Lectotypification of two Musa sections (Musaceae)

The present work is part of a continuing study to revise the old names in Musa and aims to clarify the taxonomy in the sections Rhodoclamys and Callimusa. Lectotypes are designated here for Musa sect. Callimusa and M. sect. Rhodochlamys . These sections were first erected without the indication of a type species.     

Analysis of genetic diversity and sectional relationships in Musa using AFLP markers

The AFLP technique was used to assess the genetic diversity and sectional relationships in 39 accessions representing the four main sections of the genus Musa. Eight AFLP + 3 primer pairs produced 260 polymorphic bands that were used in cluster and PCO analysis. A wide range of variability was observed among the species within the sections of the genus Musa. AFLP data was useful in separating the different sections of the genus as well as differentiating the different genomic groups of section Eumusa. Section Rhodochlamys (x = 11) appeared as a distinct entity and clustered closely with the Musa acuminata Colla complex of section Eumusa that has the same basic chromosome number. This relationship is congruent with previous studies. However, unlike previous proposals that questioned the identity of Rhodochlamys as a separate taxonomic unit, PCO analysis of the AFLP data showed that it is a distinct entity. Musa laterita Cheesman (Rhodochlamys) and Musa schizocarpa Simmonds clustered with the M. acuminata complex suggesting that they may be sources of useful genes for the improvement of the cultivated bananas. Callimusa formed a distinct unit and was closer to Australimusa than to the other sections. Although both sections share the same basic chromosome number of x = 10 these sections are genetically distinct     

Genetic Diversity in Musa acuminata Colla and Musa balbisiana Colla and some of their natural hybrids using AFLP Markers

Genetic diversity and relationships were assessed in 28 accessions of Musa acuminata (AA) Colla and Musa balbisiana (BB) Colla, and some of their natural hybrids, using the amplified fragment length polymorphisms (AFLP) technique. Fifteen AFLP +3 primer pairs produced 527 polymorphic bands among the accessions. Neighbor-joining and principal co-ordinate (PCO) analyses using Jaccard's similarity coefficient produced four major clusters that closely corresponded with the genome composition of the accessions (AA, BB, AAB and ABB). The AFLP data distinguished between the wild diploid accessions and suggested new subspecies relationships in the M. acuminata complex that are different from those based on morphological data. The data suggested that there are three subspecies within the M. acuminata complex (ssp. burmannica Simmonds, malaccensis Simmonds, and microcarpa Simmonds). 'Tjau Lagada' (ssp. microcarpa), 'Truncata' [ssp truncata (Ridl.) Shepherd] and 'SF247' [ssp. banksii (F.Muell) Simmonds] clustered very closely with 'Gros Michel' and 'Km 5', indicating that more than one M. acuminata subspecies may be involved in the origin of triploid AAA bananas. 'Calcutta 4' (ssp. burmannicoides De Langhe &; Devreux) and 'Long Tavoy' (ssp. burmannica) were closely related and could be together in the same subspecies. This study also showed that there is much more genetic diversity within M. balbisiana that was split into two groups: (1) 'I-63' and 'HND' and (2) 'Los Banos', 'MPL' (Montpellier), '10852', 'Singapuri', 'Etikehel', and 'Butohan 1' as the other.     

Assessment of genetic diversity of Korean native pig (Sus scrofa) using AFLP markers

In order to assess the genetic diversity and genetic relationships among the six commercial pig breeds including the Korean native pig, we performed an amplified fragment length polymorphism (AFLP) analysis. Applying the three EcoRI/TagI primer combinations to 54 individual pig samples out of six breeds, a total of 186 AFLP bands were generated, 67 (36%) of which were identified as polymorphic bands. From these polymorphic bands, the three estimates (percentage of polymorphic loci, Neis heterozygosity and Shannon index) of genetic diversity, G(ST) estimates, Neis unbiased genetic distance and two indices of genetic similarity were calculated. From all the calculations of genetic diversity, the lowest genetic diversity was exhibited in the Korean native pig, and the highest in the Chinese Yanbian pig. Given the mean G(ST) value (G(ST) = 0.390) across all pigs examined, levels of apparent breed subdivision were considerable. A UPGMA tree of individuals based on Jaccards similarity index showed that the Korean native pig formed a distinct cluster from the other five pigs. In addition, the tree displayed that all the individuals except for six individuals were grouped into their breeds. Principal component analysis based on the binary data matrix of either presence or absence confirmed the distinctness of the Korean native pig from the other pigs. Our results indicate that the Korean native pig has a low level of genetic diversity and is distinct from the five pig breeds, confirming the results from previous microsatellite data. The findings also suggest that AFLP analysis may be a valuable tool for revealing genetic relationships and genetic diversity among different pig breeds.     

Assessment of genetic diversity in Azadirachta indica using AFLP markers

 Genetic diversity was estimated in 37 neem accessions from different eco-geographic regions of India and four exotic lines from Thailand using AFLP markers. Seven AFLP selective primer combinations generated a total of 422 amplification products. The average number of scorable fragments was 60 per experiment, and a high degree (69.8%) of polymorphism was obtained per assay with values ranging from 58% to 83.8%. Several rare and accession-specific bands were identified which could be effectively used to distinguish the different genotypes. Genetic relationships within the accessions were evaluated by generating a similarity matrix based on the Jaccard index. The phenetic dendrogram generated by UPGMA as well as principal correspondence analysis separated the 37 Indian genotypes from the four Thai lines. The cluster analysis indicated that neem germplasm within India constitutes a broad genetic base with the values of genetic similarity coefficient ranging from 0.74 to 0.93. Also, the Indian genotypes were more dispersed on the principal correspondence plot, indicating a wide genetic base. The four lines from Thailand, on the other hand, formed a narrow genetic base with similarity coefficients ranging from 0.88 to 0.92. The lowest genetic similarity coefficient value (0.47) was observed between an Indian and an exotic genotype. The level of genetic variation detected within the neem accessions with AFLP analysis suggests that it is an efficient marker technology for delineating genetic relationships amongst genotypes and estimating genetic diversity, thereby enabling the formulation of appropriate strategies for conservation and tree improvement programs. Received: 20 October 1998 / Accepted: 28 November 1998     

蕉类的细胞遗传学研究

本文对芭蕉属正蕉组内的一些有代表性的野生种和包括香蕉,大蕉在内的二倍体和三倍体食用栽培蕉,共１８个材料进行了核型比较分析,对其中５个重要的栽培蕉品种的花粉母细胞减数分裂进行了观察,从核型、染色体配对以及染色体 特殊分离行为等３个方面得到的证据表明,并非所有香蕉才同源三倍体,有一些香蕉品种的３个染色体组之间同源程度很低, 通过对一些特征染色体的分析,推测这种香蕉的单染色体组很可能来自ＢＢ野生蕉、大蕉     

Assessment of genetic diversity among and within Achillea species using amplified fragment length polymorphism (AFLP)

Amplified fragment length polymorphism (AFLP) markers were used to assess the genetic diversity of 57 Achillea accessions belonging to five species, A. millefolium, A. filipendulina, A. tenuifolia, A. santolina and A. biebersteinii. Nine AFLP primer combinations were used, which produced 301 polymorphic bands. In most species, a high level of genetic variation was detected among the genotypes. The Jaccard's similarity indices (J), based on AFLP profiles, were subjected to UPGMA cluster analysis. Application of Mantel's test for cophenetic correlation to the cluster analysis indicated the high fitness of the accessions to a group (r = 0.918). The dendrogram generated revealed five major groups corresponding to five species. The principle coordinate analysis (PCoA) data confirmed the results of the clustering. Among the species, A. teunifolia and A. santolina showed the greatest and the least genetic diversity, respectively. A. filipendulina accessions were acquired primarily from the same ecological regions of western Iran. Accessions belonging to A. biebersteinii originated from the Isfahan province and were separated from other species at the root of the dendrogram. The results of the clustering method, based on AFLP markers, corresponded closely with the geographical origins of the genotypes. The results of the present study could contribute to a better understanding and management of conservation and exploitation of the Achillea germplasm.     

Genetic Diversity of the Wild Banana Musa acuminata Colla in Malaysia as Evidenced by AFLP

Musa acuminata Colla (Musaceae), the wild progenitor of thecultivated banana, is highly variable in Malaysia and presentsseveral unresolved nomenclatural problems. AFLP was employedto distinguish among three subspecies of Musa acuminata(subsp.truncata and subsp. malaccensis from peninsular Malaysia andsubsp. microcarpa from Borneo) and to examine whether subsp.truncata is a distinct taxon. Eight primer combinations revealedmolecular markers specific for each of the three taxa. UPGMAcluster analysis showed the three taxa were distinct. Subspeciesmalaccensis which is endemic in peninsular Malaysia and subsp.microcarpa which is endemic in Borneo were found to be moresimilar to each other in their DNA patterns than they are tosubsp. truncata, which is endemic to peninsular Malaysia. Sincesubsp. truncata is genetically separate from subsp. malaccensisand subsp.microcarpa , it cannot be regarded as synonymous witheither of these subspecies. This paper sheds light on the nomenclatureof the three subspecies of Musa acuminata. Copyright 2001 Annalsof Botany Company Musa acuminata Colla, truncata, malaccensis, microcarpa, Musaceae, wild banana, genetic diversity, AFLP, DNA fingerprinting     

Genetic Diversity and Population Assessment of Musa L. (Musaceae) Employing CDDP Markers

Plant Molecular Biology Reporter - Sixty-six accessions of Musa genus with different genomic groups that consisted of wild relatives and cultivated lines were obtained from the International...     

Assessment of genetic diversity in a Morus germplasm collection using fluorescence-based AFLP markers

To meet various breeding objectives and to conserve the existing genetic resources of mulberry for future use, the present study was undertaken to investigate the amount of genetic diversity and to establish the relationships between mulberry genotypes using fluorescence-based AFLP markers. Genetic diversity was estimated in 45 mulberry accessions from different eco-geographic regions of Japan and other parts of the world. Five primer combinations amplified an average of 110 AFLP markers per primer combination, ranging in size from 35 to 500 bp. A high degree of polymorphism was revealed by these combinations that ranged from 69.7 to 82.3% across all the genotypes studied. Several rare genotype-specific bands were also identified which could be effectively utilized to distinguish different genotypes. The wide range in genetic similarity coefficients (0.58–0.99) indicated that the mulberry germplasm collection represents a genetically diverse popu-lation. The phenetic dendrogram generated by the UPGMA method grouped 45 accessions into four major clusters, which was in agreement with the results from conventional methods. Clustering of some genotypes into strictly separate groups was not readily apparent and no clear interrelationships could be depicted, in spite of their different geographic origin. In addition, AFLP analysis provided sufficient polymorphism for DNA typing and contributed additional insights into the genetic structure of the mulberry germplasm. These results will help in the formulation of appropriate strategies for conservation and variety improvement in mulberry, for which little or no knowledge of genetic diversity is currently available. Received: 30 December 1999 / Accepted: 14 March 2000     

Intra-species DNA polymorphism in the tobacco cyst-nematode complex (Globodera tabacum) using AFLP.

Amplified fragment length polymorphism (AFLP) was used to obtain information on the within-species genetic variability of the tobacco cyst-nematode (TCN) complex. AFLP was found to be well suited to this type of study. The current classification of TCN was confirmed. Results indicate that the Globodera tabacum solanacearum group, believed to be restricted to the U.S.A., also occurs in Mexico. The within-species variability of TCN is considerable. Populations from Mexico may form a new subgroup. AFLP group-specific markers were identified for two of the TCN subgroups: Globodera tabacum tabacum and Globodera tabacum solanacearum.     

Genetic diversity of Hibiscus tiliaceus (Malvaceae) in China assessed using AFLP markers

Amplified fragment length polymorphism (AFLP) markers were used to investigate the genetic variations within and among nine natural populations of Hibiscus tiliaceus in China. DNA from 145 individuals was amplified with eight primer pairs. No polymorphisms were found among the 20 samples of a marginal population of recent origin probably due to a founder effect. Across the other 125 individuals, 501 of 566 bands (88.5%) were polymorphic, and 125 unique AFLP phenotypes were observed. Estimates of genetic diversity agreed with life history traits of H. tiliaceus and geographical distribution. AMOVA analysis revealed that most genetic diversity resided within populations (84.8%), which corresponded to results reported for outcrossing plants. The indirect estimate of gene flow based on phiST was moderate (Nm=1.395). Long-distance dispersal of floating seeds and local environments may play an important role in shaping the genetic diversity of the population and the genetic structure of this species.     

西藏地区雪层杜鹃遗传多样性的AFLP分析

采用AFLP技术对西藏地区雪层杜鹃（Rhododendron nivale）5个天然种群135份材料进行遗传多样性和遗传分化研究。筛选得出的6对引物共扩增产物273条DNA片段,扩增多态位点百分率为85.71%。5个雪层杜鹃种群的遗传多样性指标表现了相似的变化趋势,Nei基因多样性指数（h）和Shannon信息指数（I）的变化趋势一致,均为工布江达县种群 < 米林种群 < 嘎隆拉种群 < 色季拉山种群 < 红拉山种群。POPGENE分析结果表明雪层杜鹃在物种水平（PPL=85.71%,I=0.415 1,h=0.273）具有较高的遗传多样性,种群水平（PPL=62.26%,I=0.280 3,h=0.184 1）的遗传多样性较低。AMOVA分析结果表明36%的遗传变异存在于种群间,64%的遗传变异存在于种群内,雪层杜鹃种群间的遗传分化系数（G_st=0.324）与AMOVA分析得到的遗传变异分布结果一致。UPGMA聚类结果说明雪层杜鹃的遗传距离与地理距离和海拔高度没有明显的相关性。综合分析,引起雪层杜鹃的遗传变异的原因可能是地理环境不同和种群的生境类型差异。最后就雪层杜鹃的合理开发和保护提出建议。     

A high-density molecular map for ryegrass (Lolium perenne) using AFLP markers

AFLP markers have been successfully employed for the development of a high-density linkage map of ryegrass (Lolium perenne L.) using a progeny set of 95 plants from a testcross involving a doubled-haploid tester. This genetic map covered 930 cM in seven linkage groups and was based on 463 amplified fragment length polymorphism (AFLP) markers using 17 primer pairs, three isozymes and five EST markers. The average density of markers was approximately 1 per 2.0 cM. However, strong clustering of AFLP markers was observed at putative centromeric regions. Around these regions, 272 markers covered about 137 cM whereas the remaining 199 markers covered approximately 793 cM. Most genetic distances between consecutive pairs of markers were smaller than 20 cM except for five gaps on groups A, C, D, F and G. A skeletal map with a uniform distribution of markers can be extracted from this high-density map, and can be applied to detect and map QTLs. We report here the application of AFLP markers to genome mapping, in Lolium as a prelude to quantitative trait locus (QTL) identification for diverse agronomic traits in ryegrass and for marker-assisted plant breeding. Received: 4 November 1998 / Accepted:15 March 1999     

ATG-anchored AFLP (ATG-AFLP) analysis in cotton

Amplified fragment length polymorphism (AFLP) marker system has had broad applications in biology. However, the anonymous AFLP markers are mainly amplified from non-coding regions, limiting their usefulness as a functional marker system. To take advantages of the traditional AFLP techniques, we propose substitution of a restriction enzyme that recognizes a restriction site containing ATG, called ATG-anchored AFLP (ATG-AFLP) analysis. In this study, we chose NsiI (recognizing ATGCAT) to replace EcoRI in combination with MseI to completely digest genomic DNA. One specific adaptor, one pre-selective primer and six selective amplification primers for the NsiI site were designed for ligation and PCR. Six NsiI and eight MseI primers generated a total of 1,780 ATG-AFLP fragments, of which 750 (42%) were polymorphic among four genotypes from two cultivated cotton species (Upland cotton, Gossypium hirsutum and Pima cotton, G. barbadense). The number of ATG-AFLP markers was sufficient to separate the four genotypes into two groups, consistent with their evolutionary and breeding history. Our results also showed that ATG-AFLP generated less number of total and polymorphic fragments per primer combination (2-3 vs. 4-5) than conventional AFLP within Upland cotton. Using a recombination inbred line (RIL) population, 62 polymorphic ATG-AFLP markers were mapped to 19 linkage groups with known chromosome anchored simple sequence repeat (SSR) markers. Of the nine ATG-AFLP fragments randomly chosen, three were found to be highly homologous to cotton cDNA sequences. An in-silico analysis of cotton and Arabidopsis cDNA confirmed that the ATG-anchored enzyme combination NsiI/MseI did generate more fragments than the EcoRI/MseI combination.     

DNA fingerprinting of Cryptosporidium parvum isolates using amplified fragment length polymorphism (AFLP)

The genetic variability of 10 Cryptosporidium parvum isolates of human and animal origin was investigated using amplified fragment length polymorphism (AFLP). Analysis of fluorescent dye-labeled amplified products was carried out using an ABI PRISMS 377 DNA sequencer and ABI PRISMS GeneScan software. One-hundred and twelve primer combinations were evaluated using a single C. parvum isolate. The patterns generated were highly reproducible. For subsequent study, a subset of 9 primer pairs that yielded 30-90 DNA fragments after the polymerase chain reaction, within the size range of 50-500 bp, was used to screen the 10 C. parvum isolates, including 7 bovine, 1 equine, and 2 of human origin. The animal isolates produced identical fingerprint patterns with every primer combination tested. Of the 2 human isolates tested, 1 of the isolates, passaged in calves, generated the same AFLP DNA banding patterns as the animal isolates, whereas the other isolate, obtained directly from human feces, produced unique patterns. Polymorphism, detected by comparison of the fingerprint patterns of the latter human isolate with the common pattern shared by all other isolates, ranged from 17 to 35% for the 9 primer pairs. The results show that AFLP is a useful method for differentiating C. parvum isolates into 2 distinct genotypes.     

Studies on Mineral Nutrient Uptake using Tissue Culture Derived Plants of Banana (Musa sp)

Banana (Musa sp) plants regenerated from in vitro culture were employed to study varietal differences of ³²P uptake. The results demonstrated that the selected varieties exhibited considerable variation for absorption, translocation and transport index of PO₄ uptake. Use of tissue cultured derived plants can be efficiently utilised to analyse varietal differences in ³²P uptake.