Mapping of AFLP markers linked to seed coat colour loci in<Emphasis Type="Italic"> Brassica juncea</Emphasis> (L.) Czern

Association mapping of the seed-coat colour with amplified fragment length polymorphism (AFLP) markers was carried out in 39 Brassica juncea lines. The lines had genetically diverse parentages and varied for seed-coat colour and other morphological characters. Eleven AFLP primer combinations were used to screen the 39 B. juncea lines, and a total of 335 polymorphic bands were detected. The bands were analysed for association with seed-coat colour using multiple regression analysis. This analysis revealed 15 markers associated with seed-coat colour, obtained with eight AFLP primer combinations. The marker E-ACA/M-CTG₃₅₀ explained 69% of the variation in seed-coat colour. This marker along with markers E-AAC/M-CTC₂₃₅ and E-AAC/M-CTA₂₅₀ explained 89% of the total variation. The 15 associated markers were validated for linkage with the seed-coat colour loci using a recombinant inbred line (RIL) mapping population. Bands were amplified with the eight AFLP primer combinations in 54 RIL progenies. Of the 15 associated markers, 11 mapped on two linkage groups. Eight markers were placed on linkage group 1 at a marker density of 6.0 cM, while the remaining three were mapped on linkage group 2 at a marker density of 3.6 cM. Marker E-ACA/M-CTG₃₅₀ co-segregated with Gene1 controlling seed-coat colour; it was specific for yellow seed-coat colour and mapped to linkage group 1. Marker E-AAC/M-CTC₂₃₅ (AFLP8), which had been studied previously, was present on linkage group 2; it was specific for brown seed-coat colour. Since AFLP markers are not adapted for large-scale applications in plant breeding, it is important to convert these to sequence-characterised amplified region (SCAR) markers. Marker E-AAC/M-CTC₂₃₅ (AFLP8) had been previously converted into a SCAR. Work is in progress to convert the second of the linked markers, E-ACA/M-CTG₃₅₀, to a SCAR. The two linked AFLP markers converted to SCARs will be useful for developing yellow-seeded B. juncea lines by means of marker-assisted selection.Communicated by H.F. Linskens     

Characterisation of Chinese elite cultivars and genetic resources of chestnut by AFLP

We selected a informative set of twelve amplified fragment length polymorphism (AFLP) primer pairs suitable for evaluation of Chinese chestnut (Castanea mollissima Blume) genotypes. Cluster analysis based on 198 polymorphic AFLP amplified by these 12 primer pairs clearly divided investigated genotypes according to their place of origin. We showed, that genetic basis of modern genotypes is narrow also in the case of this species.     

Development of AFLP and STS markers linked to a waterlogging tolerance in Korean soybean landraces

Among the 400 soybean (Glycine max) landraces, we selected 3 tolerant (KAS150-9, KAS160-15, and KAS170-9) and 3 susceptible lines (KAS160-14, KAS160-20, and KAS201-6-1) by the survival percentage and injury scores. Susceptible lines showed decrease in chlorophyll content and increase in glucose and malondialdehyde (MDA) contents under waterlogging stress, while tolerant lines did not change significantly. For AFLP analysis, 8 EcoRI (+3) and 8 MseI (+3) primers used in 32 primer combinations generated a total of 2 566 bands with a mean of 80 bands per primer combination, of which 1 117 (43.5 %) were clearly polymorphic between the tolerant and susceptible lines. A genetic similarity coefficient, based on cluster analysis using an unweighted pair grouping method of average (UPGMA), was 0.79 for the tolerant group, while the susceptible landraces were genetically less related, with a genetic similarity coefficient of 0.17. The 10 reproducible polymorphic PCR products present in the 3 tolerant or susceptible lines were sequenced and converted into sequence tagged site (STS) markers. These STS primer sets were designated GmWT01-GmWT06 and GmWS01-GmWS04. Two STS primer sets, GmWT06 and GmWS02, generated a single monomorphic PCR product identical in size to the original AFLP fragments. For the broad application of these STS markers in marker-assisted selection (MAS) for soybean genotypes tolerant to waterlogging stress, two developed STS markers are being evaluated with putative waterlogging tolerant mutant lines induced by γ-radiation in soybean mutation breeding programs.     

Establishment of AFLP technique and assessment of primer combinations for mei flower

Mei flower is one of the most famous ornamental flowers in eastern Asia for its blossoming in early spring. Amplified fragment length polymorphism (AFLP) is one of the most frequently used techniques for analysis of genetic variation and is used herein for the first time inPrunus mume. This research provides a detailed and modified AFLP protocol for Mei genomic DNA digested withEcoRI/PstI restriction endonuclease combinations. The 10 best primer pairs of high polymorphism were screened from 256 primer combinations that could reliably and repetitively distinguish 14 Mei samples and would be suitable for genetic analysis of more cultivars. Ten primer pairs produced up to a total of 524 AFLP bands and up to 233 polymorphic bands. The ratio of polymorphic bands scoped from 35.71% to 59.67%, and the average ratio was 44.46% in the 10 primers. AFLP is an effective, inexpensive, and timesaving technique for the genetic differentiation of the Mei cultivars, as evidenced in this study.     

Identification of molecular markers in soybean comparing RFLP,RAPD and AFLP DNA mapping techniques

Three different DNA mapping techniques—RFLP, RAPD and AFLP—were used on identical soybean germplasm to compare their ability to identify markers in the development of a genetic linkage map. Polymorphisms present in fourteen different soybean cultivars were demonstrated using all three techniques. AFLP, a novel PCR-based technique, was able to identify multiple polymorphic bands in a denaturing gel using 60 of 64 primer pairs tested. AFLP relies on primers designed in part on sequences for endonuclease restriction sites and on three selective nucleotides. The 60 diagnostic primer pairs tested for AFLP analysis each distinguished on average six polymorphic bands. Using specific primers designed for soybean fromEco RI andMse I restriction site sequences and three selective nucleotides, as many as 12 polymorphic bands per primer could be obtained with AFLP techniques. Only 35% of the RAPD reactions identified a polymorphic band using the same soybean cultivars, and in those positive reactions, typically only one or two polymorphic bands per gel were found. Identification of polymorphic bands using RFLP techniques was the most cumbersome, because Southern blotting and probe hybridization were required. Over 50% of the soybean RFLP probes examined failed to distinguish even a single polymorphic band, and the RFLP probes that did distinguish polymorphic bands seldom identified more than one polymorphic band. We conclude that, among the three techniques tested, AFLP is the most useful.     

冬枣×宁梨巨枣的子代SRAP鉴定及遗传多样性分析

应用SRAP分子标记方法对冬枣×宁梨巨枣的子代进行了分子鉴定及遗传多样性分析。采用构建基因池的方法对SRAP分子标记引物进行筛选,从88对引物中筛选出15对多态性好、主带清晰的引物,并对子代进行了真实性鉴定及多态性分析。结果表明:(1)15对引物共产生95个多态性条带,平均每对引物产生6.3个多态性条带,显示了较高的多态性比率。(2)80个子代中44个具有父本特征带,鉴定为真杂种。子代遗传多样性及UPGMA聚类分析表明,子代个体与亲本间的遗传相似系数在0.55~0.98之间,个体差异明显。该研究结果为枣树杂交育种提供了重要的分子证据。     

AFLP analysis of genetic relationships among aromatic grapevines (<Emphasis Type="Italic">Vitis vinifera</Emphasis>)

Genotypic diversity has been detected among aromatic grapevines (Vitis vinifera) by molecular markers (AFLPs). The 22 primer-pairs generated a total of 1,331 bands of which 564 (40%) were polymorphic over all the genotypes. The bootstrap analysis pointed out that a large number of polymorphic bands (200–400) has to be used for a better estimation of the genetic distances among genotypes; 383 polymorphic AFLP bands were used for the cluster and the principal coordinate analyses because they did not present missing data across all the genotypes. The cluster analysis (UPGMA), based on polymorphic AFLP markers, revealed no relationship between the Moscato and Malvasia grapevines. The Malvasias, unlike the Moscatos distinguished by their distinct muscat aroma, have to be considered a more complex group because it includes muscat and non-muscat grapevines. The principal coordinate analysis (PCO) confirmed the pattern of the cluster analysis only for those varieties which presented a low coefficient of dissimilarity, while for the other varieties there was no correspondence between the two analyses. The pattern of aggregation among aromatic grapevines in the cluster and principal coordinate analyses does not support any classification that might include an aromatic grapevine group in V. vinifera. Even though some synonyms and homonyms are present among aromatic grapevines (V. vinifera), genetic diversity exists among genotypes in AFLP markers.Communicated by H.F. Linskens     

Identification of AFLP fragments linked to seed coat colour in Brassica juncea and conversion to a SCAR marker for rapid selection

A Brassica juncea mapping population was generated and scored for seed coat colour. A combination of bulked segregant analysis and AFLP methodology was employed to identify markers linked to seed coat colour in B. juncea. AFLP analysis using 16 primer combinations revealed seven AFLP markers polymorphic between the parents and the bulks. Individual plants from the segregating population were analysed, and three AFLP markers were identified as being tightly linked to the seed coat colour trait and specific for brown-seeded individuals. Since AFLP markers are not adapted for large-scale application in plant breeding, our objective was to develop a fast, cheap and reliable PCR-based assay. Towards this goal, we employed PCR-walking technology to isolate sequences adjacent to the linked AFLP marker. Based on the sequence information of the cloned flanking sequence of marker AFLP8, primers were designed. Amplification using the locus-specific primers generated bands at 0.5 kb and 1.2 kb with the yellow-seeded parent and a 1.1-kb band with the brown-seeded parent. Thus, the dominant AFLP marker (AFLP8) was converted into a simple codominant SCAR (Sequence Characterized Amplified Region) marker and designated as SCM08. Scoring of this marker in a segregating population easily distinguished yellow- and brown-seeded B. juncea and also differentiated between homozygous (BB) and heterozygous (Bb) brown-seeded individuals. Thus, this marker will be useful for the development of yellow seed B. juncea cultivars and facilitate the map-based cloning of genes responsible for seed coat colour trait. Received: 2 October 1999 / Accepted: 11 November 1999     

Differentiation of bermudagrass (Cynodon spp.) genotypes by AFLP analyses

 Bermudagrasses (Cynodon spp.) are major turfgrasses for home lawns, public parks, golf courses and sport fields, and are widely adapted to tropical and warmer temperate climates. Morphological and physiological characteristics are not sufficient to differentiate some bermudagrass genotypes because the differences between them are often subtle and subject to environmental influence. In this study, a DNA-typing technique, amplified fragment length polymorphism (AFLP), was used to differentiate bermudagrass genotypes and to explore their genetic relationships. Twenty seven bermudagrass cultivars and introductions, mostly from the Coastal Plain Experiment Station in Tifton, Ga., were assayed by the radioactive (³²P) and the fluorescence-labeled AFLP methods. The AFLP technique produced enough polymorphism to differentiate all 27 bermudagrass genotypes, even the closely related ones. An average of 48–74 bands in the 30–600-bp size range was detected by the ³²P-labeled AFLP method. The results indicated that most of the 14 primer combinations tested in this study could be used to distinguish bermudagrass genotypes, and that some single primer-pairs could differentiate all 27 of them. To test the reliability and reproducibility of the AFLP procedure, three DNA isolations (replications) of the 27 bermudagrass genotypes were assayed using five primer pairs. Only 0.6% of the bands were evaluated differently among the three replications. One replication of one genotype (which was most likely a planting contaminant) was grouped in an unexpected cluster using the Unweighted Pair Group Mean Average (UPGMA) method. A one- or two-band difference in scoring did not change the clustering of genotypes or the replications within genotypes. The 27 genotypes were grouped into three major clusters, many of which were in agreement with known pedigrees. Trees constructed with different primer combinations using ³²P- and fluorescence-labelling formed similar major groupings. The semi-automated fluorescence-based AFLP technique offered significant improvements on fragment sizing and data handling. It was also more accurate for detection and more efficient than the radioactive labelling method. This study shows that the AFLP technique is a reliable tool for differentiating bermudagrass genotypes and for determining genetic relationships among them. Received: 28 July 1998 / Accepted: 3 November 1998     

Changes in AFLP and SSR DNA polymorphisms induced by short-term space flight of rice seeds

Differences of both amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) polymorphisms were compared between the 60-d-old rice (Oryza sativa L. cv. DH7) and F3 rice plants (SP3) derived from seed, which endured a 7-d-space flight in March 2002. Total leaf AFLP DNA bands amplified from 22 primer pairs were 537 in DH7, whereas 562 in SP3. From the total 267 SSR DNA bands generated by 267 primer pairs, 39 were polymorphic with 22 larger (56 %) or 17 smaller (44 %) fragment size bands. The greatest numbers of AFLP DNA bands were amplified by primer E1M1 in DH7 (33) and E3M1 in SP3 (35), whilst the least by E4M3 in DH7 (14) and E5M2 in SP3 (16).     

Identification ofporphyra lines (rhodophyta) by AFLP DNA fingerprinting and molecular markers

Twenty-sevenPorphyra lines from 5 classes, including lines widely used in China, wild lines, and lines introduced to China from abroad in recent years, were screened by means of amplified fragment length polymorphism (AFLP) with 24 primer pairs. From the generated AFLP products, 13 bands that showed stable and repeatable AFLP patterns amplified by primer pairs M-CGA/E-AA and M-CGA/E-TA were scored and used to develop the DNA fingerprints of the 27Porphyra lines. Moreover, the DNA fingerprinting patterns were converted into computer language expressed with digitals 1 and 0, which represented the presence (numbered as 1) or absence (numbered as 0) of the corresponding band. On the basis of these results, computerized AFLP DNA fingerprints were constructed in which each of the 27Porphyra lines has its unique AFLP fingerprinting pattern and can be easily distinguished from others. Software called PGI-AFLP (Porphyra germ-plasm identification-AFLP) was designed for identification of the 27Porphyra lines. In addition, 21 specific AFLP markers from 15Porphyra lines were identified; 6 AFLP markers from 4Porphyra lines were sequenced, and 2 of them were successfully converted into SCAR (sequence characterized amplification region) markers. The developed AFLP DNA fingerprinting and specific molecular markers provide useful ways for the identification, classification, and resource protection of thePorphyra lines.     

Comparative Evaluation of RAPD and AFLP Based Genetic Diversity in Brinjal (Solanum melongena)

The present investigation was carried out with an objective of evaluating genetic diversity in brinjal (Solanum melongena) using DNA markers. A total of 38 brinjal accessions including one wild-species, Solanum sisymbrifolium were characterized using random amplified polymorphic DNA (RAP D) and amplified fragment length polymorphism (AFLP) techniques. Out of 45 primers employed to generate RAPD profiles, reproducible patterns were obtained with 32 primers and 30 (93.7%) of these detected polymorphism. A total of 149 bands were obtained, out of which 108 (72.4%) were polymorphic. AFLP analysis was carried out using four primer combinations. Each of these primers was highly polymorphic. Out of 253 fragments amplified from these four primer combinations, 237 (93.6%) were polymorphic. The extent of pair-wise similarity ranged from 0.264 to 0.946 with a mean of 0.787 in RAPD, in contrast to a range of 0.103 to 0.847 with a mean of 0.434 in AFLP. The wild species clustered separately from the brinjal genotypes. In the dendrogram constructed separately using RAPD and AFLP markers, the brinjal genotypes were grouped into clusters and sub-clusters, and the varieties released by IARI remained together on both the dendrograms. All the 30 RAPD primers in combination and each of the four primer pairs in AFLP could distinguish the brinjal accessions from each other. AFLP was thus found to be more efficient than RAPD in estimation of genetic diversity and differentiation of varieties in brinjal.     

Association analysis,genetic diversity and structure analysis of tobacco based on AFLP markers

Knowledge in the area of genetic diversity could aid in providing useful information in the selection of material for breeding such as hybridization programs and quantitative trait loci mapping. To this end, 50 Nicotiana tabacum genotypes were genotyped with 21 primer combination of amplified fragment length polymorphism (AFLP). A total of 480 unambiguous DNA fragments and 373 polymorphic bands were produced with an average of 17.76 per primer combination. Also, the results revealed high polymorphic rate varing from 52.63 to 92.59 %, demonstrating that AFLP technique utilized in this research can be a powerful and valuable tool in the breeding program of N. tabacum. Cluster analysis based on complete linkage method using Jaccard’s genetic distance, grouped the 50 tobacco genotypes into eight clusters including three relatively big clusters, one cluster including Golden gift, Burly 7022 and Burly Kreuzung, one cluster consisting of two individuals (Pereg234, R9) and three single-member clusters (Pennbel69, Coker176 and Budisher Burley E), Recent genotypes showed high genetic distance from other genotypes belonging to cluster I and II. Association analysis between seven important traits and AFLP markers were performed using four statistical models. The results revealed the model containing both the factors, population structure (Q) and general similarity in genetic background arising from shared kinship (K), reduces false positive associations between markers and phenotype. According to the results nine markers were determined that could be considered to be the most interesting candidates for further studies.     

Development of AFLP-derived STS markers for the selection of 5-methyltryptophan-resistant rice mutants

To increase the specific free amino acid content in the japonica rice (Oryza sativa L.) cultivar Donganbyeo, mutant cell lines resistant to growth inhibition by 5-methyltryptophan (5MT) were selected from embryo-cultured callus irradiated with 50 Gy gamma-rays. Four 5MT-resistant homozygous M₄ lines, MRI-40, MRI-116, MRII-8, and MRII-12, were obtained. The mean content of nine free essential amino acids were 70.1, 72.5, 31.7, and 35.4% greater than the original variety in these four mutant lines, respectively. For AFLP analysis, 8 EcoRI (+2) and 8 MseI (+3) primers used in 45 primer combinations generated a total of 3,684 bands with a mean of 82 bands, of which 361 (9.8%) were clearly polymorphic with the control cultivar, the four 5MT-resistant mutants, and five sensitive lines. The lines were grouped into three clusters through cluster analysis using unweighted pair grouping method of averages. The 36 polymorphic PCR products present only in the four homozygous 5MT-resistant lines were cloned and sequenced, and 10 of these sequenced products were converted into sequence tagged site (STS) markers. These STS primer sets were designated OSMR1–OSMR10. Six STS primer sets (OSMR1, OSMR2, OSMR3, OSMR4, OSMR5, and OSMR6) generated a single monomorphic PCR product identical in size to the original AFLP fragments. The broad applicability of these STS markers for the screening of 5MT resistance was evaluated with seven putative 5MT-resistant M₂ plants (PM-1 to PM-7). Four STS markers (OSMR1, OSMR2, OSMR4, and OSMR5) out of six STS primer sets were revealed as polymorphic products between the control cultivar and the seven M₂ plants. These markers can be utilized for the fine selection of 5MT resistance in rice, and this PCR-screening technique is less time-consuming, less labor-intensive, and more accurate and reliable than selection based solely on phenotypic evaluation involving soaking in 5MT solutions.Abbreviations AFLP Amplified fragment length polymorphism - MAS Marker-assisted selection - STS Sequence tagged site - UPGMA Unweighted pair grouping method of averages - 5MT 5-Methyltryptophan     

Cleaved AFLP (cAFLP), a modified amplified fragment length polymorphism analysis for cotton

In certain plant species including cotton (Gossypium hirsutum L. or Gossypium barbadense L.), the level of amplified fragment length polymorphism (AFLP) is relatively low, limiting its utilization in the development of genome-wide linkage maps. We propose the use of frequent restriction enzymes in combination with AFLP to cleave the AFLP fragments, called cleaved AFLP analysis (cAFLP). Using four Upland cotton genotypes (G. hirsutum) and three Pima cotton (G. barbadense), we demonstrated that cAFLP generated 67% and 132% more polymorphic markers than AFLP in Upland and Pima cotton, respectively. This resulted in 15.5 and 25.5 polymorphic cAFLP markers per AFLP primer combination, as compared to 9.1 and 11.0 polymorphic AFLP. The cAFLP-based genetic similarity (GS) is generally lower than the AFLP-based GS, even though both marker systems are overall congruent. In some cases, cAFLP can better resolve genetic relationships between genotypes, rendering a higher discriminatory power. Given the high-resolution power of capillary-based DNA sequencing system, we further propose that AFLP and cAFLP amplicons from the same primer combination can be pooled as one sample before electrophoresis. The combination produced an average of 18.5 and 31.0 polymorphic markers per primer pair in Upland and Pima cotton, respectively. Using several restriction enzyme combinations before pre-selective amplification in combination with various frequent 4 bp-cutters or 6 bp-cutters after selective amplification, the pooled AFLP and cAFLP will provide unlimited number of polymorphic markers for genome-wide mapping and fingerprinting.     

Genetic relatedness and genetic diversity of ornamental mei (Prunus mume Sieb. et Zucc.) as analysed by AFLP markers

The genetic diversity and genetic relatedness of mei (Prunus mume; 2n = 16) were studied using amplified fragment length polymorphism (AFLP) markers. Eight EcoRI–PstI AFLP primer combinations were applied to 121 distinct genotypes of mei cultivars and related species. A total of 508 AFLP product bands were produced, of which 382 were polymorphic. The unweighted pair group method with arithmetic averages analysis was carried out based on these AFLP markers. From this analysis, “Qugeng Mei,” “Yan Mei,” “Chaodou Mei,” and mei cultivars were seen to share the same P. mume genetic stem. The AFLP data were able to clearly discriminate P. mume from other species in the genus Prunus, with P. armeniaca aligning as its closest related species. Two major groups and nine subgroups of mei flower were identified, and there was a strong coincidence of these AFLP-based groupings with the respective morphological characters of the accessions. The genetic diversity of mei accessions was greatest in the Yunnan Province and decreased toward Eastern China and Japan, so supporting the hypothesis that the southwest of China represents the genetic diversity center of the species.     

Genetic Diversity of Pyrenophora teres Isolates as Detected by AFLP Analysis

Amplified fragment length polymorphism (AFLP) analysis has been used to analyse mainly 83 Czech isolates of Pyrenophora teres, P. graminea, P. tritici‐repentis and Helminthosporium sativum. Each species had distinct AFLP profiles. Using 19 primer combinations 948 polymorphic bands were detected. All main clusters in dendrogram correspond to the studied species. Even the two forms of P. teres–P. teres f. teres (PTT) and P. teres f. maculata (PTM) – formed different clusters. Genetic diversity, with regard to the locality and the year of the sample's collection, was analysed separately within the AFLP‐based dendrogram cluster of PTT and PTM. Unweighted pair‐group method (UPGMA) analysis of the 37 isolates of PTT and 30 isolates of PTM, using 469 polymorphic bands, showed that the variability seemed to have been influenced more by the year of sampling than by the geographic origin of the isolate. The presence of intermediate haplotypes with a relatively high number of shared markers between the two groups indicated that hybridization between the forms of P. teres could happen, but it is probably often overlapped by selection pressure or genetic drift.     

Genetic differentiation of <Emphasis Type="Italic">Vigna</Emphasis> species by RAPD,URP and SSR markers

Seventy genotypes belonging to 7 wild and cultivated Vigna species were genetically differentiated using randomly amplified polymorphic DNA (RAPD), universal rice primer (URP) and simple sequence repeat (SSR) markers. We identified RAPD marker, OPG13 which produced a species-specific fingerprint profile. This primer characterized all the Vigna species uniquely suggesting an insight for their co-evolution, domestication and interspecific relationship. The cluster analysis of combined data set of all the markers resulted in five major groups. Most of the genotypes belonging to cultivated species formed a specific group whereas all the wild species formed a separate cluster using unweighted paired group method with arithmetic averages and principle component analysis. The Mantel matrix correspondence test resulted in a high matrix correlation with best fit (r = 0.95) from combined marker data. Comparison of three-marker systems showed that SSR marker was more efficient in detecting genetic variability among all the Vigna species. The narrow genetic base of the V. radiata cultivars obtained in the present study emphasized that large germplasm collection should be used in Vigna improvement programme.     

Amplified fragment length polymorphism (AFLP) in soybean: species diversity, inheritance, and near-isogenic line analysis

Amplified fragment length polymorphism (AFLP) analysis is a PCR-based technique capable of detecting more than 50 independent loci in a single PCR reaction. The objectives of the present study were to: (1) assess the extent of AFLP variation in cultivated (Gycine max L. Merr.) and wild soybean (G. soja Siebold & Zucc.), (2) determine genetic relationships among soybean accessions using AFLP data, and (3) evaluate the usefulness of AFLPs as genetic markers. Fifteen AFLP primer pairs detected a total of 759 AFLP fragments in a sample of 23 accessions of wild and cultivated soybean, with an average of 51 fragments produced per primer pair per accession. Two-hundred and seventy four fragments (36% of the total observed) were polymorphic, among which 127 (17%) were polymorphic in G. max and 237 (31%) were polymorphic in G. soja. F₂ segregation analysis of six AFLP fragments indicated that they segregate as stable Mendelian loci. The number of polymorphic loci detected per AFLP primer pair in a sample of 23 accessions ranged from 9 to 27. The AFLP phenotypic diversity values were greater in wild than in cultivated soybean. Cluster and principal component analyses using AFLP data clearly separated G. max and G. soja accessions. Within the G. max group, adapted soybean cultivars were tightly clustered, illustrating the relatively low genetic diversity present in cultivated soybean. AFLP analysis of four soybean near-isogenic lines (NILs) identified three AFLP markers putatively linked to a virus resistance gene from two sources. The capacity of AFLP analysis to detect thousands of independent genetic loci with minimal cost and time requirements makes them an ideal marker for a wide array of genetic investigations.     

Molecular Characterization of Three Heritiera Species Using AFLP Markers

In the present study three species of Heritiera Aiton (Sterculiaceae) were characterized using 9 amplified fragment length polymorphism (AFLP) primer combinations and the genetic relationship among these three species was assessed, Nine AFLP primer combinations yielded 445 bands out of which 210 were monomorphic and 235 were polymorphic. Out of the 235 polymorphic bands 79 were present only in a single species. Among the total amplified bands 255 were shared between H. fomes and H. littoralis, 225 were shared between H. fomes and H. macrophylla and 306 bands were shared between H. littoralis and H. macrophylla. The cluster analysis showed H. littoralis is closer to H. macrophylla than H. fomes. The similarity between H. fomes and H. littoralis was higher than that of H. fomes and H. macrophylla. The present study indicates that H. littoralis is better classified as mangrove associate or back mangal than a true mangrove. This revised version was published online in July 2006 with corrections to the Cover Date.