Genetic relationships and diversity among Brazilian cultivars and landraces of common beans (Phaseolus vulgaris L.) revealed by AFLP markers

The genetic variation and relationships among 31 accessions of Phaseolus vulgaris L., and two representatives of Vigna unguiculata L., were evaluated by AFLP analysis. A total of 263 DNA fragments across all materials were scored using nine primer combinations, averaging 32 per primer. More than 95% of the amplification products showed polymorphism, indicating high variation at the DNA level among these accessions. Pair-wise genetic similarity (Jaccard's coefficient) ranged from 0.553 to 0.840, with a mean of 0.765. Twenty-three accessions (70%) clustered into three groups. A majority of the commercial cultivars (91%) clustered within a single group, whereas the landraces were distributed along all the variation. An apparent correlation with phaseolin types was detected. Results of this study suggest that Brazilian landraces truly represent the overall genetic variability of Phaseolus vulgaris, confirming the multiple origins of these materials, and their potential as a source of variation for breeding programs.     

Genetic Relationship and Diversity of Four MangiferaSpecies Revealed through AFLP Analysis

We used AFLP analysis to explore the genetic relationship and diversity between and within 4 Mangifera species. We analyzed 35 accessions comprising 8 cultivars and 3 landraces of M. indica L., 11 landraces of M. odorata Griff., 7 landraces of M. foetida Lour., and 6 landraces of M. caesia Jack. Using 8 primer combinations produced a total of 518 bands, 499 (96.3%) of which were polymorphic among the 35 accessions. Clustering analysis showed that all 35 accessions were basically classified into 4 groups corresponding to the 4 Mangifera species. Our results indicate that the genetic relationship of these 4 Mangifera species based on AFLP analysis is in good agreement with their classification by classic methods. In addition, it was clearly revealed the genetic diversity between and within 4 Mangifera species. The findings obtained in this study are useful for the breeding in Mangifera species.     

Molecular Characterization by AFLPs of Capsicum Germplasm from the Amazon Department in Colombia

Using AFLPs, 71 peppers (Capsicum) accessions from the species C. chinense Jacq., C. baccatum L., C. annuum L. and C. frutescens L. from indigenous communities of the Amazon Department (Colombia) were studied to assess the genetic diversity of the collections, and delineate species gene groups. Ten additional accessions were included as a reference species group. Three clusters were identified in the Amazonian accessions by Multiple Correspondence Analyses (MCA) and a dendrogram from the UPGMA analyses of Nei – Li genetic similarity. The clusters correspond to gene groups of the species Capsicum chinense (the majority of the accessions), C. baccatum and the complex annuum - frutescens. A fourth cluster corresponds to the reference accession C. pubescens. The MCA analyses accounted for 95% of the total variation. The total genetic variation was low (Ht 0.119) and a genetic diversity index (Gst) of 0.331 was obtained. This suggests a limited genetic diversity of the accessions and a close relatedness of the species. This study is the first molecular marker assessment of genetic diversity for peppers from the Colombian Amazon, and provides information of biodiversity that can be employed in the preservation and use of Capsicum germplasm.     

Study of clonally propagated cassumunar ginger (<Emphasis Type="Italic">Zingiber montanum</Emphasis> (Koenig) Link ex Dietr.) and its relation of wild <Emphasis Type="Italic">Zingiber</Emphasis> species from Thailand revealed by RAPD markers

The genetic relatedness among 51 accessions, 14 species of the genus Zingiber and genetic variability of a clonally propagated species, Zingiber montanum (Koenig) Link ex Dietr., from Thailand were studied using random amplified polymorphic DNA (RAPD) profiles. Twenty-nine random primers gave reproducible amplification banding patterns of 607 polymorphic bands out of 611 scored bands accounting for 99.40% polymorphism across the genotypes. Jaccard’s coefficient of similarity varied from 0.119 to 0.970, indicative of distant genetic relatedness among the genotype studied. UPGMA clustering indicated eight distinct clusters of Zingiber, with a high cophenetic correlation (r = 1.00) value. Genetic variability in Z. montanum was exhibited by the collections from six regions of Thailand. High molecular variance (87%) within collection regions of Z. montanum accessions was displayed by AMOVA and also explained the significant divergence among the sample from six collection regions. Our results indicate that RAPD technique is useful for detecting the genetic relatedness within and among species of Zingiber and that high diversity exists in the clonally propagated species, Z. montanum.     

Intra-specific DNA polymorphism in pineapple (<Emphasis Type="Italic">Ananas comosus</Emphasis> (L.) Merr.) assessed by AFLP markers

Pineapple (Ananas comosus (L.) Merr.) cultivars, often derived from somatic mutations, are propagated vegetatively. It has been suggested by isozyme data that there is little genetic variation among Smooth Cayenne cultivars. A thorough investigation of the genetic variation within the cultivated speciesAnanas comosus, particularly among commercial cultivars, will provide critical information needed for crop improvement and cultivar protection. One-hundred and forty-eight accessions ofA. comosus and 14 accessions of related species were evaluated with AFLP markers. The average genetic similarity ofA. comosus was 0.735 ranging from 0.549 to 0.972, suggesting a high degree of genetic variation within this species. With AFLP markers, discrete DNA fingerprints were detected for each commercial cultivar, breeding line, and intra-specific hybrid. Self-incompatibility, high levels of somatic mutation, and intraspecific hybridization may account for this high degree of variation. However, major cultivar groups of pineapple, such as Cayenne, Spanish, and Queen, could not be distinctively separated. These cultivar groups are based on morphological similarity, and the similar appearance can be caused by a few mutations that occurred on different genetic background. Our results suggest that there is abundant genetic variation within existing pineapple germplasm for selection, and discrete DNA fingerprinting patterns for commercial cultivars can be detected for cultivar protection. The genetic diversity and relationships of fourAnanas species are also discussed.     

Genetic variation in common and runner bean of the Northern Meseta in Spain

The genetic variation within and between Spanish landraces or varieties of Phaseolus vulgaris L. (common bean) and P. coccineus L. (runner bean) has been estimated by means of isozymes and random amplified polymorphic DNA (RAPD) analyses. Likewise, storage protein and amino acid content in dry seeds have been estimated. Fifteen landraces (60 accessions) of P. vulgaris and six of P. coccineus (six accessions) have been studied. Of the seven isozymatic systems analyzed only three systems and three loci showed variability in each species. Isozyme analyses revealed that genetic variability within and between landraces exist in both species. Even variability within accession was detected in some P. vulgaris landraces. Comparison of isozyme data indicated that Spanish landraces have a lower level of genetic variability than wild American materials and probably also lower than American landraces. RAPD analysis allowed for the uniquely distinguishing of all landraces. Genetic similarity among landraces, estimated by both isozymes and RAPDs, were not related with the seed morphological characters (color, size and shape) which define each variety or landrace. Variation in protein and amino acid content among landraces was also detected. The average protein content in common bean (20.48%) was similar to values previously reported in this species and higher than the average in the runner bean landraces (16.33%). In relation to the amino acid content methionine and cysteine showed the lowest values in all samples, although the content of these two amino acids varied widely among landraces.     

Analysis of genetic diversity in a sweet potato (Ipomoea batatas L.) germplasm collection from Tanzania as revealed by AFLP

Sweet potato (Ipomoea batatas L.) is the fifth most important crop in the developing countries after rice, wheat, maize and cassava. The amplified fragment length polymorphism (AFLP) method was used to study the genetic diversity and relationships of sweet potato accessions in the germplasm collection of Sokoine University of Agriculture, Morogoro and Sugarcane Research Institute, Kibaha, Tanzania. AFLP analysis of 97 sweet potato accessions using ten primer combinations gave a total of 202 clear polymorphic bands. Each one of the 97 sweet potato accessions could be distinguished based on these primer combinations. Estimates of genetic similarities were obtained by the Dice coefficient, and a final dendrogram was constructed with the un-weight pair-group method using arithmetic average. AFLP-based genetic similarity varied from 0.388 to 0.941, with a mean of 0.709. Cluster analysis using genetic similarity divided the accessions into two main groups suggesting that there are genetic relationships among the accessions. Principal Coordinate analysis confirmed the pattern of the cluster analysis. Analysis of molecular variance revealed greater variation within regions (96.19%) than among regions (3.81%). The results from the AFLP analysis revealed a relatively low genetic diversity among the germplasm accessions and the genetic distances between regions were low. A maximally diverse subset of 13 accessions capturing 97% of the molecular markers diversity was identified. We were able to detect duplicates accessions in the germplasm collection using the highly polymorphic markers obtained by AFLP, which were found to be an efficient tool to characterize the genetic diversity and relationships of sweet potato accessions in the germplasm collection in Tanzania.     

Genetic diversity within a range of cultivars and landraces of flax (Linum usitatissimum L.) as revealed by RAPDs

Analysis of the extent and distribution of genetic diversity incrop plants is essential for optimizing sampling and breedingstrategies. We used random amplified polymorphic DNA (RAPD)markers to assess genetic diversity and relationships in 22 Canadiancultivars, 29 selected world cultivars and 10 landraces of flax(Linum usitatissimum L.). RAPDvariation was generally low and more variation was detected among,than within, the investigated flax accessions. Based on 53 variableRAPD loci observed for the 61 accessions, the landraces had a lowerproportion of fixed recessive RAPD loci (0.427) (i.e.,more genetic variation) than all of the flax cultivars examined(0.492). The linseed cultivars had a lower proportion ofrecessive loci (0.469) than the fiber flax cultivars(0.529). Canadian linseed cultivars had a lower proportionof recessive loci (0.465) than the selected world flaxcultivars (0.512). A trend was also observed that the rateof loss in genetic variation in Canadian flax breeding programs overthe last fifty years was approximately two variable loci per 100 lociper 10 years. Clustering analyses based on similarity estimatesshowed that the fiber cultivars were more related (or similar toeach other) and were classified as a homogeneous group. All ofthe linseed cultivars were clustered in diverse groups with the ninelandrace accessions. Implications of these findings for flax breedingand germplasm management are discussed.     

Genetic variability in Macadamia

A genetic variability analysis involving 45 accessions of Macadamia including four species, M. integrifolia, M. tetraphylla, M. ternifolia, and M. hildebrandii and a wild relative, Hicksbeachia pinnatifolia was performed using eight enzyme systems encoded by 16 loci (Gpi-1 and 2, Idh-1 and 2, Lap, Mdh-1, 2, and 3, 6Pgd-2, Pgm-2 and 3, Tpi-1 and 2, Ugpp-1, 2, and 3). Forty-three accessions possessed distinct isozyme fingerprints indicating a high level of genetic variation. Examination of multivariate relationships among accessions using a cluster analysis resulted in the identification of four clusters, two of which contained one accession each representing H. pinnatifolia and M. hildebrandii. All Hawaiian cultivars were included in two sub-clusters within the largest cluster, which encompassed all the M. integrifolia and three M. ternifolia accessions, suggesting that: (1) the Hawaiian cultivars must have originated from at least two genetically diverse ancestral populations and (2) M. ternifolia may be a conspecific variant of M. integrifolia. Macadamia tetraphylla has diverged marginally from the M. integrifolia and M. ternifolia complex suggesting that these taxa represent a species complex. The different measures of genetic variability such as mean number of alleles per locus, polymorphic index, and observed and expected levels of heterozygosity, indicated significant levels of genetic variation in the Macadamia collection.     

The genetic characterization of Turkish watermelon (<Emphasis Type="Italic">Citrullus lanatus</Emphasis>) accessions using RAPD markers

Genetic diversity of the Turkish watermelon genetic resources was evaluated using different Citrullus species, wild relatives, foreign landraces, open pollinated (OP) and commercial hybrid cultivars by RAPD markers. The germplasm was consisted of 303 accessions collected from various geographical regions. Twenty-two of 35 RAPD primers generated a total of 241 reproducible bands, 146 (60.6%) of which were polymorphic. Based on the RAPD data the genetic similarity coefficients were calculated and the dendrogram was constructed using UPGMA (Unweighted pair-group method with arithmetic average). Cluster analysis of the 303 accessions employing RAPD data resulted in a multi-branched dendrogram indicating that most of the Turkish accessions belonging to var. lanatus of Citrullus lanatus (Thunb.) Matsum et Nakai were grouped together. Accessions of different Citrullus species and Praecitrullus fistulosus (Stocks) Pangalo formed distant clusters from C. lanatus var. lanatus. Among 303 accessions, a subset of 56 accessions was selected representing different groups and a second dendrogram was constructed. The genetic similarity coefficients (GS) within the Turkish accessions were ranged from 0.76 to 1.00 with 0.94 average indicating that they are closely related. Taken together, our results indicated that low genetic variability exist among the watermelon genetic resources collected from Turkey contrary to their remarkable phenotypic diversity.     

Genetic diversity of 38 spinach (<Emphasis Type="Italic">Spinacia oleracea</Emphasis> L.) germplasm accessions and 10 commercial hybrids assessed by TRAP markers

Target region amplification polymorphism (TRAP) markers were used to assess genetic variability among 38 germplasm accessions and 10 commercial hybrids of spinach (Spinacia oleracea L.), an economically important leafy vegetable crop in many countries. Germplasm accessions with different geographic origins and 10 commercial hybrids were examined. For assessing genetic diversity within accessions, DNA was extracted from 12 individual seedlings from six germplasm accessions and two hybrids. A relatively high level of polymorphism was found within accessions based on 59 polymorphic TRAP markers generated from one fixed primer derived from the Arabidopsis-like telomere repeat sequence and two arbitrary primers. For evaluating interaccession variability, DNA was extracted from a bulk of six to 13 seedlings of each accession. Of the 492 fragments amplified by 12 primer combinations, 96 (19.5%) were polymorphic and discriminated the 48 accessions from each other. The average pair-wise genetic similarity coefficient (Dice) was 57.5% with a range from 23.2 to 85.3%. A dendrogram indicated that the genetic relationships among the accessions were not highly associated with the geographic locations in which the germplasms were collected. The seven commercial hybrids were grouped in three separate clusters, suggesting that the phenotype-based breeding activities tended to reduce the genetic variability. This preliminary study demonstrated that TRAP markers are effective for fingerprinting and evaluating genetic variability among spinach germplasms. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Genetic variation among populations of wild safflower, <Emphasis Type="Italic">Carthamus oxyacanthus</Emphasis> analyzed by agro-morphological traits and ISSR markers

Wild species of safflower, Carthamus oxyacanthus Bieb., is highly crossable with cultivated species, C. tinctorius L. and could be directly exploited in broadening safflower gene pool and improving the crop for biotic and abiotic stress environments. In this study, genetic diversity among accessions of C. oxyacanthus and their relationships with cultivated safflower were evaluated using agro-morphological traits and polymorphic inter-simple sequence repeats (ISSR) markers. Significant variation was observed among accessions particularly for seeds per capitulum, seed yield per plant, harvest index and capitula per plant. Cluster analysis based on agro-morphological traits classified the wild accessions in two groups according to their geographical regions, and separated them from the cultivated genotypes. ISSR marker also revealed a high genetic variation among the accessions, and cluster analysis based on this marker divided genotypes into four groups, with cultivated ones in a separate clade. Genetic variation observed among the wild safflower germplasm at the DNA level was higher than the agro-morphological traits, indicating that ISSR is an effective marker system for detecting diversity among safflower genotypes and their genetic relationships. Accessions of C. oxyacanthus with high genetic relationship to cultivated species could be used for interspecific hybridization in breeding programs of safflower.     

Analysis of genetic diversity in Indian taro [Colocasia esculenta (L.) Schott] using random amplified polymorphic DNA (RAPD) markers

Taro [Colocasia esculenta (L.) Schott] germplasm accessions collected from different parts of India were subjected to RAPD (Random Amplified Polymorphic DNA) analysis to assess the genetic diversity prevalent and also to test the genetic basis of morphotypic classification. Thirteen random decamer primers out of the 22 tested were used to analyse 32 taro accessions belonging to 28 morphotypes. Three out of these thirteen primers analysed showed 100 per cent polymorphism. Per cent polymorphism varied from 60 to 100 among the polymorphic primers. High genetic diversity was revealed as the similarity coefficient values ranged from 0.50 to 0.98. No two accessions analysed in the present study showed a similarity coefficient value of one thereby indicating their distinctness and presence of high genetic diversity in Indian taro germplasm. Dendrogram obtained from UPGMA analysis grouped 32 accessions in four clusters and three accessions were placed as outliers. Clustering pattern did not show any strict relationship with geographical distribution, morphotype classification and genotypic diversity. Further, accessions classified, as belonging to the same morphotypic group did not always cluster together. Presence of a very close genepool of the wild, weedy and cultivated forms with extreme levels of phenotypic and genotypic variation is suggested as the reason for high genetic diversity reported. Usefulness of DNA markers such as RAPD in characterising and assessing the genetic diversity in Indian taro germplasm is hereby demonstrated.     

RAPD polymorphisms in Aegilops geniculata Roth (Ae. ovata auct. non L.)

Genetic diversity of eighteen accessions of Ae. geniculata (2n=28; UUMM) was assessed using the random amplified polymorphic DNA (RAPD) technique. We optimized RAPD conditions including the template DNA, the concentration of AmpliTaq DNA polymerase Stoffel fragment, and MgCl₂ concentration for revealing polymorphisms. Thirty-eight decamer oligonucleotides were individually used as primers under optimized conditions. Seventeen of these primers produced polymorphic RAPDs among the 18 accessions of Ae. geniculata. Polymorphisms were recorded by noting presence or absence of an amplification product from the total genomic DNA. Comparisons of unique and shared amplification products of each pair of accessions were used to generate genetic similarity coefficients (GSCs). These GSCs were used to construct a phenogram using an unweighted pair-group method with arithmetical averages (UPGMA). The phenogram shows that RAPD data is useful in the measurement of genetic variation or similarity within a species. It also indicates that we can select eight or nine accessions of the eighteen accessions to maintain at least 80% genetic variability of the Chinese collection of Ae. geniculata. Address for correspondence: Dr X-Y. Zhang, USDA-ARS-FRRL, Utah State University, Logan, UT 84322-6300, who is visiting the USA under an agreement between USDA-ARS and CMA-CAAS on germplasm resources.     

Assessment of genetic diversity and genetic relationships among 29 populations of <Emphasis Type="Italic">Azadirachta indica</Emphasis> A. Juss. using RAPD markers

Randomly amplified polymorphic DNA (RAPD) analysis was employed to assess genetic divergence among 29 neem accessions collected from two agro-ecological regions of India (11 agro-climatic sub-zones), which cover three states, Punjab, Haryana and Rajasthan. Out of 24, 10-mer random primers used for studying genetic divergence, 14 were polymorphic, generating a total of 73 amplification products with an average of 5.21 products per polymorphic primer and estimated gene diversity of 0.49. Genetic relationships among accessions were evaluated by generating a similarity matrix based on Jaccard’s coefficient, ranging from 0.70 to 0.96. The phenetic dendrogram generated by UPGMA analysis grouped accessions into five clusters. RAPD performed within accessions (individual seedlings collected from the same mother plant) showed no variation indicating homogeneous population within accessions. Primers OPA-18, OPC-08 and OPI-03 were found most informative based on their resolving power. The degree of genetic variation detected among the 29 accessions with RAPD analysis suggests that RAPD can be used for studying genetic diversity in neem. The study also demonstrated that neem germplasm collected from northwestern plains of India shows no eco-geographical isolation based on sub-zones because accessions collected from different sub-regions are grouping together in the genetic tree.     

Molecular genetic diversity analysis in emmer wheat (Triticum dicoccon Schrank) from India

Emmer wheat (Triticum dicoccon Schrank) is still largely cultivated in India, and highly appreciated for the preparation of traditional dishes. Moreover, its nutritional characteristics could justify a development of its cultivation. The perspective of genetic improvement however requires a good knowledge of the genetic diversity existing within the eco-geographic group of Indian emmer wheats. A set of 48 emmer wheat accessions from India including 28 from a local collection and 20 Indian accessions obtained from CIMMYT, Mexico, was assessed for genetic variability using 47 microsatellite (SSR) markers, distributed over all the 14 chromosomes. The number of alleles per locus ranged from 2 to 9, with an average of 3.87 alleles per locus. A total of 201 alleles were detected at 52 loci with average polymorphic information content of 0.35 per locus and a mean resolving power of 1. The pair-wise similarity coefficients calculated from binary data matrix based on presence or absence of alleles varied from 0.15 to 0.98, but was greater than 0.5 for most accessions, indicating a high level of similarity. A cluster analysis based on the similarity matrix identified nine distinct accessions and three clusters. All the recently developed commercial varieties were distinctly different from the clusters. Based on the analysis, it appears that Indian emmer wheats are not very diverse. Consequently, there is a need to increase the diversity within the Indian emmer wheat eco-geographic group, by introducing diversity from other eco-geographic groups, or even from other wheat species.     

The use of microsatellite polymorphisms to characterise and compare genetic variability in Avena strigosa and A. barbata

Microsatellite (SSR) polymorphism was assessed across 90 diploid Avena strigosa Schreb. and tetraploid Avena barbata Pott ex Link accessions obtained from the USDA-ARS National Small Grains Collection using 105 genomic SSRs. Eleven polymorphic SSRs that detected 69 different alleles were identified and used to genotype the 90 accessions, which were chosen from a larger set of 385 accessions based on geographical source-diversity and variable reaction responses to five Australian pathotypes of the crown rust pathogen Puccinia coronata Corda f. sp. avenae Eriks. Eight diploid and eight tetraploid clades were identified among the 90 accessions. Diploid accessions displayed the lowest genetic diversity, with all accessions being at least 86 % similar, and included accessions from countries in the Americas such as Canada, USA, Argentina, Uruguay and Brazil, and European accessions from France, Romania and Poland. Although both species formed distinct clusters in the dendrogram, a few instances of diploids showing high similarity with tetraploids and vice versa were observed. An AMOVA analysis revealed 86 % of the total genetic variation to be distributed within the two oat species, while between-species differences accounted for only 14 %. Heterozygosity (H) index values of 0.32 and 0.40 were obtained for diploids and tetraploids respectively. Our study effectively differentiated A. strigosa and A. barbata, and identified 11 SSRs suitable for future characterisation of accessions of the two species.     

Pheno-morphological,agronomic and genetic diversity among natural populations of sulla (<Emphasis Type="Italic">Hedysarum coronarium</Emphasis> L.) collected in Sicily,Italy

Sulla (Hedysarum coronarium L.) is a short-lived perennial forage legume that plays a key role in cereal-based systems in semi-arid Mediterranean regions, particularly in organic production and low-input oriented agriculture. In Sicily, the species is widespread both as a wild and cultivated plant. The present study assessed the phenotypic and genetic variation among natural populations of sulla collected from different environments throughout Sicily and analysed how the patterns of phenotypic diversity varied according to the environmental parameters of each collection site. Two commercial varieties and two Sicilian agro-ecotypes were also included in the study as controls. Principal components analysis (PCA) was performed on the sites using geographic, climatic, and pedological data to assess the differences in types of collection sites. PCA was also performed on the accessions (using pheno-morphological and agronomic data) to establish the importance of different traits in explaining multivariate polymorphisms. The results showed a large degree of genetic diversity (based on ISSR markers) and variability in pheno-morphological and agronomic traits. PCA did not clearly differentiate the accessions according to their habitats of origin, but in some cases accessions from the same habitat had a tendency to group together. The agronomic attributes of several populations were more pronounced than those of the controls. The observed variability may be valuable when selecting for H. coronarium varieties suitable for various uses (e.g., hay production, grazing, soil protection).     

Genetic diversity in populations of the medicinal plant <Emphasis Type="Italic">Leonurus cardiaca</Emphasis> L. revealed by inter-primer binding site (iPBS) markers

Motherwort (Leonurus cardiaca L.) is a medicinal plant indigenous to the Mediterranean regions in Europe and Asia. The objective of this study is to apply inter-primer binding site (iPBS) markers to assess the molecular variation and genetic relationships of 89 genotypes of motherwort to assist the genetic improvement of this species. The genotypes comprised 79 from Iran and 10 collected in Australia and 15 additional accessions of two related species (L. heterophyllus Sweet and L. sibiricus L.) collected in Australia, were also included. PCR of 7 iPBS primers (dominant markers) produced a total of 191 bands ranging from 180 to 4000 bp and the mean PIC for primers ranged from 0.2213 to 0.3206 with a mean value 0.2921. The mean expected heterozygosity (0.134), the mean unbiased expected heterozygosity (0.140) and Shannon’s information index (0.213) indicated a high level of inbreeding among the accessions tested. Ordination and cluster analysis showed that the genetic relationships among all accessions could be separated into three major groups—L. cardiaca, L. heterophyllus and L. sibiricus. However, among the 89 accessions of L. cardiaca, genotypes collected from the same geographic region tended to cluster together thus indicating greater genetic similarity. The Motherwort accessions originating in Iran are highly divergent and possess abundant genetic diversity and clearly provide a basis for selection and breeding. The iPBS PCR-based genome fingerprinting technology used in this study is low-cost and effective in differentiating accessions of motherwort and their related species.     

Genetic variation in wild and cultivated artichoke revealedby RAPD markers

Determination of intraspecific genetic diversity is an important first step for the utilization of genetic resources and canprovide useful information on crop evolution. A living collection of Italian and foreign artichoke varieties and ecotypes is maintained at the Germplasm Institute, Bari, Italy. A total of 32 accessions of cultivated (Cynara cardunculus L. var.scolymus (L.) Fiori), three of wild (Cynara cardunculus var.cardunculus L.) artichoke and two ofcultivated cardoon (Cynara cardunculus var.altilis L.) were analysed in order to studygenetic variation and relationships within the species, using RAPDmarkers. Cultivated accessions were selected according tomorphological variation and geographical distribution available inthe collection. Fifty arbitrary decamer primers were initially tested, 18 ofwhich showed from 3 to 10 unambiguously interpretable fragments. Anintra-accession analysis using 4 varieties and 8 polymorphicprimers revealed that no RAPD variation was detected amongindividuals. Jaccard's similarity index (JSI) was comprisedamong 1 and 0.693 when all accessions were considered, on the otherhand, within the cultivated artichoke, JSI ranged between 1 and0.817. A UPGMA dendrogram based on the similarity matrix showed thatwild artichokes were clearly separated from cultivated accessions.Moreover, within cultivated artichokes, several groups could bedistinguished.