Measurement and classification of genetic diversity in okra (Abelmoschus esculentus)

Eighteen accessions of okra of diverse ecological background were evaluated for genetic variability through the techniques of coefficient of racial likeness (CRL) and principal coordinate analysis (PCO). The variation patterns among the accessions were classified by using the techniques of metroglyph analysis and single-linkage cluster analysis. CRL and PCO produced similar results on the diversity of the accessions but the grouping of the accessions by metroglyph analysis and SLCA produced different results. The usefulness of metroglyph analysis depends on the amount of variation accounted for by the two principal characters on which the two co-ordinate axes are constructed. The techniques are compared.     

Genetic and phenotypic variation of Turkish Okra (<Emphasis Type="Italic">Abelmoschus esculentus</Emphasis> L. Moench) accessions and their possible relationship with American,Indian and African germplasms

Okra is an important vegetable crop that provides a significant portion of vitamins and minerals for populations in several countries. Okra has been cultivated in Turkey for centuries, and was likely introduced by the Arabs from Africa in ancient times. In this study, we aimed to clarify the genetic variation within 35 Turkish okra germplasm, by comparing it against 25 different genotypes from India, Africa, and the United States, using 30 morphological characters and 19 sequence-related amplified polymorphism (SRAP) primer combinations. Fruit, leaf, and stem color were the primary characteristics to distinguish the okra accessions. Those features, among 30 individual phenotypic traits, explained 42 % of phenotypic variation in the first three axes of the principal component analysis (PCA) with leaf shape, flower size, cotyledon length, fruit-surface angularity, cotyledon width, and petal color. Phenotypic observation results showed that while 1051 Togo (10.76), Red Wonder (7.99), TR-05-1 (7.2), 1159 Togo (7.17), and Red Balady (7.15) were found to be more divergent accessions, Cajun Queen (5.06), Perkins Spineless (5.09), Jade (5.18), TR-01-1 (5.2), and DLGG (5.32) were the closest okra accessions. According to phenotypic data, Turkish okra accessions were located adjacent to the Indian, American, and African okra accessions in clusters three and four. However, marker data showed that African okra possessed a more distinct form compared to the other okra germplasms. Nineteen SRAP primer combinations produced 92 bands and 29 (31.5 %) of them were found to be polymorphic among okra accessions. 1051 Togo was found to be the most divergent accession in phenotypic observation.     

A Second Edible Okra Species, and its Hybrids with Common Okra

Seventeen accessions of a West African okra species were observedin Puerto Rico, and were hybridized with the common okra species,Abelmoschus esculentus. The accessions are larger plants thancommon okra, but with shorter internodes. They also differ innumerous morphological and physiological characteristics. Mostare more daylength sensitive than common okra. The F₁ hybridsof the two species are quite sterile, although in some casesa few germinable F₂ seeds are produced. Back-crosses, on theother hand, are more fertile than the F₁ hybrids, and fertilityis almost complete in the BC₂. Some evidence was found of cytoplasmicinteraction with chromosomes in production of sterile BC hybrids,a possibly useful tool for future use. Meanwhile, the transferof genes from the new species to common okra appears very feasible. Abelmoschus species, okra, species hybrid, hybrid-sterility     

Assessment of genetic diversity among okra genotypes using SSR markers

Okra (Abelmoschus esculentus) is an important nutritious vegetable. Despite its high economic and industrial value, very little attention has been paid to assess genetic diversity of okra at molecular level. For effective conservation and proper deployment of germplasm, a study on diversity analysis of okra germplasm was conducted with DNA markers. Microsatellite/Simple sequence repeat (SSR) markers were utilized to evaluate the genetic diversity among 96 accessions of Abelmoschus, of which 92 accessions were of A. esculentus and one accession each of A. tuberculatus, A. moschatus, A. moschatus subspecies tuberosus and A. manihot. A set of 40 SSR primers were tested, of which 30 primers gave reproducible amplification which were used further for diversity analysis. With a mean of 7.1 bands per SSR, DNA amplification with 30 SSRs generated a total 213 bands, of which 60.66 % were recorded polymorphic. Polymorphic information content ranged between 0.11 and 0.80 with an average of 0.52, indicating that the majority of primers were informative. The Jaccard’s coefficient ranged from 0.107 to 0.969. The UPGMA analysis grouped Abelmoschus genotypes into three main clusters at a cut-off of 0.20. Results of present study revealed that sufficient variation exists among the studied accessions and GAO-5 which was found highly diverse can be exploited for okra improvement. The outcome of present research would assist to make use of Ablemoschus germplasm for okra breeding.     

Classification of genetic diversity in Abelmoschus tuberculatus germplasm collection using morphometric data

Abelmoschus tuberculatus Pal & Singh is endemic to India and is the close relative of cultivated okra, A. esculentus. Data on 49 selected accessions of A. tuberculatus were used to study genetic diversity for a range of morphological characters through the use of multi-variate statistics. Epicalyx segments, shape, size and persistence; petal colour and petal blotch; stem and fruit pubescence; pigmentation of various plant parts; days to flowering; plant height; and the fruit yield/plant were the important components of variation and contributed significantly to the total variation in germplasm accessions under study. The accessions could be grouped into four distinct clusters. The grouping pattern, however, did not reflect relationship between geographic origin and genetic diversity. The potential use of the variability in okra improvement programmes is discussed.     

Diversity and Species Relationship in Pearl Millet (Pennisetum typhoides) and Related Species

Thirteen accessions of pearl millet (Pennisetum typhoides (L) Leeke) collected from different states of India and eight wild species of the genus Pennisetum across the world were analyzed for genetic diversity using AFLP markers. A combined analysis of eight primer combinations showed 35% polymorphism among P. typhoides accessions while analysis with five primer combinations showed 99% polymorphism among the wild species. The dendrogram constructed for the P. typhoides accessions based on the UPGMA method revealed two major clusters with samples from Gujarat forming a separate cluster from the rest of the samples. Principal component analysis of the same data set revealed similar results with the first principal component accounting for 65% of the total variation. The percentage of rare and common alleles contributing to the diversity in the sample was analyzed using the Shannon Weiner diversity index. The SW index revealed that the samples from Gujarat contributed significantly to the overall diversity among the accessions. Among accessions of each geographical region, considerable variation was revealed by SW index with samples from Tamil Nadu being most polymorphic. The genetic diversity in the accessions could be utilized for future breeding work. The dendrogram constructed for the wild species revealed the extent of genetic diversity among them. Analysis with one primer combination showed P. typhoides being closer to P. mollissimum than to the other analyzed species.     

Genetic Relatedness among Lansium domesticum Accessions Using RAPD Markers

Genetic relatedness among 85 Lansium domesticum Corr. accessionsfrom Peninsular Malaysia were investigated using random amplifiedpolymorphic DNA (RAPD) markers. Ten primers were used for amplificationand yielded a total of 113 bands, of which 107 were polymorphic.Homology tests showed that the RAPD bands used in the studysatisfy assumptions of homology and non-allelic behaviour. Adendrogram showing genetic similarities among accessions wasconstructed based on the 107 polymorphic bands using UPGMA clusteranalysis. Jaccard similarity coefficients ranged from 0.25 to1.00 among accessions indicating a diverse genepool in the speciesindicative of different species parentage. The dendrogram separatedthe 85 accessions into three main clusters, one comprising 56accessions which possess thin-skinned fruit (mostly Dokong andLangsat), while the second has 28 accessions (mostly Duku-langsat,Duku Terengganu and Duku Johor) with thick fruit skin and thethird comprising only one accession, namely Duku hutan. Thus,RAPD analysis was a useful tool for determining the geneticrelatedness among accessions and identifying different typesof L. domesticum. Copyright 2000 Annals of Botany Company Lansium domesticum, genetic relatedness, RAPD markers, cluster analysis     

Genetic Variability ofLepidium meyeniiand other AndeanLepidiumSpecies (Brassicaceae) Assessed by Molecular Markers

A phylogenetic survey based on similarity levels was performedfor 29 cultivated accessions of maca (Lepidium meyeniiWalp.)and 27 accessions of wild species ofLepidiumfrom Ecuador, Peruand Bolivia, with RAPD markers. Chromosome counts for each accessionwere also performed. The similarity tree matrix separated intwo main branches: cultivated and wild species. The similaritylevel among cultivated accessions was high (0.952 or higher)indicating a low level of polymorphism. Within the wild species,two main secondary branches could be resolved, of which onewas subdivided into two tertiary branches. Morphological evaluationof the wild species accessions within each main group identifiedthree wild species: (1)L. bipinnatifidum, consisting mostlyof tetraploids and a single octoploid accession; (2)L. kalenbornii,consisting only of tetraploid accessions; and (3)L. chichicara,consisting mostly of octoploid and a few tetraploid accessions.Clustering by principal coordinates analysis supported the resultsobtained by the similarity tree matrix. These results indicatethat none of the three wild species is related enough to beconsidered ancestral to the cultivatedL. meyenii. Three accessionsof intermediate position may be of hybrid origin. None of thewild species was found to be diploid, which suggests that polyploidyhas been an important adaptation to high altitude habitats inthese species.Copyright 1998 Annals of Botany Company Lepidum meyenii, Lepidium peruvianum, maca, DNA markers, phylogeny.     

Geographical patterns of genetic variation in two species of Stylosanthes Sw. using amplified fragment length polymorphism

Understanding the extent and distribution of genetic diversity within a species is essential for the development of effective conservation strategies. The objective of this study was to assess genetic variation using amplified fragment length polymorphisms (AFLP) in two species of the tropical legume genus Stylosanthes Sw. Annual, S. humilis (2n = 20) and perennial, S. viscosa (2n = 20) are found throughout tropical America, and are sympatric for much of their range of distribution. One hundred and eleven accessions, covering a wide geographical range, were selected for AFLP analysis. Binary data matrices derived from DNA banding patterns were analysed using the software programs NTSYS-PC and ARLEQUIN. Several accessions were found to be misidentified. Of the S. humilis accessions, the overall average similarity value was (0.72) slightly higher than the value obtained for S. viscosa (0.67). Cluster analysis and principal coordinate analysis grouped accessions from both species by geographical origin, with a few exceptions. Analysis of molecular variance (AMOVA) in S. humilis revealed 59.4% of the variation among groups formed from the cluster analysis. This was highly significant (P < 0.001). For S. viscosa AMOVA also revealed more variation among than within groups (66.5%). This was also highly significant (P < 0.001). The majority of accessions of both species conserved ex situ are of Brazilian and Venezuelan origin. This study has identified areas in Central America and Mexico for which novel genetic variation may be found and where conservation activities should be focused.     

Genetic diversity and relationships among Canavalia ensiformis (L.) DC. Accessions as revealed by sequence-related amplified polymorphism markers

Canavalia ensiformis is an under-exploited legume that has been used as forage, green manure, and a cover crop. Thus far, studies of the C. ensiformis germplasm have focused on morphological traits, which cannot be used to distinguish all known accessions or to evaluate their genetic diversity precisely. In this study, sequence-related amplified polymorphism (SRAP) markers were used to assess the genetic diversity and relationships among 29 C. ensiformis accessions originating from 16 countries. In total, 274 clear bands were amplified and 144 of them (52.6%) were polymorphic. The polymorphism information content values (PIC) ranged from 0.10 to 0.43, with an average of 0.27. An analysis of molecular variance (AMOVA) revealed that the most significant variation (92.0% of the total) occurred among accessions; the remaining 8.0% was attributed to variation within accessions. A cluster analysis and principal coordinates (PCoA) analysis produced similar results, whereby the 29 C. ensiformis accessions were divided into 5 clusters, each of which was composed of different accessions with different phenotypic traits. This study provides the theoretical basis for future biodiversity studies and breeding programs.     

Effect of Different Seed Storage Conditions on Germination and Isozyme Activity in Some Brassica Species

Sixteen seed accessions of four Brassica species (B. cretica,B. incana, B. montana and B. oleracea) were examined following5-22 years' storage in the germplasm bank. Germinability andisozyme of seeds stored under long-term (-10 °C and 3% moisturecontent) and short-term (5% °C and 8% moisture content)storage conditions were compared. Long-term storage producedno deterioration and the ability to germinate was satisfactorilymaintained over 8-22 years. Short-term storage conditions maintainedgermination ability up to 10-12 years in all accessions of B.cretica and B. montana. However, seed multiplication might beessential every 10 years for some accessions of B. oleraceastored in this way. In the 8 to 9-year-old accessions of B.cretica, B. incana and B. montana, no significant differenceswere detected between conservation systems for germinabilityand frequency of seeds showing isozyme activity for seven enzymesystems (ACO, IDH, MDH, ME, PGI, PGM and 6-PGD). However, significantdifferences were found for the ADH enzyme system. Moreover,in the 5-22-year-old B. oleracea accessions, significant differenceswere found between storage conditions with respect to isozymeactivity for all enzyme systems studied.Copyright 1995, 1999Academic Press Brassica cretica, Brassica incana, Brassica montana, Brassica oleracea, accessions, isozymes, germination, seed storage     

基于表型性状的孔雀草种质遗传多样性分析

为了了解孔雀草种质间的亲缘关系,提高孔雀草种质的利用效率,从18个形态特征对40份孔雀草种质进行了遗传变异分析、主成分分析及聚类分析。结果表明,孔雀草表型多样性丰富,种质间表型性状变异程度高,变异系数(CV值)范围3.92%~46.25%,以花朵数最大,其次是冠幅和株高;Shannon-Weaver多样性指数则以叶片性状及花性状较高,平均2.0以上。国内种质比国外种质多样性更丰富。通过主成分分析,筛选出对总体方差累计贡献率达78.949%的4个主成分,并筛选出综合性状表现良好的种质10份。参试的40份种质在欧氏距离阈值为7.29处可分为两大类,一类植株生长势较强包含2份种质(水星黄色和橙色);其余38份种质为一类,在欧氏距离阈值为6.0处,又以花色差异可进一步划分为2个类群,说明生长势及花色可作为孔雀草种质依据表型性状分类的重要指标。     

ALLOZYME VARIATION IN OLD WORLD RACES OF SORGHUM BICOLOR (POACEAE)

A survey of allozyme variation in cultivated races of sorghum (Sorghum bicolor) was undertaken. Eight plants each of 83 accessions representing the five primary races and five of the intermediate races of sorghum were analyzed for 15 enzyme systems encoded by 27 loci. Low levels of variation were found within accessions, which is typical of self-pollinating species. Little variation was also found among accessions. Compared with other cereals, S. bicolor is depauperate in allozyme variation. We found an average of 1.81 alleles per locus with a mean expected heterozygosity of 0.008 for the accessions and total panmictic heterozygosity of 0.093. Only 9% of the variation present was found within accessions, while 91% was among accessions. Most of the variation present is attributable to differences in geographic origin of the accessions rather than racial differences. Western and eastern Africa have the highest levels of total heterozygosity (0.108 and 0.088, respectively), while southern Africa has the lowest (0.008). Principal component analysis revealed continuous variation among races and geographic regions with the accessions failing to segregate into discrete racial or geographic clusters.     

Revisiting the role of LCA and SLCA in the transition towards sustainable production and consumption

Purpose

Life Cycle Analysis (LCA) and Social Life Cycle Analysis (SLCA) are tools acknowledged to have a role to play in the transition towards Sustainable Production and Consumption patterns (SPC). However, the role they play in this transition is seldom discussed, especially for SLCA. In addition, although the importance of taking a life cycle thinking (LCT) in the progression towards SPC seems indisputable, its added value is seldom made explicit. This article wishes to highlight the role of SLCA in the transition towards more sustainable production and consumption patterns and questions the relevance of LCT in this role.

Methods

To answer this question, we first identify the applications of SLCA that correspond to actions that have to be taken in the transition towards SPC based on the SPC and SLCA literature. Then, the relevance of LCT in the context of the different applications identified previously is questioned through a qualitative discursive analysis approach.

Results

The social goal of SPC is poorly discussed, and the SLCA literature can be one source of inspiration to define what this goal could be. On the basis of the UNEP-SETAC (2009) Guidelines’ SLCA ultimate goal, SPC could be a means to improve stakeholders’ social conditions through the improvement of enterprises’ behaviours. The intended applications of SLCA for potentially supporting the improvement of enterprises’ behaviours are found to be the identification of hotspots in order to highlight areas of improvement inside the sphere of influence of the SLCA user and the guidance of purchasing and substitution choices on the basis of enterprises’ behaviours. In this article, it is suggested that, for SLCA to deserve the “LCT label”, it has to capture impact transfers along the products’ life cycle. Otherwise, an “ability-to-act-on” perspective is the proper angle to adopt in the identification of areas of improvement inside the sphere of influence and a “cradle-to-retailer”, the one to adopt when SLCA is used to guide buy/boycott.

Conclusions

Aside from revisiting the role of LCA and SLCA in SPC and the raison d’être of LCT, we discuss some considerations which we believe should be taken into account when developing SLCA in the context of SPC. In conclusion, this article points to the importance of framing the use of Life Cycle Sustainability Assessment tools in their context of use.     

Isozyme and RAPD Analysis of the Genetic Diversity Within and BetweenVigna luteolaandV. marina

Nineteen accessions ofVigna luteola,five ofV. marinassp.oblonga,and two ofV. marinassp.marinawere analysed using variation ofisozymes and RAPD markers to obtain better insight into geneticrelationships within and between these taxonomic entities. Thirteenputative isozyme loci were scored, seven of which were polymorphic.Both species showed very low genetic diversity indices and mostof the variation was detected among populations. Pairwise Nei'sgenetic distances based on allozyme frequencies were also verylow and the accessions ofV. marinassp.marinawere the least relatedto the others. RAPD analysis was more discriminating and 66bands out of a total of 85 were polymorphic. Based on the presenceor absence of bands, Jaccard's similarity index was calculated.Similarity ranged from 0.476 to 0.98. Matrices derived fromboth isozyme and RAPD data were used to construct UPGMA dendrograms.In the tree obtained from Nei's genetic distance, based on allozymefrequencies, accessions belonging toV. marinassp.oblongaweremixed withV. luteolaaccessions; on the other hand, the twoV.marinassp.marinaclustered separately, with oneV. luteola.Thedendrogram derived from RAPD data showed three main groups correspondingto the three taxa analysed. Moreover, according to these data,V.marinassp.oblongais more closely related toV. luteolathan toV.marinassp.marina.Copyright 1997 Annals of Botany Company Vigna luteola(Jacq.) Benth.; Vigna marina(Burm.) Merrill; isozymes; RAPDs; genetic relationships; genetic variation     

Developmental Responses to Temperature and Photoperiod in Ecotypes of Medicago polymorpha L. Collected Along an Environmental Gradient in Central Chile

The phenological development of nine Chilean accessions of Medicagopolymorpha, collected along a north–south aridity gradient,and of two commercial cultivars of the same species, were comparedin 12 sequential outdoor sowings at Cauquenes (35°58'S,72°17'W, elev. 177 m), in the sub-humid Mediterranean climatezone of Chile. A glasshouse experiment was also conducted toevaluate the effect of photoperiod on phenophase timing. Therewas a clear gradient in precocity among the Chilean accessionsin both experiments: accessions MPO-9-88 and MPO-7-88, fromthe arid zone, were the earliest-flowering accessions, whereasMPO-36-88 from the humid Mediterranean zone was the latest.Both experiments revealed significant variation among the Chileanaccessions in the response of flowering time to variation inphotoperiod regime. Differences in days to flowering betweenthe least- (8 h) and the most- (16 h) inductive photoperiodswere lower in precocious accessions from arid and semi-aridzones, than in late-flowering accessions from more humid zones.Rate of progress to flowering, defined as the inverse of timefrom emergence to first flower appearance (1/ f), was relatedto mean diurnal temperature, or to both mean diurnal temperatureand mean photoperiod. In two early-flowering accessions fromthe arid zone, and in the Australian cultivar ‘CircleValley’, 1/ f was affected significantly (P < 0.05)by both temperature and photoperiod. In the remaining accessions,no significant responses to temperatures were detected; 1/ fwas influenced significantly by photoperiod only. Copyright2000 Annals of Botany Company Annual medic, aridity gradient, Medicago polymorpha, flowering time, rate of development     

Geographic and altitudinal allozyme variation in sorghum (Sorghum bicolor (L.) Moench) landraces from Ethiopia and Eritrea

The amount and distribution of genetic variation was investigated in 48 sorghum landrace accessions, representing 13 regions of origin and three adaptation zones (lowland, intermediate and highland elevation) in Ethiopia and Eritrea. Assaying 11 enzymes systems, 23 putative loci were scored for a total of 27 alleles. Nineteen loci were monomorphic and fixed for the same allele, while the remaining 4 loci, each with 2 alleles, were polymorphic across the 48 accessions. The results show significant differences in allele frequencies among the accessions, regions of origin and the adaptation zones. However, all measures of genetic variation used show that the accessions maintained much lower levels of variation than the corresponding mean values for self-pollinating crop plants, confirming previous conclusions that sorghum is depauperated in allozymic variation. The total gene diversity was 0.25, which partitioned 59% within and 41% among accessions. The latter was largely due to variation among accessions within the adaptation zones (38%), while only 3% was due to variation among accessions between the adaptation zones. Similarly, most of the total gene diversity was found within the regions of origin (80%) and within the adaptation zones (97%). Both the dendrogram constructed from NEI's unbiased genetic distance and the plot of the first two principal components distinguished three groups of regions. The level of gene flow was low among accessions, regions of origin and among accessions within adaptation zones, but high among adaptation zones. The results are discussed with emphasis on genetic resources conservation and utilization.