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1.
R. Wu H. D. Bradshaw Jr. R. F. Stettler 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(7):1110-1119
Nursery growth and dry weight were analyzed for F2 genotypes derived from Populus trichocarpa×P. deltoides that have been field tested with clonal replicates in three different environments. The correlations between nursery and
plantation performance differed among the environments, with higher values at Boardman and Clatskanie (both planted with rooted
cuttings) than Puyallup (planted with unrooted cuttings). At Puyallup, nursery height was more strongly associated with plantation
growth than were nursery diameter and dry weight. Yet, this finding was not supported by QTL mapping. A single overdominant
QTL on linkage group G affected the stem height of both seedlings and resprouts in the nursery but showed nonsignificant LOD
scores for plantation height from ages 1 to 5 at Puyallup. A total of four QTLs were identified for nursery diameter, one
of which on linkage group O also controlled plantation basal area at all ages. Two important nursery QTLs on linkage groups
B and G were used to estimate the relative efficiency of marker-assisted selection for plantation productivity. Despite the
fact that they were not detected in the plantation stage, these two QTLs could significantly increase the proportion of the
phenotypic variance explained by plantation QTLs.
Received: 5 February 1998 / Accepted: 1 April 1998 相似文献
2.
利用6个单拷贝核基因标记,对中国山杨(Populus davidiana Dode)14个自然居群的遗传多样性和遗传分化水平进行了研究。结果表明,中国山杨表现出较高的遗传多样性水平,各居群间基因流(Nm)为0.66;居群内的变异占总变异的百分比(71.82%)大于居群间(28.18%)。Mantel test检验结果显示居群遗传距离和地理距离间没有相关性。失配分布检测显示中国山杨历史上曾经历过种群的扩张。复杂的种群历史动态、高度异交和较高的碱基突变速率是中国山杨遗传多样性水平较高的原因;而较强的花粉和种子扩散能力及中国山杨的连续分布可能是其居群间遗传分化较小的原因。 相似文献
3.
Above- and below-ground characteristics associated with wind toppling in a young Populus plantation 总被引:2,自引:0,他引:2
Damage from a dormant-season windstorm in a 3-year-old Populus research trial differed among four clones and three spacings and between monoclonal and polyclonal plots. Clonal differences
in susceptibility to toppling (or leaning) were associated with both above- and below-ground characteristics. Susceptible
clones had less taper in the lower stem and more weight in branches on the upper stem. The most susceptible clone also had
the most above-ground biomass per unit of cross-sectional root area. The other susceptible clone had the least root system
development in the windward quadrants. Wind toppling was least at the closest spacing. Apparently, mutual support was more
important than individual tree characteristics from which the most damage would be expected at the closest spacing. Differences
between paired trees of the same clone and spacing which did or did not topple were primarily associated with distribution
of root systems by compass quadrant or depth. At the closest spacing where crown sway would have been minimized, trees which
did not topple had greater cross-sectional root area in the windward direction than trees which did topple. At the widest
spacing where crown sway would have been greatest, windfirm trees had greater cross-sectional root area than non-windfirm
trees in both the windward and leeward directions. Toppling was reduced in polyclonal plots; this reduction may have been
the result of more rapid stand differentiation in the polyclonal plots or reduction in the “domino effect” by inclusion of
more windfirm clones in the mixture.
Received: 23 October 1995 / Accepted: 22 February 1996 相似文献
4.
C. E. Durel F. Laurens A. Fouillet Y. Lespinasse 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(8):1077-1085
Genetic parameters (narrow-sense heritabilities and genetic correlations) were estimated for major agronomical traits in
apple from large unbalanced data sets, with the help of wide-pedigree information. The software REML VCE (Groeneveld 1996)
took into account the complex pedigree of the French apple-breeding population, thanks to the restricted maximum likelihood
procedure combined with the construction of the entire relationship matrix between hybrids planted in the field and their
ancestors. Narrow-sense heritability estimates ranged from 0.34 to 0.68 for traits exhibiting a normal distribution. Heritability
values around 0.35–0.40 were obtained for fruit characteristics (size, texture, flavour, juice content, attractiveness, russeting).
Higher values of heritability were obtained for vigour, assessed by the circumference of the trunk (0.51), and powdery mildew
resistance (0.68). Additive genetic correlations between traits were also estimated, showing a very high relationship between
fruit-quality traits. Vigour and powdery mildew resistance were slightly correlated with the other traits. Utilization of
the ‘individual genetic model’ for the estimation of genetic parameters and breeding values in apple is discussed.
Received: 14 June 1997 / Accepted: 4 December 1997 相似文献
5.
Genetic transformation of Populus trichocarpa genotype Nisqually-1: a functional genomic tool for woody plants 总被引:2,自引:0,他引:2
We report here the Agrobacterium-mediated genetic transformation of Nisqually-1, a Populus trichocarpa genotype whose genome was recently sequenced. Several systems were established. Internodal stem segments from vigorously growing greenhouse plants are the explants most amenable to transformation. For the most efficient system, approximately 40% of the stem segments infected with pBI121-containing Agrobacterium tumefaciens C58 produced transgenic calli, as confirmed by beta-glucuronidase (GUS) staining. The regeneration efficiency of independent transgenic plants was approximately 13%, as revealed by genomic Southern analysis. Some transgenic plants were produced in as little as 5 months after co-cultivation. This system may help to facilitate studies of gene functions in tree growth and development at a genome level. 相似文献
6.
Ülo Niinemets 《Trees - Structure and Function》1998,12(7):446-451
Foliar inclination angles, petiole morphology and dry matter partitioning between assimilative and support biomass were studied
in shade-intolerant Populus tremula L. and shade-tolerant Tilia cordata Mill. along a natural light gradient across the canopy. The leaves of sub-canopy species T. cordata were on average exposed to lower irradiances, and they were also more horizontal with greater blade inclination angles (ϕB, defined as the angle between the leaf fall-line and the horizon; ϕB was positive for the leaves inclined upwards, and negative for the leaves inclined downwards) than those in P. tremula. Seasonal average daily integrated quantum flux density (Q
int, mol m–2 day–1) and ϕB were not related in T. cordata, and only a weak negative effect of Q
int on ϕB was detected in P. tremula. Nevertheless, when both species were pooled, there was a strong negative relationship between Q
int and ϕB, implying that the leaves became progressively vertical with increasing height in the canopy. Interspecific differences in
foliage inclination were mainly related to petiole morphology, in particular to petiole length, rather than to contrasting
biomass investment patterns between assimilative and support tissues within the leaf. It was suggested that more horizontal
leaves, resulting from the species-specific structure of petioles, partly explain the superior performance of shade-tolerant
T. cordata in the understory and the sub-canopy.
Received: 13 November 1997 / Accepted: 6 March 1998 相似文献
7.
Jennifer Willms S. B. Rood Walter Willms Melvin Tyree 《Trees - Structure and Function》1998,12(4):215-223
The conservation of riparian (river valley flood plain) forests relies on the provision of instream flows that are sufficient
to sustain tree growth. In the present study, annual branch growth increments were investigated as an indicator of environmental
favorability for riparian cottonwoods. Trees of three species, Populus angustifolia, P. balsamifera, and P. deltoides, and their natural interspecific hybrids, were studied at five sites along the Oldman and South Saskatchewan rivers in Alberta,
Canada. Annual branch growth increments for the interval from 1983 to 1992 were positively correlated with stream flows (r
2 = 0.79 at Lethbridge) and slightly negatively correlated with weather variables that contribute to water demand: evaporation,
temperature, wind, and/or sunshine. The combination of January to May stream flow (water supply) and June evaporation (water
demand) almost entirely accounted for the branch growth variation across years (r
2 = 0.91 at Lethbridge). Tree ring increments were also investigated but were less closely correlated than branch increments
across trees or with stream flow. Branch growth increments thus provide an accurate but short duration (1 or 2 decades) record
of environmental favorability for growth. The close correlation between branch growth and stream flow indicates that water
is the principal limitation to growth of these riparian cottonwoods and that these trees obtained their water from a source
linked to the stream, the riparian water table. Analyses of branch increments should provide a management tool for (i) determining
instream flow needs for riparian cottonwoods and (ii) analyzing impacts of stream flow alterations due to river damming or
water diversion.
Received: 8 May 1997 / Accepted: 23 September 1997 相似文献
8.
Victor L. Barradas Hamlyn G. Jones Jerry A. Clark 《International journal of biometeorology》1998,42(1):34-43
Photosynthetic photon flux density (PPFD) fluctuations were quantified in crops of beans (Phaseolus vulgaris L.) in the field as the canopy developed between July and October. Two different methods were used to select sunflecks and
shadeflecks. Four ranges of zenith angles (60–70°, 50–60°, 40–50° and 30–40°) were selected for analysing PPFD fluctuations.
At the base of the canopy, sunflecks contributed 18%, 53%, 10% and 4% during the 1st, 3rd, 5th and 7th week of growth, respectively.
At a height of 20 cm above the soil surface, the respective contributions were 28% and 21% during the 6th and 7th weeks. Sunfleck
lengths of 0–5 s were the most frequent, with the greatest number being found with smaller zenith angles. The proportion of
short duration sunflecks increased as the growth period advanced. The number of long sunflecks decreased with time, with very
few longer than 100 s by the 5th and 7th weeks. The distributions of sunfleck irradiance were similar to normal distributions
and irradiance ranged in μmol m−2 s−1 from 600–900, 800–1500 and 1000–1600 respectively at zenith angles of 50–60°, 40–50° and 30–40°. A multiple regression showed
that short sunflecks (<100 s) depended on zenith angle, plant height, and leaf and stem area index (L
s
), whereas long sunflecks (>100 s) depended on zenith angle and L
s. Shadefleck distributions were similar to those for sunflecks but there were fewer of the shortest examples and more of the
longest. The best statistical distribution to describe sunflecks and shadeflecks was the gamma distribution, which could provide
the basis for the future development of a good model for sunfleck and shadefleck distributions.
Received: 10 November 1997 / Accepted: 2 April 1998 相似文献
9.
Kaczorowski RL Juenger TE Holtsford TP 《Evolution; international journal of organic evolution》2008,62(7):1738-1750
The heritability and genetic basis of nectar traits have been rarely studied in the field, where plants are exposed to environmental factors that could mask underlying genetic effects. Heritabilities and variance components were estimated for nectar and morphological traits of Nicotiana alata , using a partial diallel design. The main experiment was conducted in a Missouri experimental garden using a randomized block design with three plant density treatments, whereas a smaller experiment was conducted near native Brazil habitat to compare the environmental variance in traits between Missouri and Brazil. Significant heritability was detected for nectar volume and energy content, and for corolla tube length. Phenotypic correlations were significant between all traits investigated, whereas significant genetic correlations were only found between nectar volume and energy and between corolla limb width and mouth diameter. There were no significant family-by-density interactions detected in the Missouri field environment. All traits differed significantly between Missouri and Brazil environments, but significant genetic by environment (G × E) interactions between Missouri and Brazil were detected for only one trait. This study shows that nectar traits can be heritable despite considerable environmental variation. 相似文献
10.
《Animal : an international journal of animal bioscience》2019,13(8):1576-1582
Body weight and body measurements are commonly used to represent growth and measured at several growth stages in beef cattle. Those economically important traits should be genetically improved. To achieve breeding programs, genetic parameters are prerequisite, as they are needed for designing and predicting outcomes of breeding programs, as well as estimating of breeding values. (Co)variance components were estimated for BW and body measurements on Brahman cattle born between 1990 and 2016 from 17 research herds across Thailand. The traits measured were BW, heart girth (GR), hip height (HH) and body length (BL) and were measured at birth, 200 days, 400 days and 600 days of age. The number of records varied between traits from 18 890 for birth BW to 876 for GR at 600 days. Estimation of variance components was performed using restricted maximum likelihood using univariate and multivariate animal models. Pre-weaning traits were influenced by genetic and/or permanent environmental effects of the dam, except for BL. Heritability estimates from birth to 600 days of age ranged from 0.28±0.01 to 0.50±0.06 for BW, 0.27±0.01 to 0.43±0.09 for GR, 0.28±0.01 to 0.58±0.08 for HH and 0.34±0.01 to 0.51±0.08 for BL using univariate analysis. Heritability estimates for the traits studied increased with age. A similar trend was observed for the phenotypic and genetic correlations between subsequent BW and body measurements. A positive correlation was observed between different traits measured at a similar age, ranging from 0.22±0.01 to 0.72±0.01 for the phenotypic correlation and 0.25±0.04 to 0.97±0.11 for the genetic correlation. Also, a positive correlation was observed for similar traits across different age classes ranging from 0.07±0.03 to 0.76±0.02 for the phenotypic correlation and 0.24±0.11 to 0.92±0.05 for the genetic correlation. Therefore, all correlations between body measurements at the same age and across age classes were positive. The results show the potential improvement of growth traits in Brahman cattle, and those traits can be improved simultaneously under the same breeding program. 相似文献
11.
Development and characterization of microsatellite markers in black poplar (Populus nigra L.) 总被引:6,自引:0,他引:6
J. van der Schoot M. Pospíšková B. Vosman M. J. M. Smulders 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(1-2):317-322
Using an enrichment procedure, we have cloned and sequenced microsatellite loci from black poplar (Populus nigra L.) and developed primers for sequence-tagged microsatellite (STMS) analysis. Twelve primer pairs for dinucleotide repeats
produced fragments of sufficient quality which were polymorphic in P. nigra. Some of them also showed amplification in other Populus species (P. deltoides, P. tricocarpa, P. tremula, P. tremuloides, P. candicans, and/or P. lasiocarpa). The best nine and (GT) (GA) microsatellite markers were tested on a set of 23 P. nigra genotypes from all over Europe. The microsatellites were highly polymorphic, with 10–19 different alleles per microsatellite
locus among these 23 genotypes. WPMS08 sometimes amplified three fragments. Using the other eight marker loci, the level of
heterozygosity among the plants was on average 0.71 (range 0.25–1.00). The microsatellite markers developed will be useful
for screening the genetic diversity in natural populations and in gene bank collections.
Received: 21 October 1999 / Accepted: 24 November 1999 相似文献
12.
13.
C. A. Savary Monica L. Grazziutti Bohuslav Melichar Donna Przepiorka Ralph S. Freedman Richard E. Cowart D. M. Cohen E. J. Anaissie Darren G. Woodside Bradley W. McIntyre Duane L. Pierson Neal R. Pellis John H. Rex 《Cancer immunology, immunotherapy : CII》1997,45(5):234-240
We studied the potential of multidimensional flow cytometry to evaluate the frequency and maturation/activation status of
dendritic cells in minimally manipulated peripheral blood mononuclear cell preparations (i.e., only separated on Ficoll-Hypaque)
of normal donors and cancer patients. A rare subset of HLA-DR+ leukocytes (less than 1% mononuclear cells) was detected in blood of normal donors that displayed all the features of dendritic
cells: these cells had high forward-light-scatter characteristics and coexpressed CD4, CD86 and CD54 surface antigens, but
lacked the lineage-associated surface markers of T cells, B cells, monocytes, granulocytes or NK i.e. they were CD3–, CD19–, CD20–, CD14–, CD11b–, CD16–, CD56–). These physical and phenotypic properties were virtually identical to those of immunomagnetically sorted leukocytes characterized
as dendritic-cells on the basis of morphology, phenotype and high stimulatory activity in allogeneic mixed-lymphocyte cultures.
Using this flow-cytometric approach we observed that the frequency of dendritic cell-like cells in peripheral blood mononuclear
cell specimens of cancer patients receiving chemotherapy alone or those recovering from stem cell transplantation was significantly
lower than that of normal individuals (mean ± SE: 0.36 ± 0.05%, 0.14 ± 0.06%, and 0.75 ± 0.04% respectively). Multidimensional
flow-cytometric analysis of dendritic cells might represent an important new tool for assessing immunocompetence, and for
monitoring the effects of therapeutic regimens on the immune system.
Received: 20 June 1997 / Accepted: 14 August 1997 相似文献
14.
Isolation and characterization of microsatellites in trembling aspen (Populus tremuloides) 总被引:13,自引:0,他引:13
S. Dayanandan O. P. Rajora K. S. Bawa 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(6-7):950-956
We have identified, isolated, and characterized microsatellite/simple sequence repeat (SSR) loci in trembling aspen (Populus tremuloides) by screening partial genomic libraries. We have also examined the compatibility and use of the P. tremuloides SSR primers to resolve microsatellites in other Populus species. Fourteen microsatellites were identified from 1600 clones screened. The TC/AG microsatellites were the most abundant.
A total of 29 alleles were detected in 36 P. tremuloides individuals at the four SSR loci (two each of di- and tri-nucleotide repeats) characterized. The number of alleles at the
SSR loci ranged from 5 to 11, with an average of 7.25 alleles per locus, and the observed heterozygosity ranged from 0.19
to 0.82, with a mean of 0.46 per locus. Although the highest polymorphism was observed for a dinucleotide SSR locus, the trinucleotide
SSR loci showed substantial polymorphism. There were 34 unique multilocus genotypes among the 36 P. tremuloides individuals examined, and 89% of the individuals had unique multilocus genotypes. Two pairs of SSR primers were successful
in PCR, amplifying genomic DNA and resolving microsatellites of comparable size from Populus deltoides, P. nigra, P.×canadensis, and P. maximowiczii. The microsatellite DNA markers developed could be used for clonal fingerprinting, certification of controlled crosses, genome
mapping, marker-assisted early selection, genetic diversity assessments, and conservation and sustainable management of poplar
genetic resources.
Received: 14 November 1997 / Accepted: 17 November 1997 相似文献
15.
Camillo Bérénos Philip A. Ellis Jill G. Pilkington Josephine M. Pemberton 《Molecular ecology》2014,23(14):3434-3451
The estimation of quantitative genetic parameters in wild populations is generally limited by the accuracy and completeness of the available pedigree information. Using relatedness at genomewide markers can potentially remove this limitation and lead to less biased and more precise estimates. We estimated heritability, maternal genetic effects and genetic correlations for body size traits in an unmanaged long‐term study population of Soay sheep on St Kilda using three increasingly complete and accurate estimates of relatedness: (i) Pedigree 1, using observation‐derived maternal links and microsatellite‐derived paternal links; (ii) Pedigree 2, using SNP‐derived assignment of both maternity and paternity; and (iii) whole‐genome relatedness at 37 037 autosomal SNPs. In initial analyses, heritability estimates were strikingly similar for all three methods, while standard errors were systematically lower in analyses based on Pedigree 2 and genomic relatedness. Genetic correlations were generally strong, differed little between the three estimates of relatedness and the standard errors declined only very slightly with improved relatedness information. When partitioning maternal effects into separate genetic and environmental components, maternal genetic effects found in juvenile traits increased substantially across the three relatedness estimates. Heritability declined compared to parallel models where only a maternal environment effect was fitted, suggesting that maternal genetic effects are confounded with direct genetic effects and that more accurate estimates of relatedness were better able to separate maternal genetic effects from direct genetic effects. We found that the heritability captured by SNP markers asymptoted at about half the SNPs available, suggesting that denser marker panels are not necessarily required for precise and unbiased heritability estimates. Finally, we present guidelines for the use of genomic relatedness in future quantitative genetics studies in natural populations. 相似文献
16.
Ü. Niinemets 《Trees - Structure and Function》1997,11(3):144-154
Variations in the partitioning of foliar carbon and nitrogen in combination with changes in needle and shoot structure were
studied in trees of Picea abies along a vertical gradient of relative irradiance (RI). RI was the major determinant of needle morphology, causing all needle
linear parameters – width, thickness and length – to increase. Due to the different responsiveness of needle thickness and
width in respect of RI, the ratio of total to projected needle area increased with RI. Furthermore, shoot structure was also
influenced by RI, and the ratio of shoot silhouette area to total needle area, which characterises the packing of needles
and needle area within the shoot, was greater at lower values of irradiance. Needle dry weight per total needle area (LWAt) was also increased by RI. Similarly, irrespective of the measure for surface area, needle nitrogen content per area, as
the product of needle dry weight per area and nitrogen content per needle dry weight (Nm), scaled quasi-linearly with needle weight per area. Thus, the changes in needle and shoot morphology made it possible to
invest more photosynthesising weight per unit light-intercepting surface there, where the pay-back due to elevated irradiances
was the highest. However, Nm behaved in an entirely different manner, decreasing hyperbolically with LWAt. Since non-structural (carbon in non-structural carbohydrates), and structural (total minus non-structural) needle carbon
per dry weight also increased with LWAt, Nm was inversely correlated with both non-structural and structural carbon. Total tree height, increasing significantly LWAt, also influenced needle structure. It appeared that total height did not affect needle thickness or width, but larger trees
had greater needle density (dry weight per volume). Because needle density was positively correlated with needle carbon content
per dry weight, it was assumed that the greater values of needle carbon content can be attributed to increased lignification
and thickening of needle cell walls. Thus, it appeared that the proportion of supporting structures was greater in needles
of larger trees. Inasmuch as an increased fraction of supporting structures dilutes other leaf substances, including also
leaf compounds responsible for CO2-assimilation, enhanced requirement for supporting structures may be responsible for lower rates of carbon assimilation per
foliage dry weight observed in large trees. Increasing water limitation with increasing tree size is discussed as a possible
cause for increased needle supporting costs in large trees.
Received: 2 April 1995 / Accepted: 16 February 1996 相似文献
17.
Influence of stand structure on carbon-13 of vegetation, soils, and canopy air within deciduous and evergreen forests in Utah, United States 总被引:15,自引:0,他引:15
Carbon isotope ratios (δ13C) were studied in evergreen and deciduous forest ecosystems in semi-arid Utah (Pinus contorta, Populus tremuloides, Acer negundo and Acer grandidentatum). Measurements were taken in four to five stands of each forest ecosystem differing in overstory leaf area index (LAI) during
two consecutive growing seasons. The δ13Cleaf (and carbon isotope discrimination) of understory vegetation in the evergreen stands (LAI 1.5–2.2) did not differ among canopies
with increasing LAI, whereas understory in the deciduous stands (LAI 1.5–4.5) exhibited strongly decreasing δ13Cleaf values (increasing carbon isotope discrimination) with increasing LAI. The δ13C values of needles and leaves at the top of the canopy were relatively constant over the entire LAI range, indicating no
change in intrinsic water-use efficiency with overstory LAI. In all canopies, δ13Cleaf decreased with decreasing height above the forest floor, primarily due to physiological changes affecting c
i/c
a (> 60%) and to a minor extent due to δ13C of canopy air (< 40%). This intra-canopy depletion of δ13Cleaf was lowest in the open stand (1‰) and greatest in the denser stands (4.5‰). Although overstory δ13Cleaf did not change with canopy LAI, δ13C of soil organic carbon increased with increasing LAI in Pinus contorta and Populus tremuloides ecosystems. In addition, δ13C of decomposing organic carbon became increasingly enriched over time (by 1.7–2.9‰) for all deciduous and evergreen dry temperate
forests. The δ13Ccanopy of CO2 in canopy air varied temporally and spatially in all forest stands. Vertical canopy gradients of δ13Ccanopy, and [CO2]canopy were larger in the deciduous Populus tremuloides than in the evergreen Pinu contorta stands of similar LAI. In a very wet and cool year, ecosystem discrimination (Δe) was similar for both deciduous Populus tremulodies (18.0 ± 0.7‰) and evergreen Pinus contorta (18.3 ± 0.9‰) stands. Gradients of δ13Ccanopy and [CO2]canopy were larger in denser Acer spp. stands than those in the open stand. However, 13C enrichment above and photosynthetic draw-down of [CO2]canopy below tropospheric baseline values were larger in the open than in the dense stands, due to the presence of a vigorous understory
vegetation. Seasonal patterns of the relationship δ13Ccanopy versus 1/[CO2]canopy were strongly influenced by precipitation and air temperature during the growing season. Estimates of Δe for Acer spp. did not show a significant effect of stand structure, and averaged 16.8 ± 0.5‰ in 1933 and 17.4 ± 0.7‰ in 1994. However,
Δe varied seasonally with small fluctuations for the open stand (2‰), but more pronounced changes for the dense stand (5‰).
Received: 15 April 1996 / Accepted: 19 October 1996 相似文献
18.
H. Huang J. Harding 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(1-2):316-322
A sample of 36 flower traits consisting of six morphological categories in the Davis population of gerbera was restructured
into phenotypic and genetic principal component traits. The first 5 phenotypic principal component traits accounted for 62%
of the total phenotypic variance of the 36 traits and have moderate to high heritablities. The first 5 genetic principal component
traits account for 97% of total genetic variance and all have high heritability. Morphological structure of these component
traits suggest an underlying process identified by the first genetic principal component involving largely trans and disk
floret traits. The results of this study indicate that the quantitative genetic structure of the gerbera flower is controlled
by a few independent components and that principal component analysis is a useful tool to reveal variation in this structure.
These composite traits are heritable and are expected to respond to selection.
Received: 20 September 1997 / Accepted: 19 January 1998 相似文献
19.
Roulin A 《Biological reviews of the Cambridge Philosophical Society》2004,79(4):815-848
The hypothesis that ornaments can honestly signal quality only if their expression is condition-dependent has dominated the study of the evolution and function of colour traits. Much less interest has been devoted to the adaptive function of colour traits for which the expression is not, or is to a low extent, sensitive to body condition and the environment in which individuals live. The aim of the present paper is to review the current theoretical and empirical knowledge of the evolution, maintenance and adaptive function of colour plumage traits for which the expression is mainly under genetic control. The finding that in many bird species the inheritance of colour morphs follows the laws of Mendel indicates that genetic colour polymorphism is frequent. Polymorphism may have evolved or be maintained because each colour morph facilitates the exploitation of alternative ecological niches as suggested by the observation that individuals are not randomly distributed among habitats with respect to coloration. Consistent with the hypothesis that different colour morphs are linked to alternative strategies is the finding that in a majority of species polymorphism is associated with reproductive parameters, and behavioural, life-history and physiological traits. Experimental studies showed that such covariations can have a genetic basis. These observations suggest that colour polymorphism has an adaptive function. Aviary and field experiments demonstrated that colour polymorphism is used as a criterion in mate-choice decisions and dominance interactions confirming the claim that conspecifics assess each other's colour morphs. The factors favouring the evolution and maintenance of genetic variation in coloration are reviewed, but empirical data are virtually lacking to assess their importance. Although current theory predicts that only condition-dependent traits can signal quality, the present review shows that genetically inherited morphs can reveal the same qualities. The study of genetic colour polymorphism will provide important and original insights on the adaptive function of conspicuous traits. 相似文献
20.
J. Oleksyn Mark G. Tjoelker Gabriela Lorenc-Plucińska Agata Konwińska Roma Żytkowiak Piotr Karolewski Peter B. Reich 《Trees - Structure and Function》1997,12(2):82-89
Pinus heldreichii Christ is a long-lived, slow-growing Tertiary relict from the Balkans. In this study we evaluated the physiological characteristics
of eight needle-age classes of P. heldreichii grown at the Arboretum of the Institute of Dendrology in Kórnik, Poland. At the end of the growing season, current-year foliage
had the highest rates of mass-based light-saturated net photosynthesis (Asat) of 33.5 nmol CO2· g–1· s–1. Asat decreased with needle age, but older needle classes retained from approximately 62 to 26% of the current needles’ rate. The
relationship between leaf N and chlorophyll a concentration among all needle-age classes was highly significant (r = 0.96, P = 0.0006). The variation in Asat of 1- to 7-year-old needles was linearly related to needle N concentration (r = 0.98, P = 0.0001). Needle dark respiration rates among these needle age classes ranged from 0.8 to 2.2 nmol · g–1· s–1 and decreased with needle age and nitrogen concentration. Total phenols and glucose concentrations increased linearly with
needle age. A similar pattern was observed in acid buffering capacity and the pH of tissue homogenates. The water content
ranged from 62% for the current needles to 51% for the 6-year-old needles. Greater investment in leaf structural tissue and
increased chemical defense is associated with higher structural cost of older needles and may reduce their photosynthetic
activity. Significant declines in water and nitrogen content with needle age and an increase in content of phenolics is most
likely a defense adaptation of P. heldreichii related to the species’ long-lived leaves.
Received: 8 January 1997 / Accepted: 4 March 1997 相似文献