Relationships of Vigna unguiculata (L.) Walp., V. vexillata (L.) A. Rich. and species of section Vigna based on isozyme variation

Summary Isozyme variation in 25 accessions of wild and cultivated Vigna unguiculata, 49 accessions of seven wild species belonging to section Vigna, and 11 accessions of V. vexillata (subgenus Plectrotropis) was scored at 17 putative loci to assess genetic relationships within and among species. The wild species selected for this study are among those which carry important agronomical traits useful in cowpea (V. unguiculata) breeding programs. Allelic frequencies were calculated and Nei's genetic distances were obtained. Low levels of intraspecific variation were observed for V. heterophylla, V. luteola and V. racemosa, whereas the other species showed a higher polymorphism. Vigna unguiculata possessed intraspecific genetic distances comparable to those previously found by other authors. Most of the isozyme variation was apportioned among species. Although V. luteola and V. marina had an interspecific genetic distance resembling the range observed at intraspecific level, all the other species showed very high interspecific distances. Vigna unguiculata was relatively closer genetically to V. vexillata than to the species belonging to section Vigna.Abbreviations AUS Australia - BDI Burundi - BRA Brazil - BWA Botswana - CAF Central African Republic - GHA Ghana - CMR Cameroon - COG Congo - RI Costa Rica - EGY Egypt - ETE Ethiopia - GAB Gabon - GRC Greece - ITA Italy - KEN Kenya - MOZ Mozambique - NER Niger - NGA Nigeria - PAN Panama - RWA Rwanda - TCD Chad - TZA Tanzania - ZAF South Africa - ZAR Zaire - ZMB Zambia     

Genetic variations and interrelationships in Vanilla planifolia and few related species as expressed by RAPD polymorphism

Vanilla is naturally distributed in Mexico and parts of Central America and the history of origin of cultivated vanilla suggests that the entire stock outside Mexico may be from a single genetic source. In the present study, RAPD polymorphism was used to estimate the level of genetic diversity and interrelationships among different collections of Vanilla planifolia Andr., and few related species, including both leafy and leafless types such as V. tahitensis J.W.Moore, V. andamanica, Rolfe, V. pilifera Holtt., and V. aphylla Blume. Studies revealed that there are very limited variation within collections of V. planifolia, indicative of its narrow genetic base, and of the related species we tested, V. tahitensis is nearest to V. planifolia. The species studied are diverse and have a similarity ranging from 1.2 to 57.3 %. Of the sampled taxa, V. andamanica is the most divergent and there is also reasonable variability within its collections, indicating the possibility of natural seed set. A total of 82 polymorphic bands expressed in the RAPD profiles were used to generate a genetic distance matrix, which was then used in cluster analysis. Specific groupings were revealed by the cluster analysis whereby the leafless forms (V. aphylla, V. pilifera and the new species) and V. andamanica formed separate clusters. This is the first report of species interrelationship studies, including both cultivated and wild vanilla species.     

Analysis of population substructure,genetic differentiation and phylogenetic relationships among selected Asiatic <Emphasis Type="Italic">Vigna</Emphasis> Savi species

Random amplified polymorphic DNA markers were used to study sub-structure and genetic differentiation amongst 31 populations (seven cultivated and 24 wild populations) belonging to 14 Asiatic Vigna species. Ten pre-selected RAPD primers generated 152 polymorphic amplification products. Estimates of polymorphism indices were higher for the wild taxa in comparison to the cultivated forms. F_ST values between populations ranged from 0.111 to 0.801 and Nei’s genetic diversity values between and within species varied from 0.26 to 0.70 and 0.04 to 0.56 respectively. The high F_ST and F_CT values indicated strong subdivision of populations and high differentiation among species. Analysis of molecular variance was performed by grouping the populations conforming to specific species. AMOVA was also performed separately to better resolve the differentiation of species within mungo–radiata complex. Molecular phylogenetic relationships amongst the species of radiata–mungo complex; namely, black gram (V. mungo (L.) Hepper), green gram (V. radiata (L.) Wilczek), V. radiata var. sublobata, V. radiata var. setulosa, V. mungo var. silvestris and V. hainiana, were studied through cluster analyses. Two distinct groups were recognized within the complex, with population samples of V. hainiana forming one cluster. Further, V. hainiana appeared to be equidistant to both V. radiata and V. mungo.     

Diversity and genetic resources of wild <Emphasis Type="Italic">Vigna</Emphasis> species in India

Diversity in morphological characters of 206 accessions of 14 wild Vigna species from India was assessed. Of these, 12 species belonged to Asian Vigna in the subgenus Ceratotropis and two were V. vexillata and V. pilosa belonging to subgenus Plectotropis and Dolichovigna, respectively. Data on 71 morphological traits, both qualitative and quantitative, were recorded. Data on 45 qualitative and quantitative traits exhibiting higher variation were subjected to multivariate analysis for establishing species relationships and assessing the pattern of intraspecific variation. Of the three easily distinguishable groups in the subgenus Ceratotropis, all the species in mungo-radiata group, except V. khandalensis, viz. V. radiata var. sublobata, V. radiata var. setulosa, V. mungo var. silvestris and V. hainiana showed greater homology in vegetative morphology and growth habit. The species, however, differed in other plant, flower, pod and seed characteristics. Within species variation was higher in V. mungo var. silvestris populations and three distinct clusters could be identified in multivariate analysis. V. umbellata showed more similarity to V. dalzelliana than V. bourneae and V. minima in the angularis-umbellata (azuki bean) group. Within species variations was higher in V. umbellata than other species in the group. In the aconitifolia-trilobata (mothbean), V. trilobata populations, were more diverse than V. aconitifolia. The cultigens of the conspecific wild species were more robust in growth, with large vegetative parts and often of erect growth with three- to five-fold increase in seed size and seed weight, except V. aconitifolia, which has still retained the wild type morphology to a greater extent. More intensive collection, characterisation and conservation of species diversity and intraspecific variations, particularly of the close wild relatives of Asian Vigna with valuable characters such as resistance to biotic/abiotic stresses, more number of pod bearing clusters per plant etc. assumes great priority in crop improvement programmes.     

The introgression of 2× 1EBN <Emphasis Type="Italic">Solanum</Emphasis> species into the cultivated potato using <Emphasis Type="Italic">Solanum verrucosum</Emphasis> as a bridge

Wild diploid Solanum species with an endosperm balance number (EBN) of one are a rich source of disease resistance, pest resistance, and tuber quality traits. They are not sexually compatible with 4× 4EBN or 2× 2EBN forms of the cultivated potato. In this study, the wild 2× 2EBN Mexican species S. verrucosum (ver) was used as a bridge species to access 2× 1EBN germplasm. Hybrids (V1) were created between ver as a female parent and the 1EBN species S. cardiophyllum, S. chancayense, S. commersonii, and S. trifidum. Most of the V1 hybrids were successfully crossed as females to cultivated 2× 2EBN clones. However, due to stylar barriers, reciprocal crosses were unsuccessful. Additional studies are underway to determine the effectiveness of ver as a bridge to introgress specific traits from 2× 1EBN germplasm into the cultivated potato.     

Intergeneric relationships in the Australian Vitaceae: new evidence from cpDNA analysis

Taxa related to important agricultural species are likely to contain a considerable amount of potentially valuable genetic diversity. Nevertheless, before breeding programs or gene discovery projects can be initiated it is important to understand the phylogenetic relationships between the species involved. A component of a major gene discovery project in grapes at the Centre for Plant Conservation Genetics (Southern Cross University, Australia) is directed at the discovery of novel genes in native Vitaceae. As a result a study was conducted in order to assess the phylogenetic relationships between V. vinifera and the native members of the three major Australian genera: Cayratia, Cissus and Tetrastigma. CpDNA sequence analysis (from the trnL intron) adequately resolved intergeneric relationship between the majority of the species studied and provided some useful new information on the phylogenetic relationships within the Vitaceae. This preliminary project identified two species, C. hypoglauca and C. sterculiifolia, as being closely related to V. vinifera and worthy of further in-depth investigation.     

Genetic Diversity of the Vigna Germplasm from Thailand and Neighboring Regions Revealed by AFLP Analysis

Thailand is a center of diversity for section Angulares of the Asian Vigna (genus Vigna subgenus Ceratotropis) and 4 Vigna species are cultivated in Thailand. Using newly collected wild and cultivated germplasm of Vigna from Thailand and outgroup accessions AFLP analysis was conducted to clarify genetic diversity and relationships. The results suggest that cultivated V. umbellata and V. mungo evolved from wild relatives in a single domestication event. Vigna umbellata is poorly differentiated from its wild and weedy relatives compared to V. mungo. Results suggest northern Thailand and the neighboring Shan state, Myanmar, is the probable center of domestication for V. umbellata as wild accessions from this area and cultivated rice bean from a wide area in Asia are not greatly diverged. Vigna minima, V. tenuicaulis and V. exilis accessions in Thailand are well differentiated with considerable intra-specific variation. Vigna hirtella consists of two well differentiated subgroups, suggesting taxonomic revision may be necessary. Close genetic relationships between V. radiata and V. grandiflora, and between V. mungo and V. trinervia are confirmed. Naturally growing V. mungo populations in northern Thailand appear to be true wild species as they are well differentiated from Indian wild and Thai cultivated populations. The origin of naturally growing cowpea in Thailand needs to be further studied using a more comprehensive set of materials. This study clarifies inter and intra-specific genetic diversity and inter species relationships of Thai Vigna species.     

Phosphate-solubilizing microorganisms associated with the rhizosphere of mangroves in a semiarid coastal lagoon

 The phosphate-solubilizing potential of the rhizosphere microbial community in mangroves was demonstrated when culture media supplemented with insoluble, tribasic calcium phosphate, and incubated with roots of black (Avicennia germinans L.) and white [Laguncularia racemosa (L.) Gaertn.] mangrove became transparent after a few days of incubation. Thirteen phosphate-solubilizing bacterial strains were isolated from the rhizosphere of both species of mangroves: Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus atrophaeus, Paenibacillus macerans, Vibrio proteolyticus, Xanthobacter agilis, Enterobacter aerogenes, Enterobacter taylorae, Enterobacter asburiae, Kluyvera cryocrescens, Pseudomonas stutzeri, and Chryseomonas luteola. One bacterial isolate could not be identified. The rhizosphere of black mangroves also yielded the fungus Aspergillus niger. The phosphate-solubilizing activity of the isolates was first qualitatively evaluated by the formation of halos (clear zones) around the colonies growing on solid medium containing tribasic calcium phosphate as a sole phosphorus source. Spectrophotometric quantification of phosphate solubilization showed that all bacterial species and A. niger solubilized insoluble phosphate well in a liquid medium, and that V. proteolyticus was the most active solubilizing species among the bacteria. Gas chromatographic analyses of cell-free spent culture medium from the various bacteria demonstrated the presence of 11 identified, and several unidentified, volatile and nonvolatile organic acids. Those most commonly produced by different species were lactic, succinic, isovaleric, isobutyric, and acetic acids. Most of the bacterial species produced more than one organic acid whereas A. niger produced only succinic acid. We propose the production of organic acids by these mangrove rhizosphere microorganisms as a possible mechanism involved in the solubilization of insoluble calcium phosphate. Received: 21 April 1999     

Genetic relationships among cultivated and wild <Emphasis Type="Italic">Vigna angularis</Emphasis> (Willd.) Ohwi et Ohashi and relatives from Korea based on AFLP markers

Genetic variation and relationships among members of the azuki bean complex (Vigna angularis) including wild (V. angularis var. nipponensis), weedy, and cultivated types (V. angularis var. angularis), V. nakashimae, and rice bean (V. umbellata) from Korea were examined using the Amplified fragment length polymorphism (AFLP) method. AFLP analysis of 50 accessions revealed 333 (72.1%) polymorphic fragments out of 462 fragments amplified using seven primer combinations. The number of polymorphic fragments within each species was 70 in the azuki bean complex and 41 in V. nakashimae, but there was no polymorphism in rice bean. The number of shared fragments among species ranges from 142 between the azuki bean complex and V. nakashimae to 166 between the azuki bean complex and rice bean. Within the azuki bean complex, the range of shared bands was from 231 between cultivated and weedy types to 238 between cultivated and wild types. A dendrogram generated from Jaccard’s similarity matrix was divided into three groups, which correspond to V. nakashimae, azuki bean complex, and rice bean. The relationship between azuki bean and rice bean is closer than between azuki bean and V. nakashimae. Phenetic distances averaged 0.502 between the azuki bean complex and V. nakashimae and 0.467 between the azuki bean complex and rice bean. Within the azuki bean complex, the weedy type was more closely related to wild than cultivated types. But UPGMA dendrogram of the azuki bean complex reveals that each type is not clearly isolated. These results will help to understand genetic diversity and evolutionary dynamics of Vigna in Korea.     

Genetic variation analysis in the genus Lathyrus using RAPD markers

RAPD analysis was applied to five species belonging to the genusLathyrus (Fabaceae): L.sativus, L.cicera, L.ochrus, L.sylvestris and L.latifolius. All the species under study belong to thesection Lathyrus except L.ochrus which is in section Clymenum.Nine populations representing these species were used and ten random10-mer primers were sampled. A total of 129 amplification products,ranging in size from 0.3 to 3 Kb, were generated. Partitioning ofvariation was studied using the AMOVA technique. The genetic variation proved tobe nearly equally distributed among species and among populations withinspecies. A similar approach was carried out to distinguish populations, whichproved to be efficient. The between population dissimilarities were calculatedand a dendrogram of genetic relationships was drawn. The RAPDs obtained weresufficient to distinguish between the two accessions of a species and toseparate these accessions by clustering them according to species. A highgenetic similarity between the populations of L.sylvestris and L.latifolius was established. A similar result is also shownfor the populations of L. sativus andL. cicera.     

Resistance to α‐Amylase Digestion in Four Native High‐Amylose Maize Starches

Native and processed high‐amylose maize starch (HAMS) is an important source of resistant starch (RS). The objectives of this work were to use an in vitro procedure to estimate the RS content of native granules from a series of ae‐containing HAMS genotypes, and to examine the nature of the α‐amylase resistant starch (ARS). By the method of Englyst et al (1992), RS for ae V, ae VII, ae su2, and ae du were estimated to be 66.0, 69.5, 69.5, and 40.6%, respectively. By transmission electron microscopy, most of the residual granules from ae V, ae VII, and ae su2 showed little evidence of digestion. Partially digested granules had a radial digestion pattern in the interior and an enzyme‐resistant layer near the surface. Size and chain‐length profile of constituents of ARS were similar to those of the native HAMS (unlike type 3 RS), consistent with complete hydrolysis in susceptible granule regions. Between crossed polarizers, many iodine‐stained native and residual HAMS granules had blue centers and pink exteriors, which may be due to a difference in orientation of the amylose‐iodine complexes in the exterior. Four granule color types were observed for ae du, differing in enzyme resistance. The high‐enzyme resistance of native HAMS granules may result from altered granule organization, which appears to vary among and within granules from ae‐containing genotypes.     

Nutritional characteristics of mineral elements in tree species of tropical rain forest,West Sumatra,Indonesia

The nutritional characteristics of mineral elements in tree species were studied in a 1 ha permanent observation plot at Mt. Gadut area near Padang, West Sumatra, Indonesia. The elemental composition of the 42 leaf and the 457 bark samples from the 1 ha plot was analyzed. Most of the elements, such as S, K, AI, CI, Si, B, and Sr, showed a significant correlation between leaf and bark, suggesting that bark can also be used to study the nutritional characteristics of trees instead of leaves as the first approximation. The concentrations of elements in 457 bark samples showed a wide range, indicating the considerable diversity of nutritional characteristics of mineral elements among these tree species. The concentration ranges expressed in mg kg-¹ were Mn (0.1–3,800), Sr (0.1–1,070), Si (2–1,700), Fe (0.6–4,100), Al (10–46,000), Mg (10–7,200), Zn (0.4–290), K (60–22,000), Cu (0.8–150), P (19–2,540), CI (110–9,200), S (170–13,600), Ca (2,300–100,000), B (4–70), and N a (130–700). Accumulator species were defined as trees with concentrations higher than logarithmic mean + 2std., whereas excluder species were defined as trees with concentrations lower than logarithmic mean — 2std. Among the 113 tree species identified, the accumulators were A. maingayi, M. glaberrimus, M. laurinum, P. axillaris, S. javensis, and M. sericea for S, A. frutescens, A. maingayi, M. laurinum, M. corymbosus, and E. acuminata for Al, F. ribes for Ca, B. pendula and U. maerophyllum for Cl, M. affinis and M. sereea for Si, M. affinis, L. elegans, G. maerophyllum, C. seorteehinii, and E. decipiens for Na, G. macrophyllum, E. opaea, E. latifolia, and C. arborea for B, E. opaea for Cu, F. lepicarpa for Fe, G. maerophyllum and E. opaea for P, A. malaccensis for Zn. The excluders were L. conoearpus for S, V. umbonata, L. conocarpus, S. elongata, G. forbesii, and M. serieea for Al, V. umbonata, L. conocarpus, P. grandis, P. eaeruleseens, G. forbeii, and H. arthoearpoid for Ca, V. perakensis, L. conocarpus, C. seorteehinii, and P. grandis for Mg, V. perakensis, B. tokbrai, C. zollingeriana, G. forbesii, and E. fastigiata for Na, P. exeelsa for Cu, A. porteri for Fe, P. alnifolia for Mn, L. conocarpus and G. forbesii for Sr. Specific Al accumulators were observed. M. corymbosus and U. macrophyllum accumulated Al at very high concentrations, 40 and 20 g kg-¹, respectively. Moreover, Al was accumulated not only in the mature leaves but also in the new leaves. A significant correlation between Al and P concentrations in the 457 bark samples was also observed. These observations suggest that Al exerts a beneficial effect on plant growth for certain tree species in the plot by stimulating P absorption.     

Genetic relationships among perennial and annual Cicer species growing in Turkey as revealed by allozymes

Allozyme polymorphisms were used to assess genetic variation and relationships among ten Cicer species (annuals and perennials) growing in Turkey. Using seven enzyme systems, 12 putative scorable loci were detected and surveyed for polymorphism in an accession collection including wild and cultivated forms. Variation was generally low within accessions and species, but common between species. Cluster analysis based on the pairwise genetic distance coefficients among accessions and species using UPGMA revealed two species clusters; one includes three perennials (C. montbretii, C. isauricum and C. anatolicum) and the other contains six annuals (C. pinnatifidum, C. bijugum, C. judaicum, C. echinospermum, C. reticulatum and C. arietinum) and one perennial species (C.incisum). Grouping obtained in allozyme analysis appears to be consistent with the classification these species into three sections. However, contrary to relationships obtained in previous studies, three perennial species from section Polycicer were relatively distant to the group containing annuals. One perennial species, C. incisum from section Chamaecicer, clustered with annuals showing a close similarity. The grouping of six annual species was consistent with the previous reports of relationships. The relationships deduced between perennials and annuals appear to shed light on the evolution of annual habit from perennial habit.     

The effect of mesoclimate on Collembola diversity in the Zádiel Valley, Slovak Karst (Slovakia)

In 2002–2004 an investigation of Collembola communities in the Zádiel Valley (Slovak Karst, Slovakia) was carried out. The karst valley is characterised by climatic and vegetation inversion. To assess the effect of mesoclimate inversion upon soil Collembola five sites were selected in hypsometric sequence from the karst plateau down the valley: (1) subxerophilous pasture – ass. Glechomo–Festucetum, (2) lime wood – ass. Mercuriali–Tilietum, (3) beech wood – ass. Dentario bulbiferae-Fagetum, (4) maple–hornbeam wood – ass. Aceri–Carpinetum, and (5) secondary oak wood. In total 152 soil Collembola species were collected, the numbers for particular sites ranging between 70 and 108. Evidently higher species richness was observed in soil of the beech wood compared to other selected forest plots. Thirteen species revealed affinity to inversed (wet and cold) stands of beech (3) and maple–hornbeam wood (4), four of them represented montane species, whereas five species clearly preferred thermophilous sites (1, 2, 5). The presence of 11 montane species at the bottom of the gorge (4) documented the inverse character of the site: Ceratophysella sigillata, C. silvatica, Friesea albida, Deutonura albella, D. stachi, Superodontella lamellifera, Tetrodontophora bielanensis, Heteraphorura variotuberculata, Kalaphorura carpenteri, Orthonychiurus rectopapillatus and Plutomurus carpaticus. Abundance of Folsomia quadrioculata significantly correlated with the soil microclimate – moisture (p < 0.01, r = 0.92). Distribution data on Collembola were performed by cluster (PC-ORD) and CCA ordination techniques. Collembolan communities of two neighbouring forest stands with identical soil type (rendzina) – lime (2) and beech wood (3) – were the most similar in species composition. Meso-/microclimatic gradients within a karst landscape play an important role in determining diversity and community structure of the soil Collembola.     

Preference of three collembolan species for fruit-bodies of three species of basidiomycete fungi

We examined whether co-existing Hypogastrura species feeding on fruit-bodies show differences in utilization of fruit-bodies, and whether their utilization reflect their preferences for basidiomycete species, by field surveys and bait-trap experiments. In field surveys, the relative densities of the collembolans, Hypogastrura denisana, H. denticulata, and Hypogastrura sp. 1, on the selected basidiomycete species, Cortinarius salor, Lactarius quietus, and Russula emetica, differed significantly between the collembolan species. In bait-trap experiments using fruit-bodies of the three basidiomycete species as bait, the relative densities of the three collembolan species on the basidiomycete species differed significantly between the collembolan species and these differences were similar to the differences observed in the field surveys. These results suggest that the three collembolan species have differential preferences for fruit-bodies of the three selected basidiomycete species, and that the preferences relate to their utilization of fruit-bodies.     

Relationships among species of Hystrix Moench and Elymus L. assessed by RAPDs

To assess the generic delimitation and the interspecific relationships between Hystrix and Elymus, three Hystrix and 10 Elymus species were used for random amplified polymorphic DNA(RAPD) assay. Of the 54 primers tested, 26 (48%) produced polymorphic products. A total of 167 products amplified from 16 primers were selected for RAPD analysis, among which 156 (93.4%) amplified products were found to be polymorphic among the 13 species. The polymorphism produced by each primer ranged from 4 to 13, with an average of 9.8. Data were used to generate Jaccard's similarity coefficients and to construct a dendrogram using UPGMA in the NTSYS computer programs. It is concluded from this study that: (1) there were clear differences between Hystrix and Elymus, which possibly suggest that Hystrix is a valid genus; (2) great diversity existed among the species of Hystrix and Elymus; (3) the species similar to each other in morphological characters were grouped together; (4) the species from neighboring geographical regions were clustered; (5) the species with the same genomes and polyploidy level were clustered together; (6) RAPD results are comparable with those obtained from studies on morphology and cytology. It is a useful additional method for assessing the relationships among genera and species in Triticeae.     

Molecular phylogeny of genus <Emphasis Type="Italic">Guizotia</Emphasis> (Asteraceae) using DNA sequences derived from ITS

Complete sequences for the internal transcribed spacers of the 18s–26s nuclear ribosomal DNA were generated to establish phylogenetic relationships among five species of the genus Guizotia. Parsimony analysis and pairwise distance data produced a single tree with four clearly distinguished clades that accord with previously reported chromosomal data. The clades produced here have been discussed with reference to existing taxonomic treatments. It appears that Guizotia scabra ssp. scabra, G. scabra ssp. schimperi and Guizotia villosa have contributed to the origin of Guizotia abyssinica, the cultivated species of the genus. The present composition of the species of genus Guizotia and the subtribe the genus presently placed in are suggested to be redefined.     

Population diversity of the Vicia sativa agg. (Fabaceae) in the flora of the former USSR deduced from RAPD and seed protein analyses

The genetic diversity of 58 wild and weedy populations representing taxa within the V. sativa aggregate from the former USSR, 4 cultivars of V. sativa, 2 accessions of V. cordata and 3 accessions of V. macrocarpa from Mediterranean countries were analysed using randomly amplified DNA fragments (RAPDs) and seed protein electrophoresis (SDS-PAGE). Interspecific variation between taxa in the V. sativa aggregate could readily be detected using both techniques. RAPDs and seed protein patterns were found to be an effective means of identifying accessions that cannot be identified clearly by morphological criteria alone. RAPD and seed protein analysis revealed a clear relationship between observed genetic variation of populations and their geographical distribution. Populations from each region had their own gene pools. Geographical variation was detected in V. segetalis. The degree of genetic divergence between local populations was usually related to proximity. In several locations where wild and weedy populations of different V. sativa agg. taxa grow sympatrically, intermediate forms could be detected at the DNA and protein levels. Both RAPD and seed protein analysis support the view that the V. sativa aggregate consists of 8 taxa warranting recognition at the species level. Several species in this aggregate are evolving intra-specific groups which can readily be detected at the molecular level.     

Comparative performance of exotic and indigenous forest species for tropical semievergreen degraded forest land reforestation in Chittagong,Bangladesh

Exotic Acacia arabica, Acacia Auriculiformis, Eucalyptus camaldulensis, and Pinus caribaea, and indigenous Albizia lebbek, Cassia siamea, Chikrassia Tabularis, and Derris robusta were reforested in tropical semievergreen degraded forest lands to evaluate their capability of survival, growth, and biomass production in energy plantations. Three years after reforestation, significant variations in growth and biomass yield production were observed within each category of forest species. Both exotic and indigenous forest species had shown similar capability in the biomass production. Plant height was found a better predictor of biomass production than diameter at breast height. There have been improvements in soil properties under reforestation. Among the forest species, indigenous Cassia siamea and Derris robusta, and exotic Acacia auriculiformis were found highly adaptable, fast-growing, productive, and site improving, suitable for reforestation of degraded lands. Copyright © 1999 John Wiley & Sons, Ltd.