blocks) were superimposed after the fact to examine extremely small blocks. To select the best fit, the performance of the log-likelihood and mean standard error of the difference (SED) were studied and compared with mean individual broad-sense heritability. Improvement in statistical efficiency (or precision) were obtained with little effort using post hoc blocking. The results from post hoc blocking were promising with negligible differences compared with predesigned local control. The post hoc best designs were row-column (for ALL and PATCH) and incomplete block with eight blocks (for GRAD). Also, mean correlation between the true and predicted values (CORR) showed a reduction in efficiency for extremely small blocks, but no reduction in the genetic variance was noted as the size of the block decreased. Both of the criteria for model selection (log-likelihood and SED) showed similar trend to mean CORR, and their use is recommended.

Mapping QTLs for Witches' Broom (Crinipellis Perniciosa) Resistance in Cacao (Theobroma Cacao L.)

Molecular markers (RAPD, AFLP and microsatellites) were used to generate a linkage map and to identify QTLs associated to witches' broom (Crinipellis perniciosa) resistance in cacao (Theobroma cacao), using 82 individuals of an F2 population derived from the clones ICS-1 (susceptible) and Scavina-6 (resistant). Fifteen evaluations of the number of brooms have been carried out in six years (1997–2002). In order to increase the precision and accuracy in the measures of resistance, each F2 plant was cloned in three replications in a randomized block design with single-tree plots and evaluated over 2 years. Three hundred and forty-two markers were obtained, being 33 microsatellites, 77 AFLPs and 232 RAPDs. The distribution of the number of brooms in the F2 population was skewed to resistance, suggesting the involvement of major genes controlling resistance and the repeatability estimated for resistance was 44%. A strong putative QTL was detected as being related to witches' broom resistance. Associated to this QTL, the microsatellite mTcCIR35 explained 35.5% of the phenotypic variation in resistance. This marker is being used for marker-assisted selection in Scavina-6 progenies, including those selected in private plantations, as an auxiliary tool to the phenotypic selection.

Nitrogen Accumulation and Use by a Young Loblolly Pine Plantation in Southeast Oklahoma: Effects of Fertilizer Formulation and Date of Application

Abstract Practices that enhance crop tree nitrogen (N) accumulation and use improve the efficiency of forest fertilization operations. This study was established to explore the N accumulation and use by a young loblolly pine plantation in response to (1) season of fertilizer application, (2) herbaceous vegetation suppression, and (3) fertilizer formulation. Water-soluble and slow-release urea formulations were applied to single-tree plots in January/February, April, June, August, and October of 2001 and 2002. Herbaceous vegetation was suppressed where appropriate with glyphosate. Foliage N accumulation was measured 1 and 2 months after fertilization; N use efficiency was measured 1 year after fertilization. Between 0.3 and 8.0% of applied N was recovered by the foliage within 1 month of application and 7–26% of applied N was used for stem growth within 1 year of application. In both years of this study, summer and fall applications produced the highest N accumulation and use. Suppressing herbaceous vegetation enhanced N accumulation and use when the plantation was 3 years of age (with an average tree height of 6 ft in January 2001). N accumulation and use of slow-release urea was similar to or lower than that of water soluble urea in both years of the study.

Comparison of Experimental Designs for Clonal Forestry Using Simulated Data

Abstract Various alternatives for the design of clonal field trials in forestry were studied using simulated data to identify “optimal𠇍 or “near-optimal𠇍 scenarios for the estimation of genetic parameters. The simulated field site consisted of a rectangular grid on which 256 clones with 8 ramets each were installed. Estimates of genetic parameters were compared for (1) single-tree and four-tree row plots; (2) several experimental designs (completely randomized, randomized complete block, incomplete blocks of various sizes, and row–column); (3) no mortality versus 257% mortality; and (4) different patterns of environmental variability (only patches, only gradients, and both patches and gradients). Use of single-tree plots, on average, increased the correlations between true and predicted clonal values by 57% over four-tree row plots and increased genetic gain from selection. Starting with a parametric broad-sense heritability (H B 2) of 0.25 for a completely randomized design, the experimental designs resulting in the highest H B 2 were row–column designs for single-tree plots and incomplete blocks with 32 blocks per replication when four-tree row plots were used. These designs increased average heritability 107% and 147% over a randomized complete block design, respectively. The only effect of 257% mortality was an increase in the variability of some variance component estimates.

Heritability and Correlations for Biomass Production and Allocation in White Spruce Seedlings

AbstractTree growth is a multidimensional trait and families vary for components of growth such as height, diameter, foliage and roots. Therefore, variation in tree growth is better studied by analysing biomass production and allocation than simple traits. In addition, biomass is better linked to products such as pulp and wood energy than simple traits. We analysed biomass of 3-year old open-pollinated greenhouse seedlings of white spruce to determine (1) heritability for biomass production and allocation to shoot and root components, (2) correlations between biomass traits, and biomass traits with primary traits, and (3) correlation between biomass production in the greenhouse and height growth for the same families in the field. The study had a randomised complete block design with single-tree plots, 30 blocks and 58 open-pollinated families. Individual-tree heritability (hi2) and family mean heritability (hf2) ranged from 0.200 to 0.333 and 0.374 to 0.516 for green weight, respectively. Likewise, hi2and hi2ranged from 0.186 to 0.359 and 0.352 to 0.536 for dry weight, respectively. Genetic correlation (ra) between green and dry weight ranged from 0.943 to 1.015, while rabetween shoot and root dry weight ranged from 0.947 to 0.955. In contrast, rabetween biomass traits and field height ranged from -0.403 to -0.124. Thus, we conclude (1) variation in biomass production and allocation exhibited low genetic basis, (2) testing and selection for green or dry weight should lead to similar genotypes, (3) biomass allocation may not be easily altered by selection and breeding, and (4) indirect early selection based on seedling biomass

CHESTNUT CULTIVAR EVALUATIONS IN TENNESSEE: ORCHARD ESTABLISHMENT AND EARLY GERMPLASM CHARACTERIZATION

More than 50 named cultivars of Castanea crenata (Japanese Chestnut), C. dentata (American Chestnut), C. henryi (Henry’s Chinkapin), C. mollissima (Chinese Chestnut), C. pumila (Allegheny Chinkapin), C. sativa (European Chestnut), and cultivars of Castanea interspecific hybrids are under evaluation. We started planting in April of 2003. We purchased commercially available, grafted nursery stock of as many cultivars as we could locate. We grafted plants of those cultivars we could not buy. Twenty of the cultivars were planted in a randomized complete block design with twenty trees of each cultivar planted in four five-tree plots. The remaining cultivars and species accessions were planted in single-tree plots, completely randomized, with one or more trees per cultivar, in guard rows around the main blocks. In the first two years of the trial, cultivar differences have been observed for vigor, survival, precocity of bloom, onset of anthesis, full anthesis, ripening date and harvest date, tree form and habit, insect attack and incidence of fungal diseases.