首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The management of a genetic improvement program is based on the knowledge of the genetic parameters and their relationships to determine the genetic gains. Knowledge of the coefficient of coancestry (θ) is a requirement for efficient progeny testing scheme and for estimating additive variance components for any quantitative trait. When using open-pollinated families, most authors assume that the seedlings are related as half-sibs, but this is not always true. Our aim was to estimate a mean value of the coancestry coefficient of the families present in a maritime pine Pinus pinaster Ait. (maritime or cluster pine) progeny trial originating from seed collected in a clonal seed orchard and to study how deviations from the standard assumption of θ = 0.125 affect heritability estimations. Five highly polymorphic microsatellite markers were scored in 125 offspring from a subsample of five families from the progeny trial. The mean value of the coancestry coefficient of the families present in this progeny trial was 0.130. Differences between the unadjusted and adjusted heritability estimates were more pronounced in wood density (0.609 and 0.586, respectively) than in diameter (0.166 and 0.154, respectively). We conclude that in the trial, the associated error in heritability estimates due to the inclusion of full-sibs, when assuming a standard coefficient of relationship among open-pollinated sibs of 0.250, was low and that this result is robust with respect to the number of families sampled, given unbiased estimates of average relationship among offspring within sib families.  相似文献   

2.
Summary Growth traits, stem form and branch characteristics in three series of well-replicated trials, comprising open-pollinated families of Pinus elliottii Engelmann, were analysed to investigate whether the absolute value of the component of variance for family effect and its relative value (which is equivalent to one-quarter of heritability on individual values) were related, with trial averages of the traits studied taken as productivity indices of the sites tested. The first series, called the foreign selection series, consisted of four trials comprising open-pollinated families from single clones from a Florida seed orchard and from selected trees in Queensland, Australia. Two trials were established in the eastern Transvaal, at Tweefontein and Frankfort State Forests (SF), and two in Zululand, at Dukuduku and KwaMbonambi SF. The second series, called the Zululand selection series, consisted of open-pollinated families from single trees selected in Zululand that were compared in three trials: in the eastern Transvaal at Wilgeboom SF, in Zululand at Dukuduku SF and in the southern Cape at Lottering SF. The third series, called the South African selection series, consisted of open-pollinated families from single trees selected in the different forest areas of South Africa and compared in four trials: two trials in the eastern Transvaal at Tweefontein and Mariti SF and two in the Natal province at Dukuduku and Weza SF. Some positive and linear relationships between absolute sizes of the variance component for family and trial average for all traits studied, except stem form, were discernible for the foreign selections and for the Zululand selections. The South African selections presented a more erratic pattern of variation. However, when the origin of the genetic material was disregarded, the positive trends were undeniable. Curvilinear relationships between relative values and site averages were discernible, when the origin of the genetic material was disregarded. Further research is needed in order to confirm the suggested effect of site on genetic expressivity of open-pollinated families of slash pine grown in South Africa.  相似文献   

3.
Growth and form traits data were obtained from eight provenance trials of radiata pine (Pinus radiata D. Don) planted across the radiata pine plantation estate in southeast Australia. The genetic pool included 466 open-pollinated families collected from A?o Nuevo, Monterey and Cambria provenances on the Californian mainland coast in the USA and from Guadalupe and Cedros islands off the coast of Baja California in Mexico. Early survival of all provenances was around 90%, except for Cedros (<60%). Monterey and A?o Nuevo were the best performers at almost all sites. However, good growth performance of Cambria and good stem straightness of Guadalupe on some sites are important results, because the genetic base of the present Australian plantations evidently originated from only Monterey and A?o Nuevo. The average estimated single-site heritability for diameter at breast height was 0.22 and 0.32 at juvenile and mature ages, respectively. Heritability estimates for stem straightness and branching ranged from 0.23 to 0.55. Genetic correlation estimates between diameter at breast height (DBH) at juvenile and rotation ages were all >0.80. Estimates of between-site genetic and provenance correlations for DBH were often low, indicating high genotype by environment interaction across trials, consistent with previous Australian studies. However, there was minimal G × E among trials on high-altitude high-rainfall sites and among trials on low-altitude, low-rainfall sites.  相似文献   

4.
Two trials on Mexican cypress Cupressus lusitanica Miller in the North Island of New Zealand were assessed for diameter at breast height and at one site, subjective scores for branch size and stem canker (caused by Seiridium spp.) at age 6 from planting. The trials comprised 15 open-pollinated families, represented by both cloned and seedling progeny. Linear mixed model methodology, using a spatial model for the residuals, was applied to estimate genetic parameters. Estimated narrow-sense heritabilities were moderate to high for diameter at breast height (range from 0.46 to 0.62), stem canker (≈0.30) and branch size (range from 0.23 to 0.45) and did not appear to differ significantly between propagule types for all traits. Clonally replicated progeny led to an increase in accuracy of selection for additive genetic merit when compared with seedling testing, with the improvement being greater for traits with lower narrow-sense heritabilities. Estimated additive genetic correlations between cloned and seedling progeny were moderate to high (≥0.65) for diameter and branch size, indicating that selection decisions would not be substantially changed using either propagule type for progeny testing. All estimates of non-additive genetic variation based on the cloned progeny were non-significant. The use of spatial analysis was effective for diameter and branch size, but not for stem canker. No significant genotype by environment interaction was detected for diameter. Implications of the results for breeding and deployment of C. lusitanica are discussed.  相似文献   

5.
The fungal pathogen Quambalaria pitereka can cause significant damage to spotted gum (Corymbia sp.) plantations in Australia. A series of seven progeny trials, involving seed from a range-wide collection from 527 individuals within 25 native populations of Corymbia citriodora sub-species variegata, were assessed for height growth and damage from Quambalaria around 1 year after planting. Infection at this young age has been found to detrimentally impact growth, form, and wood quality for many years. Genetic variance was found to be significant at both the provenance and family level. However, selection of families within provenances should lead to greater levels of genetic gain than what can be realized from selecting among provenances as estimates of additive genetic variance were consistently greater than estimates of variance among populations. Strong relationships between height and Quambalaria shoot blight (QSB) damage assessments in these trials were evidenced by very high genetic correlations between the traits; therefore, selection for any of these traits could be used to identify more productive and QSB-tolerant populations. While both provenances and families were found to interact with the trial environments at a similar level across traits, genetic correlations indicated that rankings for growth were be less stable than rankings for QSB tolerance across environments. Genetic parameter estimates derived from general and generalized linear models were very similar and either analytical method could be used to evaluate fungal damage.  相似文献   

6.
为筛选苗期表现优良的山鸡椒[Litsea cubeba(Lour.)Pers.]种源/家系,对其13个种源55个家系的苗高(h)、地径(bd)性状进行遗传变异分析。结果表明,山鸡椒1年生苗木生长期可分为生长初期、速生期和完全木质化期,苗高、地径生长不同步。山鸡椒不同种源、家系间的苗高、地径生长量均存在极显著差异(P0.01)。利用综合选择指数法建立综合选择式为I=0.007Xh+0.74Xbd,建阳2号、富阳1号、遂昌8号、遂昌13号和岳西1号等5个家系优良度为I级,入选率为9.1%。浙江富阳和福建建阳2个种源的苗高、胸径期望遗传增益值最高;建阳2号、遂昌8号、富阳1号、遂昌13号、岳西1号、建阳3号、岳西6号等7个家系的苗高、胸径期望遗传增益最高。因此,依据生长性状综合选择和遗传增益表现,选择出建阳2号、富阳1号、遂昌8号,遂昌13号,岳西1号5个家系以及浙江富阳和福建建阳2个种源为优良家系/种源。  相似文献   

7.
Most plant species, particularly long-lived plants, harbor a large amount of genetic variation within populations. A central issue in evolutionary ecology is to explore levels of genetic variation and understand the mechanisms that influence them. In this study, our goals were to examine the impact of neutral evolutionary processes on the genetic variance and functional diversity within three populations of a long-lived plant (Quercus suber L.). For this purpose, we genotyped the progeny of 45 open-pollinated mother trees from three populations originating from Spain, Portugal, and Morocco using six microsatellite markers. Seedlings were planted in a common garden trial and were phenotypically characterized by seven leaf functional traits. Molecular analyses revealed weak genetic differences between Iberian and Moroccan populations. Nevertheless, high genetic differentiation was observed among maternal families within populations. Differentiation between particular maternal families from the same population reached values of 29.2 %, which far exceeds the values reported between the most genetically distant populations for this species (11.7 %). Maternal families differed also in phenology, leaf size, and shape traits. In the Moroccan population, there were correlations among matrices of distances for molecular markers, leaf shape traits (e.g., leaf circularity index), and phenology, indicating that maternal families with contrasting phenologies were genetically and functionally distinct. This, together with the moderate heritability for phenology in Moroccan population, suggests that besides selective forces, neutral evolutionary processes have promoted intrapopulation genetic divergence and contribute to maintain high levels of genetic variation within this population. Overall, our results reinforce the importance of intrapopulation studies in long-lived plants under an evolutionary context.  相似文献   

8.
不同种源厚朴苗期性状变异及主成分分析   总被引:2,自引:0,他引:2  
基于厚朴(Magnolia officinalis)作为一种传统中药植物及分布区域广、环境异质化程度明显的现象,采用田间种源实验,对分布在中国7个省的14个种源厚朴苗期的生长性状进行了观测分析。结果表明,不同种源厚朴的苗期生长性状差异显著。种源遗传力分析表明,苗高和单株叶面积两个性状的遗传力较高,分别为0.93、0.79,可认为以苗高和单株叶面积为主的种源多性状综合选择改良潜力巨大。相关性分析表明各性状间遗传相关、表型相关、环境相关均存在一定的相关关系,单株叶面积和地上部生长性状的遗传相关程度高于地下部生长性状,表型显著相关的性状组合数量和程度低于遗传相关。厚朴苗期种源选择的首选因子为各生物量及单数叶面积性状,辅助因子为苗高和地径。通过系统聚类分析,初步选定景宁、武夷山、龙胜、开县、城固、宁强及洋县的种源为优良厚朴种源。  相似文献   

9.
不同种源樟树叶片形态特征及生长差异分析   总被引:1,自引:0,他引:1  
为了解不同种源樟树叶片形态特征和生长差异,该文以30个种源樟树为研究对象,对其叶长、叶宽、叶柄长、周长、叶面积、长宽比、形态因子、株高、地径等指标进行测定和差异性分析.结果表明:(1)30个种源间叶片性状的变异系数为3.88%~16.14%,显示不同种源樟树叶片形态特征存在显著差异;叶长、叶宽、叶柄长、周长、面积、叶厚...  相似文献   

10.
Genetic parameters for growth, stem straightness, pilodyn penetration, relative bark thickness and survival were estimated in a base-population of five open-pollinated provenance/progeny trials of Eucalyptus viminalis. The trials, located in northern, central and southern Buenos Aires Province, Argentina, comprised 148 open-pollinated families from 13 Australian native provenances and eight local Argentinean seedlots. The Australian native provenances come from a limited range of the natural distribution. Overall survival, based on the latest assessment of each trial, was 62.4%. Single-site analyses showed that statistically significant provenances differences (p?<?0.05) for at least one of the studied traits in three out of the five trials analyzed. The local land race performed inconsistently in this study. The average narrow-sense individual-tree heritability estimate $ \left( {{{\hat{h}}^2}} \right) $ was 0.27 for diameter and 0.17 for total height. Values of $ {\hat{h}^2} $ also increased with age. Pilodyn penetration, assessed at only one site, was more heritable $ \left( {{{\hat{h}}^2} = 0.32} \right) $ than the average of growth traits. Estimated individual-tree heritabilities were moderate to low for stem straightness (average of 0.20) and relative bark thickness (0.16). The estimated additive genetic correlations $ \left( {{{{r}}_{{A}}}} \right) $ between diameter and height were consistently high and positive ( $ {{r}_{^A}} $ average of 0.90). High additive genetic correlations were observed between growth variables and pilodyn penetration ( $ {{r}_{^A}} $ average of 0.58). Relative bark thickness showed a negative correlation with diameter $ \left( {{{{r}}_{^A}} = - 0.39} \right) $ and height $ \left( {{{{r}}_{^A}} = - 0.51} \right) $ . The average estimated additive genetic correlation between sites was high for diameter (0.67). The implications of all these parameter estimates for genetic improvement of E. viminalis in Argentina are discussed.  相似文献   

11.
为选育枫香(Liquidambar formosana)优良家系,对其24个种源310个家系的遗传变异进行分析,采用多目标决策法选育用材林优良家系及单株。结果表明,9年生枫香胸径、树高、材积、第一枝下高、冠幅和树干通直度等性状在种源和家系间存在显著差异(P0.01),以云南富宁、广西凭祥和江西湖城3个种源的材积生长表现最佳。各性状的家系遗传力属于中等遗传控制,为0.24~0.44,单株遗传力为0.20~0.50。共选出优良家系26个和单株41株,优良家系的平均胸径、树高、材积、冠幅、树干通直度分别大于总体均值的19.63%、18.56%、52.16%、5.11%和4.03%;遗传增益分别为6.67%、8.24%、20.28%、1.82%和1.75%,优良单株平均材积大于总体均值的150.25%。这为枫香育种策略制定和生产应用等提供理论依据。  相似文献   

12.
米老排种源家系生长性状变异分析及早期选择   总被引:1,自引:0,他引:1  
为分析米老排生长性状在种源和家系间的变异规律,筛选出速生的米老排优良种源和家系。以来自8个米老排地理种源的116个家系为研究对象,对米老排生长性状进行种源间和家系间遗传变异分析和育种值综合评分。结果表明:不同米老排种源间和家系间生长性状的差异均达到极显著水平。生长量最高的GXPX种源的平均树高、胸径和单株材积分别为9.50 m、13.40 cm、0.079 9 m3,是最差种源GXFC的1.28、1.42和2.30倍;生长最快家系是PX01,其平均树高、胸径和单株材积分别为9.86 m、15.31 cm和0.101 6 m3,其株材积是最差家系FC01的4.01倍,是家系群体均值的1.94倍。通过单性状选择对种源进行选择,初步选出2个优良种源,其树高、胸径和单株材积的预期遗传增益分别达到8.87%、11.79%和34.70%;运用育种值综合评分法对家系进行选择,初步选出12个优良家系,其树高、胸径树高和材积的预期遗传增益分别达到11.57%、17.35%和52.06%。GXPX和GXLZ 2个种源,PX01、LZ03、PX02、DB08、PX10、PX04、PX09、DB07、DB16、LZ05、JX16和PX05等12个家系是选出的综合生长表现最好的优良种源和家系,可作为米老排良种材料进行申报并推广。  相似文献   

13.
In the last decades, several studies have reported the increase of land degradation and desertification in the Mediterranean Basin. Depending on degradation severity, ecological restoration might be needed in order to promote ecosystem recovery. The ecology of the selected species and intra specific variability should be considered in order to improve restoration options, especially facing climate change.The present study tested the hypothesis that seedlings from drier provenances would be better adapted to low water content conditions. Seeds were germinated under controlled temperature after which seedlings were grown in a phytotron under two contrasting watering regimes. Seedling performance was analysed using morphological and physiological parameters.Low water content had a clear negative effect on the seedlings’ aboveground biomass (total dry weight, root collar diameter, leaf dry weight and leaf weight ratio) and a positive effect on belowground biomass (root weight and root:shoot ratio). This response was not unequivocal, since provenances differed in morphological adaptations to low water content. Seedlings from the wettest provenance revealed a higher relative growth rate under high water content but a poor adaptation to limited water availability when compared to the other two provenances. This was observed by the absence of a significant belowground investment in this provenance. Seedlings from the wettest provenance also presented a significant reduction of total leaf area that was not observed in the other two provenances. This can however be hardly considered as a successful adaptation to cope with drought since this provenance produced less sclerophyllous leaves, less belowground biomass and also lower sapwood to leaf area ratio independently from the water content conditions. By contrast, seedlings from the dry provenance with the hottest summer had similar root collar diameter, leaf dry weight and physiological performance under both watering regimes.The observed adaptations to water regimes seem to be related with the climate of the seed source and highlighted the importance of seed provenance in ecological restoration actions using Mediterranean species. This knowledge could improve early establishment success predictions for different plant populations, allowing more reliable and cost-effective management decisions under climate change scenarios.  相似文献   

14.
Regeneration of northern conifer forests is commonly performed by reforestation with genetically improved materials obtained from long-term breeding programs focused on productivity and timber quality. Sanitary threats can, however, compromise the realization of the expected genetic gain. Including pest resistance traits in the breeding programs may contribute to a sustainable protection. Here we quantified the variation in different components of resistance of Norway spruce to its main pest, the pine weevil Hylobius abietis. We followed insect damage in two large progeny trials (52 open-pollinated families with 100–200 individuals per family and trial) naturally infested by the pine weevil. Pine weevils damaged between 17 and 48% of the planted seedlings depending on the trial and year, and mortality due to weevil damage was up to 11.4%. The results indicate significant genetic variation in resistance to the pine weevil, and importantly, the variation was highly consistent across trials irrespective of contrasting incidence levels. Individual heritability estimates for the different components of seedling resistance were consistently low, but family heritabilities were moderate (0.53 to 0.81). While forward selections and breeding for higher resistance seem not feasible, backwards selections of the best parent trees emerge as a putative alternative to reduce weevil damage. A positive genetic correlation between early growth potential and probability of being attacked by the weevil was also observed, but the relationship was weak and appeared only in one of the trials. Overall, results presented here open the door to a new attractive way for reducing damage caused by this harmful pest.  相似文献   

15.
Summary When conducting tree breeding experiments, geneticists often assume that individuals from open-pollinated families are halfsibs. The reliability of this assumption was tested using data from enzyme electrophoresis to estimate the genetic relatedness among progeny within 22 open-pollinated families of Robinia pseudoacacia L. (black locust) and 34 open-pollinated families of Gleditsia triacanthos L. (honey locust) from natural stands. An algorithm employing population estimates of fixation indices, pollen allele frequencies, and selfing rates was used to calculate the mean expected number of alleles in common across loci under assumptions of either full-sib (i.e., a single pollen parent) or half-sib (i.e., random mating) relationships. For each open-pollinated family, the average coefficient of relationship among progeny was calculated by linear interpolation from the observed number of alleles in common. For most families of both species, coefficients were significantly higher than 0.25 (half-sib relation), but were significantly lower than 0.50 (full-sib relation). These results suggest that the assumption of a half-sib relationship among progeny of open-pollinated families is violated for these tree species. More critical to the estimation of heritabilities and the prediction of genetic gains was the observation that estimates of the coefficient of relationship varied widely among open-pollinated families (for R. pseudoacacia r 0=0.20–0.43, mean=0.34; for G. triacanthos r 0=0.29–0.55, mean=0.36).  相似文献   

16.
Genetic differences in individual-tree biomass partitioning, growth efficiency, and stem relative growth rate (RGR) could confer intraspecific productivity differences and might strongly influence forest ecosystem carbon storage. We examined the relationship between genotype productivity (stem volume), whole-tree biomass partitioning, growth efficiency (stem wood production per unit leaf area), and stem RGR among nine different loblolly pine (Pinus taeda L.) genotypes from three different genetic groups of contrasting inherent genetic homogeneity: three open-pollinated (half-sib) families, three mass-control pollinated (full-sib) families, and three clonal varieties. We hypothesized that genotype productivity would be positively associated with increased partitioning to stem wood relative to other plant parts, higher stem RGR, and enhanced growth efficiency. After 3 years under plantation conditions, genotypes showed significant differences in stem volume, percent stem wood, percent branch wood, and partitioning to fine roots, yet no differences in stem RGR or growth efficiency. Furthermore, genotypic differences in stem volume were independent of genotypic differences in biomass partitioning, and overall, we found no evidence to support the hypothesized relationships. Even so, the observed variation in biomass partitioning has implications for forest C sequestration as genotypes which partition more biomass to long-lived biomass pools such as stems, may sequester more C. Moreover, the lack of a genetic relationship between stem volume and belowground partitioning suggests that highly productive genotypes may be planted without compromising belowground C storage.  相似文献   

17.
Conventionally, local seed sources are normally believed to perform better than introduced materials. However, studies show possibility of contrary results with many species such as Acacia senegal. The species is an economically and ecologically important tree of arid and semi‐arid lands of sub‐Saharan Africa. It produces gum arabic, used in land reclamation and agroforestry production. The species is however underutilized in Kenya due to lack of information on growth performance of different seed sources. Glasshouse provenance trial using seeds and soils from seven provenances in Kenya were used to evaluate interactions between seed sources and soils on growth and biomass. Seedling growth was assessed for 12 weeks in a randomized complete block design. Seed length, width, thickness and weight were measured. Seedlings height, root collar diameter, root dry weight, shoot dry weight and biomass were assessed and data subjected to univariate and multivariate analyses. No significant interaction between seed provenance and soils were evident; however, some provenances performed better across all the soils. Significant heritability and relationship between growth and environmental factors are reported. Overall, Ntumburi and Ngarendare provenances showed superior growth and plasticity. These provenances can be used tentatively as seed sources; however, field trials are recommended.  相似文献   

18.
为选择短枝木麻黄(Casuarina equisetifolia)的优良家系,对来自10个国家23个种源109个家系的短枝木麻黄生长性状进行综合选择。结果表明,造林42个月后短枝木麻黄的树高、胸径、单株材积、抗虫性、健康状况和保存率在种源和家系间均存在极显著或显著差异。印度种源(18118)、中国种源(18267、18268和18586)、泰国种源(21199、18299和18297)在生长速度上表现较好;肯尼亚种源(18144、18142、18135)、澳大利亚种源(17862)、瓦努阿图种源(18312和18565)的抗虫性较好;瓦努阿图种源(18312)和肯尼亚种源(18142)的健康状况表现较好;中国种源(18586)、越南种源(18128)和肯尼亚种源(18144)的保存率较高。单株材积的遗传力最高,保存率和抗虫性的较低,健康状况的最低。利用单株材积、抗虫性、健康状况和保存率进行指数选择,按25%的入选率,28个综合性状优良的家系可作为下一步杂交育种的遗传材料。  相似文献   

19.
Provenance variation and genetic parameters for wood properties of mature radiata pine (Pinus radiata D. Don) were studied by sampling three provenance/progeny trials in southeast Australia. Among the mainland provenances, Monterey and Año Nuevo had higher density and modulus of elasticity (at one site) than Cambria. Basic density and predicted modulus of elasticity (MoE) for the island provenances, Guadalupe and Cedros, were ~20% higher at Billapaloola compared to mainland provenances grown at Green Hills and Salicki, differences that may or may not be linked to site differences. Heritability estimates of density, predicted MoE and microfibril angle were significant and $ {\bar{h}^2} $ ?>?0.45, suggesting moderate to strong genetic control. The estimated genetic correlations between diameter at breast height and wood properties in the current study were weaker (less negative) than the mean estimated from the current breeding population generation in radiata pine. Of the wood properties, density showed the strongest adverse genetic correlations with growth (mean r A ?=??0.23?±?0.09). Selection for MoE may produce greater gain than selection for density because MoE had almost twice the estimated additive genetic coefficient of variation ( $ {\overline {\text{CV}}_A} $ ) compared to density. Estimated type B genetic correlations (r B) for all wood quality traits were typically high, conforming to the trend that wood properties have low genotype-by-environment interaction (G?×?E). Significant differences in wood properties among provenances, families and/or individual trees provide an opportunity for breeding programmes to select superior trees for solid wood production that will combine superior growth with desirable wood traits.  相似文献   

20.
Increased drought severity is expected in the Mediterranean Basin over the twenty-first century, but our understanding of the potential of most forest tree species to cope with it remains uncertain. In this study, (1) we examined the potential effects of long-term selection and the capacity to respond to future changes in selective pressures in three populations of cork oak (Quercus suber L.). For this purpose, we evaluated the response to dry conditions of 45 open-pollinated trees originating from populations in Morocco, Portugal, and Spain. Growth, leaf size, specific leaf area (SLA), carbon isotope discrimination (Δ13C), leaf nitrogen content (Nmass), and total chlorophyll content (Chlmass) were measured in 9-year-old plants. (2) We also investigated the relationships between functional traits and aboveground growth by regression models. Plants presenting larger and more sclerophyllous leaves (low SLA and high leaf thickness) exhibited higher growths, with results suggesting that these traits are subjected to divergent selection in this species. Heritability estimates were moderately high for Δ13C (0.43 ± 0.25–0.83 ± 0.31) and stem diameter (0.40 ± 0.15–0.71 ± 0.28) for the tree populations. For the rest of the traits (except for annual growth), heritability values varied among populations, particularly for height, leaf size, leaf thickness, and Nmass. Our results suggest that natural selection has led to local adaptations and has also affected the genetic variance intrapopulation in these cork oak populations, although studies with a higher number of populations should be carried out across different years. Additionally, the absence of significant genetic correlations and the fact that correlated traits did not undergo opposing selection provided little evidence for constraints on evolution caused by genetic correlations.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号