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1.
Ten-year height data from three open-pollinated lodgepole pine progeny test trials were analysed in order to select individuals
for seed orchard establishment in the low and high elevation seed-planning units (TOLO and TOHI) of the new Thompson Okanagan
seed planning-zone in interior British Columbia, Canada. The total test population had about 35,000 individuals from 362 families
of 9 provenances and was divided into two portions, each serving as the base population for its appropriate seed-planning
unit. For each population, various genetic parameters were estimated and individual breeding values were predicted. Combined-site
estimates of individual, family, and within-family heritability ranged from 0.23 to 0.38, 0.77 to 0.84, and 0.17 to 0.29,
respectively. Estimated coefficients of type-b genetic correlation were greater than 0.81, indicating little G × E interaction
in this region. Provenance effects were large. Larch Hills and Inonoaklin River were the two superior provenances with an
expected gain of 13% and 10% in stem volume at rotation age of 60 years in TOLO. Individual breeding values was not uniformly
distributed among provenances and the top 100 individuals originated from 20 families in TOLO and 32 families in TOHI. Co-ancestry
among these individuals should not be a serious concern in seed orchard establishment as the predicted genetic loss due to
excessive inbreeding is only 1.06% in TOLO and 0.6% in TOHI. The status numbers of the two prospective seed orchards are 32
and 44, respectively, and both are well above the required minimum of 10 in British Columbia. Using unrelated clones for seed
orchard establishment may result in reduced optimum genetic gain and thus is not a favourable option. 相似文献
2.
The first generation genetic gains in four second-generation seedling seed orchards of Eucalyptus pellita established at two locations in Indonesia (Kalimantan and Sumatra) were examined by analyzing data on the height, diameter
and stem form of the trees during years 1 to 3. The seed orchards each consisted of 60 open-pollinated families: 48–49 families
from first-generation plus trees (improved population) and 11–12 families from natural forest (unimproved population). The
realized gains for height and diameter were ca. 16 and 19%, respectively. These gains were highly significant and consistent,
irrespective of age and location. However, the gains in stem form were much lower (4%) in Kalimantan than in Sumatra (21%)
and only significant in the latter, possibly because of the more intensive silvicultural management regimes at the Sumatran
sites. The results confirmed that the first-generation tree improvement program for E. pellita has been effective in Indonesia, and that it should provide improved seeds for operational plantation, thus raising their
productivity. 相似文献
3.
From four Korean pine (Pinus koraiensis) orchards, 60 clones were selected and analyzed for the fatty acid and amino acid components of the seeds to reveal the variations and correlations of the seed characteristics among the clonal source orchards and clones. The nutritional components of the seeds of the P. koraiensis trees exhibited rich genetic variation; the variation coefficient of the fatty acids was 2.24–66.83 %, while the variation coefficient of the amino acids was 14.70–38.88 %. Relatively high genetic-improvement potential exists for the nutritional components of the seeds. The phenotypic differentiation of the fatty acid and amino acid components reveals that variation within the population (85.18 %) was the primary source for the variation of the fatty acid components; variation among the orchards (63.08 %) was the primary source of the variation of the amino acid components. Data drawn from various clonal source orchards all showed that the seed characteristics were highly controlled by heritability (h2 > 80 %), and the seed characteristics of the P. koraiensis trees exhibited a similar genetic gain trend. The principal components were analyzed to obtain the comprehensive principal component value for each clonal seed orchard. Twelve clones were selected based on a clonal selection rate of 20 %. Correlation and multiple stepwise-regression analyses were conducted, considering different location conditions, to reveal the stable correlations between the seed characteristics to facilitate improvements of the seed yield of P. koraiensis trees and the clonal selection. Species of real characteristics in P. koraiensis were controlled by higher heritability. Genetic gain was obtained by selecting of superior clones. 相似文献
4.
David Gwaze 《New Forests》2009,37(1):9-16
Genetic and phenotypic correlations for height were estimated for shortleaf pine (Pinus echinata Mill.) in Missouri from a single progeny test comprising 44 half-sibling families assessed at 3, 5, 7, 10, 17 and 25 years
of age. The age-age genetic correlations for height ranged from 0.68 to 0.99, and phenotypic correlations from 0.28 to 0.84.
Age-age phenotypic correlations for height had a strong linear relationship with logarithm of age ratio (R
2 = 0.89) but age-age genetic correlations had a weak linear relationship with logarithm of age ratio (R
2 = 0.27). Early selection efficiency for height was examined using the ratio of gain per year between indirect early selection
and direct selection at age 25. When flowering age was assumed to be 10 years, optimum selection age was predicted to be 10
using either the genetic or the phenotypic linear model. When flowering age was assumed to be 3 years, optimum selection age
was predicted to be 3 and 8 years based on the genetic and phenotypic linear models, respectively. The phenotypic linear model
underestimated genetic gain at all ages, particularly at young ages. 相似文献
5.
Optimum ages for early combined-trait selection were derived for a breeding objective of reducing the total cost of unbleached eucalypt kraft pulp, assuming typical heritabilities and age-age genetic correlations for basic density and growth. The optimum biological selection age, the selection age where average annual gain is maximised, was four years for an assumed rotation age of 15 years. The optimum economic selection age, the selection age where the present value of all future gains is maximised, was three years. These conclusions were relatively robust to changes in assumptions used in analysis. 相似文献
6.
《Scandinavian Journal of Forest Research》2012,27(2):88-98
Abstract The effect of various biological, genetic, economic and management factors relevant to advanced generation seed orchard establishment was investigated using numerical estimates for Scots pine (Pinus sylvestris L.) in Sweden. Factors considered were planting density, rate of genetic advance in the breeding population, timing of first seed collection, seed value, seed production cost (stratified to establishment, annual management, cone harvest and seed extraction), orchard rotation age and contamination level. The developed model demonstrated its utility in studying and evaluating various economic and biological options associated with advanced generation seed orchard establishment/turnover. Sensitivity analyses demonstrated the robustness of the developed model through various arbitrarily changes in genetic gain advances, establishment, management and seed production, particularly those associated with cone harvests from upper crown and costs. The Swedish Scots pine case study produced results supporting faster turnover of seed orchard generations (30 vs 40 years) with shorter orchard lifespan (early start of seed cone after 8 years vs 15 years) delivering higher gain through minimizing the genetic gain differential between the breeding and production populations and allowing the capture of this gain for inclusion in the seed orchards. Orchard planting densities of 400 and 600 grafts per hectare produced similar results with marginal differences, and the latter was recommended for future orchard establishment. 相似文献
7.
Realized genetic gains brought by the first-generation tree improvement of Acacia mangium were evaluated by analyzing the 1-year growth performance of growth (height, dbh) and form (stem straightness, multi-stem) traits using data collected from three second-generation orchards: groups B, C, and D. Each orchard was composed of improved families derived from open-pollinated seed of plus trees selected from the first-generation seed orchards and newly added unimproved families collected from the same geographic region. The number of improved families and that of the unimproved in each orchard were 31 and 23 for group B, 28 and 39 for group C, and 24 and 30 for group D. Gains were calculated as percentage increase of improved families over unimproved ones. Improved families performed better than unimproved ones in 11 out of 12 comparison cases: four traits each in the three orchards. Averages of the realized genetic gain across the three seedling seed orchards were 3.1%, 5.2%, 4.3%, and 0.5% for height, dbh, stem straightness, and multi-stem, respectively. Except for multi-stem, the performances of improved families were significantly better than those of unimproved families in all the three orchards for dbh and in two out of three orchards for height and stem straightness. 相似文献
9.
Genetic variation in the height growth curves was investigated by analyzing data from three clonal trials of sugi (Crytomeria japonica D. Don) in Kyushu. Average height of twelve clones measured at each of five years until 30 years of age were fitted to the
Chapman-Richards function with two parameters model. Clonal variation in the two parameters (an upper asymptote and a rate
of growth parameter) was statistically significant across the tests, indicating that height growth pattern is under genetic
control. The type of growth curve was clearly classified with the two parameters and agreed with the empirical classifications
of the growth habit of local varieties. The rate of growth parameter was correlated with total height up to 20 years of age,
while the upper asymptote was correlated only with the last ten years’ increment from 21 to 30 years where the clonal repeatability
was decreasing. This indicates that a clonal selection for long rotation management system would not be reliable unless the
height is measured accurately with more advanced devices or it is adjusted by the current increment of diameter. 相似文献
10.
Trend of within-plot selection practiced in two seedling seed orchards ofAcacia mangium in Indonesia
A trend of within-plot selection was examined by applying a retrospective selection index to the results of the selection
in two seedling seed orchards ofA. mangium at South Kalimantan in Indonesia. The orchards were established in randomized complete block design with ten replications
of four tree row plots. Within-plot selections were conducted twice with around 50% of selection intensity in those orchards:
at 22 months and at 51 months after planting, then the results were analyzed with the data on volume, stem form and bole length
measured before each selection. Bole length was found to be the highest priority trait throughout the two stages of selection
in both orchards. Growth expressed by volume was also an important criterion at the first within-plot selection, while the
priority was not obvious at the second selection. Expected gains by within-plot selection were generally small, although predicted
gains were positive on all of the three traits at each stage of selection.
The seedling seed orchards analyzed in this study were established under a technical cooperation project between JICA (Japan
International Cooperation Agency) and Ministry of Forestry in Indonesia in collaboration with Inhutani 3. 相似文献
11.
P. K. Pande A. Kumar S. Ravichandran S. Naithani V. Kothiyal P. B. K. Kishore A. Raturi P. Gautam S. Dobhal S. Sharma 《林业研究》2013,24(3):485-493
We selected 28 populations of Leucaena leucocephala from different geographical locations in the states of Andhra Pradesh, Tamil Nadu and Orissa of India on the basis of height and girth at breast height (GBH). We evaluated fiber length, optical density, wall thickness, vessel element length, vessel element diameter, specific gravity and lignin of these populations of L. leucocephala in different sites. Populations had significant variations for all growth, wood and paper parameters. Girth at breast height (GBH) and specific gravity were the most important parameters for heritability and genetic gain, respectively. The minimum heritability was reported for vessel element length and genetic gain for fiber length. The populations were grouped into six clusters, cluster II had maximum number of populations (14) and clusters IV and VI had one population each. GBH contributed maximum of 34.39 % towards total divergence followed by specific gravity (14.02%). An economic technique to produce quality seed by establishing seed orchards with genetically divergent parents was suggested. The hybridization among the populations selected from diverse clusters could produce greater heterosis needed for higher growth and suitable wood and paper manufacturing parameters. 相似文献
12.
Takaaki Fujimoto Kazuhito Kita Kazuko Uchiyama Makoto Kuromaru Hisashi Akutsu Kazuyuki Oda 《Journal of Forest Research》2006,11(3):157-163
Age trends in variance components and heritability of overall wood density, earlywood and latewood density, and latewood proportion
were investigated in 29-year-old trees of 19 full-sib families of hybrid larch (Larix gmelinii var. japonica × Larix kaempferi) F1. The age–age correlation and optimum selection age for these traits were also estimated and genetic and phenotypic correlations
between wood density and radial growth rate were calculated for each growth ring. Intraring wood density data were obtained
using X-ray densitometry. The coefficient of additive genetic variance was stable over all ages, whereas the coefficient of
environmental variances gradually decreased with increasing age, resulting in increases in heritability estimates with age
for overall density. The latewood proportion had the highest heritability estimates at all ages, ranging from 0.44 to 0.66.
Overall density and its various components at 28 years of age showed strong genetic correlations with their respective traits
at all younger ages. Optimum selection ages for the wood density traits ranged from 8 to 14 years, at which point maximum
gain efficiencies per year were obtained. There were negative correlations between wood density and radial growth rate at
early ages, although these relationships tended to be weaker with increasing age. These results suggest that selection at
a young age is effective for wood density, but particular care must be taken in selecting trees with an improved radial growth
rate because rapid growth will result in a low-density wood product, especially in the early growth period. 相似文献
13.
Seeds of 23 relic Metasequoia glyptostroboides trees were randomly collected from their original, natural populations found in Lichuan City, Hubei Province, China. The seed characteristics and growth of their three-year-old progenies were investigated. Results show that the average intra-family coefficient of variation (CV) in height growth of the 23 three-year-old families was 14.53%, slightly higher than that of the inter-family CV (14.02%). Correspondingly, these two parameters for root-collar diameter growth were 15.44% and 13.15%. The 23 relic mother trees were significantly differed in their general combining abilities (GCA) and relative effect values of GCA (RGCA) of height growth and root-collar diameter growth over the three years. Both height and root-collar diameter growth had high family heritability in this seedling stage. After eliminating two inferior families, i.e., 15 and 46, 2.21% of genetic gain in height growth was obtained and 1.50% in root-collar diameter growth. It was also significantly different in crown size and number of branches among the 23 three-year-old seedling families. From a cluster analysis we concluded that eight families, i.e., 23, 28, 29, 30, 31, 33, 35 and 44 displayed superior GCA and RGCA in both height and root-collar diameter growth. Therefore, these relic mother trees displayed their potential as parents in seed orchards. With the exception of family 23, the other seven superior families were all collected at Guihua Village, Zhonglu Town, Lichuan City, which has been identified as an optimum district of M. glyptostroboides for seed collection. 相似文献
14.
Unequal deployment of clones to seed orchards by considering genetic gain, relatedness and gene diversity 总被引：2，自引：0，他引：2
Related clones in seed orchards lead to inbreeding depressionand reduced genetic value of the seeds. This study aims to developthe methodology for deployment of related clones to seed orchardswhen the breeding value and the pedigree are available for eachcandidate. The following goals were considered: high geneticgain, high genetic gain adjusted for predicted inbreeding depression(net gain), high gene diversity, and high effective clone number.The selection strategies included truncation selection withor without relatedness restrictions, maximizing genetic gain(linear deployment) with or without restrictions on relatednessand maximizing net gain. The selection strategies were appliedto Norway spruce seed orchard candidates evaluated in clonaltests. The material comprised full-sib and half-sib relationships.Comparisons were made both at the same gene diversity and atthe effective clone number. Maximizing net gain by unequal rametnumber deployment resulted in considerable higher net gain anda considerable reduction of related ramets in many comparisons.Linear deployment restricted against related clones comparedat the same status number resulted in almost as high net gain.Reduction in gene diversity may be a more important reason toavoid relatives in seed orchards than the subsequent inbreedingfor achieving a high net gain. 相似文献
15.
C.-Y. Xie 《New Forests》2008,36(3):273-284
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. 相似文献
16.
The optimum lifetime of Picea abies seed orchards in Sweden was calculated using a model which considers changes in seed yield over time, annual progress of genetic
gain, establishment, management and seed costs, and both the monetary and genetic value of the seeds produced. The longer
the seed orchard is active, the more genetically outdated the produced seeds will become, and thus their value will decline
with time. A main scenario was constructed using the best available estimates for Swedish Norway spruce and was compared to
various alternatives reflecting likely variations. The optimal lifetimes in all of these scenarios was in the order of 40 years.
Sensitivity analyses showed that use of orchards for slightly more or less than their optimal lifetimes does not lead to large
losses. A more effective tree breeding program could slightly reduce the optimal lifetimes. The optimal lifetime depends strongly
on the relationship between monetary value and genetic gain. Thus, in cases where genetic progress is sufficiently rapid,
the optimal lifetime may be less than 30 years. 相似文献
17.
Burcu Çengel Yasemin Tayanç Gaye Kandemir Ercan Velioglu Murat Alan Zeki Kaya 《New Forests》2012,43(3):303-317
To test how efficiently plantations and seed orchards captured genetic diversity from natural Anatolian black pine (Pinus nigra Arnold subspecies pallasiana Holmboe) seed stands, seed sources were chosen from 3 different categories (seed stands (SS), seed orchards (SO) and plantations
(P)) comprising 4 different breeding zones of the species in Turkey. Twenty-five trees (mother trees) were selected from each
SS, SO and P seed sources and were screened with 11 Random Amplified Polymorphic DNA (RAPD) markers. Estimated genetic diversity
parameters were found to be generally high in all Anatolian black pine seed sources and the majority of genetic diversity
is contained within seed sources (94%). No significant difference in genetic diversity parameters (numbers of effective alleles,
% of polymorphic loci and heterozygosity) among seed source categories was found, except for a slight increase in observed
heterozygosities in seed orchards. For all seed source categories, observed heterozygosity values were higher (Ho = 0.49 for SS, 0.55 for SO and 0.49 for P) than expected ones (He = 0.40 for SS, 0.39 for SO and 0.38 for P) indicating the excess of heterozygotes. In general, genetic diversity in seed
stands has been transferred successfully into seed orchards and plantations. However, the use of seeds from seed orchards
can increase the amount of genetic diversity in plantations further. The study also demonstrated that number of plus-tree
clones (25–38) used in the establishment of seed orchards was adequate to capture the high level of diversity from natural
stands. 相似文献
18.
Daniel J. Chmura Roman Rożkowski Władysław Chałupka 《European Journal of Forest Research》2012,131(4):1229-1243
Tree improvement in Poland has been most advanced for Scots pine, but existing seed orchards have not been progeny-tested yet. We examined variation in growth traits—tree height at ages 4 and 8 years, and diameter at age 13 years—in the common garden experiment testing open-pollinated progenies of 31 seed orchards and 5 commercial seed stands (referred to as populations) at 5 locations. We also examined bud burst phenology at two to five sites at three growing seasons. At one experimental site during the 5th growing season, we measured shoot growth rhythm on all populations. Similar measurements of shoot growth were done on a subset of populations during the 6th growing season together with the analysis of needle growth and foliar chemistry. We found significant variation among populations in growth traits, but also significant population × site (G × E) interactions. We used the regression approach and ecovalence analysis to examine populations’ performance stability. Most populations had average responsiveness to environment, and a set of least-responsive poor-growing populations contributed the most to the G × E interaction. Variation in bud burst phenology was associated with geographical distribution of tested progenies. The early bud-bursting populations originated from the north-eastern to north-central Poland, and a group of late bud-bursting populations originated mainly from the south-eastern region. Correlations between bud burst and growth traits were weak to medium and varied by site, but early bud-bursting populations tended to show stronger growth on height and diameter. We found significant differences among populations in final leader length, shoot elongation time and relative growth rate (RGR). However, RGR and shoot elongation time explained less than 30% of variation in leader length and were weakly correlated with tree height. Populations varied in needle length, specific leaf area and foliar nitrogen concentration, but time trends in these traits did not vary among populations or predefined groups of populations. Therefore, the analysis of growth rhythm or needle traits did not help resolve variation in tree growth to support selection decisions. Contrary to our expectation, progeny of seed orchards did not perform significantly better than that of commercial seed stands. This finding, however, should not be extrapolated beyond our set of populations. Nonetheless, the local seed sources were not always the best. From a selection standpoint, our results help culling the worst populations rather than selecting the best ones. Therefore, testing individual family progeny and genetic roguing of existing seed orchards is highly recommended. 相似文献
19.
Advanced-generation wind-pollinated seed orchard design 总被引：2，自引：0，他引：2
Design criteria for advanced-generation seed orchards are discussed with particular emphasis on the comparison between systematic and randomized designs. A simulation approach was used to compare expected genetic gain from a variety of systematic designs with varying numbers of clones and effective population sizes for intermediate (N=201) and large (N=2001) breeding programs. The types of designs examined included orchards containing 1) only parental or backward selections, 2) offspring or forward selections, and 3) a combination of parental and offspring selections. Assuming random mating, parental orchards always offer more genetic gain than offspring orchards; this difference increases as selection intensity increases. Including the best clones in higher frequencies can yield approximately a 1% marginal increase in genetic gain compared to equal representation for all clones. 相似文献
20.
《Scandinavian Journal of Forest Research》2012,27(3):185-192
Abstract An overall objective of the Swedish Scots pine (Pinus sylvestris L.) tree breeding programme is to increase volume production. Selection is based on height at young age as an indicator of future volume production. This study examined the relationship between height at young age and volume production in block-plots at older ages, and the sustainability of increased growth in volume per unit area using parent breeding values. The study included five trials with controlled pollinated progenies from 71 phenotypically selected plus-trees. Height and diameter were measured in the trials at ages ranging from 7 to 36 years. The genetic correlation between height at 9 years and volume growth per unit area at 30 years of age was 0.8. The additive genetic coefficient of variation for growth per area unit was 17% at the age of 30 years, i.e. first thinning. Based on the estimated parameters, selection of the best 25% genetic entries according to their height at age 9 years resulted in 13% volume gain at age of 30 years, while selection of the 10% best resulted in 18% volume gain. The plus-tree progenies had 12% higher volume growth per unit area than the unimproved commercial check lots, and this difference needs to be added to obtain the total gains. This means that selection of the 25% best parents gave a gain of 25% in volume per hectare compared with unimproved check lots. 相似文献