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1.
We implemented a regression-based method between pairwise relatedness estimated from markers and phenotypic similarity to estimate heritability of traits related to leaf size and morphology in a wild tree population (Vitellaria paradoxa C.F. Gaertn.: shea tree). We then compared the results with heritability estimated with a classical pedigree-based method. We tested both approaches in an agroforestry population of this tree species, a very important one and abundant in the Sudano-Sahelian zone of Africa. Twelve microsatellite loci were used to estimate pairwise relatedness after selection of estimator coefficients based on Monte Carlo simulation. The regression-based method applied to 200 individuals did not display a significant trend with physical distance between trees for relatedness as well as for actual variance of relatedness. In consequence, estimates of narrow-sense heritability of traits related to leaf size were not significant. The pedigree-based method using a progeny test with 39 families and 15 individuals per family from the same population showed high and significant estimates of narrow-sense heritability for the same traits (h2 = 0.36–0.95), demonstrating a marked genetic variation within the population. This discrepancy between methods stresses the poor performance of the molecular marker-based method. This can be explained by the absence of fine-scale structure within the agroforestry population of shea trees, other parameters being consistent with recommended values. The regression-based method does not seem well adapted to the agroforestry tree population. New experiments in tree populations and theoretical approaches are needed to evaluate the real potential of the marker-based methods.  相似文献   

2.
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3.
Vitellaria paradoxa C. Gaertn. (shea butter tree) is an indigenous African tree species that is widely distributed in the dry areas of northern and eastern Uganda. The species is widely known for its oil which is used in cooking, cosmetics and traditional medicine. Local folk classification recognises the presence of different ethno-varieties on the basis of fruit and nut characters. In the present study, 176 trees representing 44 ethno-varieties from three farming systems of Uganda were assessed to determine the patterns of morphological variation and establish the congruence between morphological variation and folk classification. The results show high variation in pulp weight (CV = 35.9 %), stem diameter (CV = 28.48 %), fruit weight (CV = 27.81 %) and canopy diameter (CV = 26.69 %). There was a strong positive correlation between pulp and fruit weight (r = 0.963, p < 0.001), leaf length and leaf width (r = 0.652, p < 0.001) and between petiole length and leaf length (r = 0.788, p < 0.001). There was no underlying quantitative morphological structuring among the 44 ethno-varieties. Hierarchical cluster analysis using quantitative morphometric data produced three groups without clear aggregation based on ethnographic or geographic separation. However, a combination with qualitative traits as perceived by farmers provided good congruence with folk classification. Quantitative morphological data alone does not resolve any discrete forms of V. paradoxa that are related to folk classification. There is need to utilise biochemical and molecular markers to unravel the underlying variation for use in selection and improvement of shea butter tree ethno-varieties.  相似文献   

4.
In this paper, we report on morphological diversity of Amygdalus L. species native to Lebanon, following a countrywide survey of almond germplasm whereby a total of 149 accessions were collected throughout the country and characterized by thirteen quantitative and four qualitative traits. The results indicated that the genetic diversity of Amygdalus communis L., Amygdalus korshinskyi Hand.-Mazz., and Amygdalus orientalis Duh. in Lebanon is high. Principal component analysis revealed that nut weight, nut volume, nut width, kernel volume and shell strength had highest loading in the first component that accounted for 38.7% and 46.7% of total variation in A. communis and A. orientalis, respectively. In contrast, leaf traits were present in the second component which accounted for 18% and 23.2% of total variation in each species, respectively. No significant correlations were detected between leaf parameters and fruit traits in both species. The results indicated that quantitative leaf characters for all three species were determined by rainfall and not altitude whereby adjacent accessions located in drier areas had smaller leaf sizes than those located in more humid regions. Quantitative fruit characters did not seem to vary accordingly. Qualitative leaf traits in all three species reflected a variability which was independent of rainfall. A. communis populations showed high variability, suggesting that they could be a valuable source in almond improvement programs.  相似文献   

5.
Artocarpus altilis (Park.) Fosberg is an important fruit vegetable tree grown in the homesteads of southern part of India. To provide reasoned scientific management practices and conservation measures, the pattern of morphological and genetic variation were investigated for six populations using Amplified Fragment Length Polymorphism (AFLP) markers and 15 morphological traits. The use of five selective primer combinations on 60 samples resulted a total of 414 bands in which 85% were polymorphic. The values of Nei’s genetic distance varied from 0.0044 (Palai–Palghat) to 0.3376 (Palghat–Mangalore). Analysis of molecular variance revealed most of the variation within populations (57.45%) than (42.55%) among populations. The genetic variation by AFLP data is not reflected in quantitative morphological variables. However, the genetic and geographical distances were positively correlated which were further well supported by the PCO analysis and Dollo-parsimony tree, both show the tendency of the individuals to group according to the geographical localities.  相似文献   

6.
Allanblackia parviflora A. Chev. (Clusiaceae Lindley) is an indigenous tree species which is found in the rain forest regions of Ghana. It is a potential candidate fruit tree species being introduced in agroforestry systems. Information on genetic diversity, reproductive biology and fruit yield are not known. Field expeditions to seven populations of Allanblackia parviflora in Ghana were undertaken in 2003–2006 during which fruits were collected from 109 trees for characterization. The species was found to be dioecious. The colour of flowers varied from whitish to reddish. No ecological differences in number of fruits per tree, fruit shape and seed health were observed. However, large variations in fruit size and shape were observed among individual trees sampled. A high heritability (h 2 = 0.822) in fruit size and genetic gain (G = 20.1%) in fruit size for selection of trees with above average fruit size were observed. A positive significant correlation was observed between fruit size and seed weight (R = 0.54, P < 0.05; Fig. 6). The results suggest that selection and cloning of trees with large fruits could lead to higher yield of seeds for oil production.  相似文献   

7.
A total of 137 accessions from 18 wild almond species were collected from Iran and leaf and fruit traits were characterized. Also evaluated were flowering and ripening date, self-incompatibility and kernel bitterness. An extensive phenotypic diversity was found both among and within species. Differences in average leaf dimensions among and within species were associated with average rainfall but not altitude of collection site. Adjacent accessions located in drier areas had smaller leaf dimensions than those located in semi-humid or humid regions. No relation was found between average fruit dimensions and collection site conditions. Principal component analysis revealed that the nut weight and width, and the kernel weight had highest loading in the first component accounting for 45.8% of total variation. In contrast, leaf traits in the second component accounted for 22.3% of total variation. No significant correlations were detected between leaf dimensions and fruit traits in all species evaluated. Results document a rich source of new germplasm for almond improvement programs. Small fruit size, pollen-pistil self-incompatibility, and bitter kernel flavour are the most common obstacles to the utilization of this wild germplasm in breeding.  相似文献   

8.
The Sheanut tree (Vitellaria paradoxa C.F. Gaertn.) is highly valued for oil obtained from its seeds and frequently maintained in the semi-arid parklands of sub-Saharan Africa from Senegal to Uganda. Although variation has been noted for V. paradoxa subsp. paradoxa, few studies have been undertaken on patterns of phenotypic or genotypic diversity. Results are presented from 294 accessions collected in Ghana, using easily quantifiable morphological parameters. Productive mature trees varied from shrubby multi-stemmed individuals (height <5 m) to 30-m straight-boled trees with high compact canopies. The leaf lamina (tree mean ±% coefficient of variation of total mean) varied from 9.2 to 22.5 cm (±15.0%); seed length from 1.74 to 3.74 cm (±11.7%); and fat content from 29.1 to 61.9% of dry kernel weight (±9.4%). Clinal trends significantly correlated with location parameters that in turn related to environmental variation. Population variation of seed characteristics increased to the Northeast, perpendicular to the annual movement of the inter-tropical convergence zone. It is proposed that this is a consequence of past climatic changes, coupled with a lack of methodical selection for seed type when trees are maintained on agricultural land. Isozyme analysis revealed moderate to high levels of heterozygosity (He 0.2142) and high geneflow (Fst = 0.0124, Nm = 19.9), supporting results obtained from morphological studies. Isozyme and multivariate morphology analyses showed similar but weak geographical separation patterns.  相似文献   

9.
The isolated Sudanese baobab (Adansonia digitata L.) populations, located at the northernmost limit of the East African distributional range of the species, are regarded as important genetic resources. The morphological variation in fruits of selected baobab trees in Kordofan, Sudan, was evaluated by sampling fruits and assessing their characteristics. Furthermore, locations and stem diameter at breast height of 240 baobabs were mapped for a stand in Kordofan. Our preliminary results indicated a high diversity in fruit phenotypes. Ventricose, crescent-shaped, globose and fusiform fruit types were identified. Fruit shape varied between trees but was consistent within each individual tree. Percentage of fruit pulp varied between the different fruit types with 14, 15, 18, and 21 % recorded for ventricose, fusiform, crescent-shaped and globose fruits, respectively. Interesting was also the observation of baobab morphotypes that retained leaves during the dry season. Variation in leaf morphology could also be recognised. Measurements of baobab trees revealed a density of 0.72 individuals ha?1. Stem diameters ranged from 0.06 to 4.77 m. The size class distribution (SCD) showed an inverse J-shaped curve with a SCD slope of ?0.57 which indicates a viable regenerating population. Based on the results recorded, enhancement of scientific research activities on the almost unstudied baobabs in Kordofan, Sudan is highly recommended.  相似文献   

10.
The baobab tree (Adansonia digitata L.) is a valued savannah tree. Although variation in fruit characteristics of this tree have been studied, no studies to our knowledge have been carried out on variation of leaf morphology which can be linked to drought adaptation mechanisms. Accessions of baobab from different ecosystems in Benin were characterised for leaf size and thickness, stomata size and density on the abaxial surface of leaves. Significant variation was found in leaf size and stomata characteristics. Trees from northern study sites had higher stomata density and smaller guard cell length than those from southern study sites. The results show that pruning has a significant effect on leaf size, but not on stomatal characteristics. Trees from northern study sites showed more xerophytic characteristics than those from the south. It seems that genetic and physiological effects may play a role in baobab drought adaptation.  相似文献   

11.
Morphological variation of the coconut fruit measured in situ has been used to estimate genetic diversity, and generate hypotheses about the evolutionary and geographical diffusion of coconut. Some authors have questioned the validity of this methodology due to the possibly high effect of the environment on the morphological characteristics of the fruit. The general aim of this study is to validate this methodology through: (1) characterizing the pattern of morphological variation of the fruit under homogeneous growing conditions ex situ; (2) comparing this pattern with those already reported in situ; (3) estimating the heritability values for the components of fruit in coconut. Results are also discussed in comparison with ex situ leaf variation and biochemical and molecular variation patterns previously studied. Principal components and discriminant analyses indicated that the characters that best differentiate groups are basically the same in situ and ex situ. Grouping patterns obtained with principal components and cluster analysis were similar for both growing conditions. They were also similar to the grouping pattern obtained with ex situ leaf characters. No significant differences were found in the variation coefficients of fruit characters between the same populations in situ and ex situ. Consistency was found between patterns of morphological variation of fruit ex situ and in situ, and those obtained using iso-enzymatic and molecular characteristics. The results are also consistent with hypotheses on the origin and diffusion of the germplasm introduced to Mexico. High values of heritability were found in nine characters. Weight and water percentage showed the highest values (0.88 and 0.883), with a strong correlation to the mass and the roundness of fruit and seed, suggesting that human selection of these characteristics led to the differentiation of domesticated populations. We conclude that morphological characterization of the coconut fruit in situ is useful to estimate its genetic variability because of its simplicity, speed and ease of application in the field and in remote areas.  相似文献   

12.
杨梅生长指标与果实品质间的相关性分析   总被引：1，自引：0，他引：1  
为了明确成熟期不同品种杨梅(早鲜早色和东魁)的营养生长指标与果实外观、品质性状间的相互关系,在成熟采收期,分别对杨梅7个营养生长指标、10个果实外观性状和13个果实品质性状进行测定分析。结果表明,杨梅30个性状指标的变异系数范围为2.546%~31.021%,其中维生素C(Vc)含量、果实硬度(HN)和春梢长度(BL)的变异系数较大,分别为31.021%、22.092%和15.245%。糖酸比(AS)与果实色度值L*、b*、C,叶片长度(LL)、宽度(LW)、厚度(LT)显著负相关,说明通过杨梅果实颜色可以预测AS,且在AS的形成过程中杨梅LL、LW和LT发挥了重要作用;叶绿素(Chl)相对含量、HN与杨梅果实多个外观品质、营养品质指标间呈显著正相关,表明在生产上可以通过提高Chl相对含量改善果实品质;杨梅BL与果实外观品质、营养品质等13个性状均为显著性负相关,证明杨梅结果枝以中短果枝为宜。本研究结果为利用营养生长指标进行优良品质性状的选择提供了一定的理论参考。  相似文献   

13.
RAPD markers were used to investigate the distribution of genetic variability in a germplasm collection of the dioecious tropical tree Aroeira (Myracrodruon urundeuva) composed of open pollinated maternal half-sib families collected from trees at least 300 meters apart and grouped in nine collection areas throughout its geographical range in Brazil. Open pollinated families from nearby trees from two natural populations were also included in the study. A Principal Coordinate Analysis (PCO) based on genetic similarities estimated with 83 RAPD markers showed no defined clustering among individuals from the same collection areas. However, a matrix correlation test showed low, but significant correlation between genetic and geographic distances (r = 0.17; p < 0.02). An AMOVA showed that 92% of the genetic variation is found within collection areas. Significant variation was found both between regions and between areas within regions although only 3.54 and 4.44% of the variation was found at these levels respectively. An AMOVA on the individuals from the two natural populations resulted in a pattern of distribution congruent to the one found for the collection areas, with 97% of variability within populations. An analysis of 10 open-pollinated half-sib families revealed that between 75% and 89% of the variability is contained within families, suggesting that seeds from one tree represent a significant proportion of the variability found in the population. These results indicate that, either for the establishment of in situ genetic reserves or for ex situ conservation, efforts should be directed to the conservation of several individual trees or collection of open pollinated seed families in a few distant sites. In addition, if resources are available to enlarge the genetic base of the existing collection, expeditions should prioritize collection sites located in areas at significant distances to those already sampled.  相似文献   

14.
Thaumatococcus daniellii is a perennial African wild edible plant. Fruit arils from natural populations are the source of the protein sweetener, thaumatin. There are relatively few documented examples of its cultivation, however it has great potential as an intercrop for cultivation under rubber or cocoa. Across the species range there is notable diversity in leaf and fruit morphology. In this study, T. daniellii populations from four provenances in Ghana and Cameroon (separated by the Dahomey Gap) were compared for leaf and fruit morphology in situ and in an experiment using plants grown from sampled rhizomes planted under rubber in a single location in Cameroon. When collected rhizomes from four provenances were planted at one location, the samples from the local provenance produced the largest plants and fruits, and there was less morphological variation between samples from different provenances than was recorded in situ. In situ morphological differences were notable between north–south separated provenances in each country. Fruit collected in situ was analysed for aril thaumatin content and significant variation was found between provenances (1.08–2.00%). Amplified fragment length polymorphism (AFLP) was used to assess genetic diversity among the four provenances and 54% of loci were polymorphic. Cluster analysis of AFLP data separated samples of T. daniellii according to geographical origin. Maximum genetic diversity was found between provenances separated across the Dahomey Gap.  相似文献   

15.
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16.
Tamarind (Tamarindus indica L.) is a tropical fruit tree highly valued for its fruit pulp. It has been identified as one of the priority species with great potential for domestication in the Sahelian countries of Sub-Saharan Africa. An important step in the domestication process is the characterization of the local natural variation of the species in order to select the most interesting phenotypes/genotypes which possess several desired traits for breeding purposes. Four provenances covering contrasting agro-ecological zones in Mali were selected for fruit morphological and nutritional traits (tartaric acid and sugars). Tamarind trees from the driest provenance contained smaller fruits with a smaller amount of pulp compared to provenances from wetter zones. Tamarind trees in Mali have a low real pulp value (maximum 9.5) and bear sour fruits (high tartaric acid content of 9–12 %). Some sweet-fruited trees could be identified, but the sweetness was low (maximum 8). Fruit traits seem to be influenced by climate and soil characteristics, which should be taken into account in the domestication process, when planting trees in a different region of origin. We selected a few elite trees within each provenance, containing the best combination for the most desirable fruit traits, using web diagrams. Frequency distributions of the different fruit traits showed some traits are probably the target of selection by farmers. All provenances, except the driest one, indicated a possible very first stage of domestication.  相似文献   

17.
Jacaratia mexicana A. DC. (Caricaceae) is a tropical tree distributed throughout Mexico and Mesoamerica. Some evidence in Mexico indicates the presence of an incipient domestication process in this species. Phylogeographical analyses can potentially determine contemporary patterns of gene flow, isolation between population lineages, as well as historical processes such as population bottlenecks or expansions on their geographical areas. In this study we reconstruct the phylogeographical patterns in populations of J. mexicana A. DC., in order to find differences between genetic variation among wild and cultivated populations utilizing chloroplast DNA and nuclear DNA sequences. We generate a Bayesian phylogenetic tree, to estimate the divergence time between clades using calibrated mutation rates. We also infer the demographic history of these populations using neutrality tests among wild and cultivated accessions. We identified higher levels of haplotype and nucleotide diversity for the cpDNA and ITS types in wild populations than in domesticated populations. These results indicate a reduction of genetic diversity derived from human selection on domestication traits. Neutrality test suggests population expansion detected by the significant negative values of Fu’s Fs in the cultivated populations of this specie. These process results in an excess of rare polymorphism with the fixation of certain advantageous mutation throughout time, this implication are in accordance with the role of the strong selection in the fruit traits of J. mexicana. The dated phylogeny constructed with BEAST program indicated a dispersion pattern for the J. mexicana ancestors across the South Pacific and South Eastern populations during the late Pliocene. Posterior dispersion and divergence in the clades from Central Mexico and North Pacific are in agreement with the episodes of mountain-building in different regions of Mexico.  相似文献   

18.
An understanding of variation in fruit quality in relation to tree age can help understand the issue of poor fruit quality in young orchards; however, limited information is available on the citrus fruit. In this study, the endogenous nutritional status in rind, rag, and leaves; pectin status in rind and rag; and anatomical fruit growth parameter in rind tissues were studied in ‘Kinnow’ mandarins fruit during their development on trees from three age (6-, 18-, and 35-year-old) groups. In older (35-year-old) trees, rind, rag, and leaf nitrogen (N), phosphorus (P), and potassium (K) concentrations were superior. In fruit from all tree age groups, total pectin and protopectin reduced; however water-soluble pectin (WSP) improved. In rind tissues harvested from young (6-year-old) trees, cell density was more while cell size was less. In all tree age groups, cell density in rind tissues correlated negatively with rind WSP.  相似文献   

19.
We investigated morphological evidence that might allow wild Pyrus spp. to be distinguished from cultivated material (Pyrus communis L.) in the North-eastern Iberian Peninsula. 134 pear trees were identified in the wild and characterized by 13 quantitative and 13 qualitative leaf–shoot and fruit traits. The trees were visually classified into two preliminary groups of wild and cultivated material and discriminant functions, based on a reference collection for allocating individuals to one of the groups, were constructed. Both classifications were compared with a near-optimal numerical classification (the two-stage Ward-MLM strategy) using two criteria. The visual assignment of trees allocated 60% of trees to the wild group and 40% to the cultivated group. The overall discrepancy rate between the field classification and the discriminant analysis was low (17.4%). In general, wild individuals had smaller leaves, shorter petioles and more rounded and smaller fruits than their cultivated counterparts. They also had small-to-intermediate petiole widths, thorns on their shoots and straight or convex fruit profiles. However, the Ward-MLM strategy always formed better groups, in terms of the two criteria used, in all the continuous and categorical variables, for both leaf–shoot and fruit traits. Likewise, the agreement between classifications (discriminant analysis and Ward-MLM strategy) was only partial, with some Ward-MLM groups composed of both wild and cultivated material in similar proportions. This result suggests a limited success in identifying genuine wild individuals based on morphometric data, which can be ascribed either to poor phenotypic diversity and lack of distinguishing traits among species or to widespread crossability and subsequent development of hybrid/introgressant populations between wild and cultivated specimens.  相似文献   

20.
The umbu tree (Spondias tuberosa) is a xerophytic woody species endemic to the northeast of Brazil. The present work reports a three-year in situ evaluation of major yield components in a random set of trees in Petrolina city, Pernambuco State, Brazil and the application of repeatability coefficient in the context of genetic resources utilization. Five traits were assessed: total fruit yield per plant (FY); total number of fruits per plant (NF); average fruit weight (FW); average pulp weight (PW) and average fruit diameter (FD). The values observed for FY ranged from 4.2–184 kg with mean of 61.5 kg. The values for NF ranged from 257 to 12,981 fruits/tree with mean 3,993 fruits. For FW, the range was from 10.82–23.36 g with mean of 16.03 g. The values for PW ranged from 7 to 17 g with mean of 11.2 g, while FD values varied from 2.5 to 3.5 cm with mean of 3.0 cm. Six methods were employed to estimate repeatability coefficient (r) for all parameters. The r ranged from 0.68–0.76 for NF; 0.87–0.89 for FW; 0.65–0.75 for FY; 0.64–0.78 for PW and 0.70–0.84 for FD. Narrower ranges across methods were observed to r-values greater than 0.80, as observed for FW and FD. Three to four years of measurements will be necessary for FY, NF, and PW and one year for FW to obtain a precision of 90% to provide a reliable identification of individuals for in situ or ex situ conservation.  相似文献   

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