Cepa Aggregatum Group Research Articles

Vegetative response of shallot (Allium cepa Aggregatum group) bulbs on vernalization and gibberellin treatment in different environments

This research is an initial study of the effects of vernalization and Gibberellins in two different environments. The research was conducted in a split-split plot design with three factors and three times repetition. The main plot was the environment (environment 1, environment 2), the split plot was vernalization temperature (3±2 and 9±2°C), and split-split plot was Gibberellin concentration (0, 50, 100, 150 ppm). The result showed that the vernalizations and Gibberellin have significantly affected plant height (p<0.01). The environment significantly affected plant height, number of tillers, and number of leaves. There was an interaction between Gibberellin and environment treatment on plant height and an interaction between vernalization, Gibberellin, and environment on the number of leaves. The environment with temperature: 29±2.18°C, RH: 45±9.14%, light intensity: 9272±7669 μmol m-2 S-1 showed plant height and the number of tillers higher than other environments, contrary to the number of leaves. According to the principal component analysis, this environment is more suitable for all vernalization and Gibberellin treatments than other environments. The results of this study indicate that the environment more influences vegetative growth than the other two treatments.

The Phytochemical and Nutritional Composition of Shallot Species (Allium × cornutum, Allium × proliferum and A. cepa Aggregatum) Is Genetically and Environmentally Dependent.

Shallots are a perennial plant from the Alliaceae family, classified with the common onion under the name of the Allium cepa Aggregatum group. The term shallot is also used for diploid and triploid viviparous onions, known as Allium × proliferum (Moench) Schrad and Allium × cornutum Clementi ex Vis., respectively. In this study, we compared the dry matter, pyruvic acid content, sugar content, flavonoid content, antioxidant capacity and mineral composition of 34 shallot accessions falling into three shallot species (Allium × cornutum, Allium × proliferum and A. cepa Aggregatum). Shallot accessions belonging to the A.× cornutum and A. × proliferum groups are characterized by high dry matter content (around 25%), of which a little less than 50% is formed of inulin-type sugars, polysaccharides, considered an excellent prebiotic with beneficial effects on human health. On the other hand, accessions belonging to the A. cepa Aggregatum group have lower dry matter content and, as a result, lower pungency (measured as pyruvic acid content), making them more suitable for fresh consumption by a broader range of consumers, but, at the same time, abundant in phenolic compounds, especially quercetin and isorhamnetin glycosides. We also observed a greater biodiversity among accessions within the A. cepa Aggregatum group in all the analyzed physico-chemical parameters compared to the other shallot groups. The investigated shallot accessions have an excellent in vitro antioxidant capacity, as well as excellent nutritional properties.

Construction of a high-density linkage map and graphical representation of the arrangement of transcriptome-based unigene markers on the chromosomes of onion, Allium cepa L.

BackgroundGenomic information for Allium cepa L. is limited as it is heterozygous and its genome is very large. To elucidate potential SNP markers obtained by NGS, we used a complete set of A. fistulosum L.-A. cepa monosomic addition lines (MALs) and doubled haploids (DHs). These were the parental lines of an A. cepa mapping population for transcriptome-based SNP genotyping.ResultsWe mapped the transcriptome sequence reads from a series of A. fistulosum-A. cepa MALs onto the unigene sequence of the doubled haploid shallot A. cepa Aggregatum group (DHA) and compared the MAL genotype call for parental bunching onion and shallot transcriptome mapping data. We identified SNP sites with at least four reads on 25,462 unigenes. They were anchored on eight A. cepa chromosomes. A single SNP site was identified on 3,278 unigenes and multiple SNPs were identified on 22,184 unigenes. The chromosome marker information was made public via the web database Allium TDB (http://alliumtdb.kazusa.or.jp/). To apply transcriptome based genotyping approach for genetic mapping, we gathered RNA sequence data from 96 lines of a DHA × doubled haploid bulb onion A. cepa common onion group (DHC) mapping population. After selecting co-dominant SNP sites, 16,872 SNPs were identified in 5,339 unigenes. Of these, at least two SNPs with identical genotypes were found in 1,435 unigenes. We developed a linkage map using genotype information from these unigenes. All unigene markers mapped onto the eight chromosomes and graphical genotyping was conducted based on the unigene order information. Another 2,963 unigenes were allocated onto the eight chromosomes. To confirm the accuracy of this transcriptome-based genetic linkage map, conventional PCR-based markers were used for linkage analysis. All SNP - and PCR-based markers were mapped onto the expected linkage groups and no inconsistency was found among these chromosomal locations.ConclusionsEffective transcriptome analysis with unique Allium resources successfully associated numerous chromosome markers with unigene information and a high-density A. cepa linkage map. The information on these unigene markers is valuable in genome sequencing and useful trait detection in Allium.

Shallot Species and Subtypes Discrimination Based on Morphology Descriptors.

Shallots are an edible Alliaceous crop representing a group of genetically and morphologically different species. Shallot species determination is rather complex due to the high variability in phenotypes within a single species. Flower morphology has been successfully employed in shallot species determination; however, shallot florogenesis depends upon many genetic and environmental factors. There is a need for more accessible morphological descriptors used in shallot species determination, since flowering in shallot may not be consistent. In this study, we investigated the discriminating power of shallot vegetative and bulb morphology descriptors. European Cooperative Programme for Plant Genetic Resources morphology descriptors were used for describing 35 Croatian shallot accessions. The proposed methodology based on vegetative and bulb morphological descriptors could be used for shallot species discrimination. Additionally, two subtypes of A. cepa Aggregatum group were identified in this study: the first being the shallot type (1) and a potato onion type (2), which differed based on bulb morphology descriptors (bulb shape, bulb skin color, and a number of bulblets).

Morphological and Biochemical Diversity of Shallot Landraces Preserved Along the Croatian Coast.

Shallots are a valuable minor Allium crop, and are propagated vegetatively and maintained in home gardens across generations along the Croatian coast and island areas. Shallot landraces growing along the Croatian coast fall into three genotypes: Allium cepa Aggregatum group (2n = 2x = 16), A. × proliferum (Moench) Schard. (2n = 2x = 16), and A. × cornutum Clementi ex Vis. (2n = 3x = 24), among which A. × cornutum is the most widespread. The aim of this study was to differentiate shallot accessions collected from local farmers using morphological markers. Also, the chemical composition including phenolic content, phenolic profile, total antioxidant capacity, and mineral composition, of shallot accessions was compared with that of the local landraces of common onion, and with market available shallot and common onion cultivars. Based on morphological observations and using multivariate classification, shallot landraces were classified into three distinct groups. Properties, based on which A. × cornutum can be differentiated from A. cepa Aggregatum and A. × proliferum, are stamen morphology, stamen length, leaf and scape vegetative properties, number of bulbs in cluster, cluster mass, and bulb diameter. Flower diameter and flower pedicel length differentiate A. × cornutum and A. × proliferum from A. cepa Aggregatum. Significant variability was observed in the biochemical profiles across tested accessions. Compared with the commercial common onion cultivars, local shallot accessions have higher bulb N, P, and K content. The major phenolic compounds identified in shallots were quercetin-4′-glucoside and quercetin-3,4′-diglucoside. Additionally, several other minor phenolic compounds were also identified. Morphological and biochemical profiles were evaluated using Partial Least Square (PLS) analysis. Specific morphological traits and biochemical markers for possible species identification are proposed.

Correction: RNA-sequencing-based transcriptome and biochemical analyses of steroidal saponin pathway in a complete set of Allium fistulosum-A. cepa monosomic addition lines.

[This corrects the article DOI: 10.1371/journal.pone.0181784.].

RNA-sequencing-based transcriptome and biochemical analyses of steroidal saponin pathway in a complete set of Allium fistulosum-A. cepa monosomic addition lines.

The genus Allium is a rich source of steroidal saponins, and its medicinal properties have been attributed to these bioactive compounds. The saponin compounds with diverse structures play a pivotal role in Allium’s defense mechanism. Despite numerous studies on the occurrence and chemical structure of steroidal saponins, their biosynthetic pathway in Allium species is poorly understood. The monosomic addition lines (MALs) of the Japanese bunching onion (A. fistulosum, FF) with an extra chromosome from the shallot (A. cepa Aggregatum group, AA) are powerful genetic resources that enable us to understand many physiological traits of Allium. In the present study, we were able to isolate and identify Alliospiroside A saponin compound in A. fistulosum with extra chromosome 2A from shallot (FF2A) and its role in the defense mechanism against Fusarium pathogens. Furthermore, to gain molecular insight into the Allium saponin biosynthesis pathway, high-throughput RNA-Seq of the root, bulb, and leaf of AA, MALs, and FF was carried out using Illumina's HiSeq 2500 platform. An open access Allium Transcript Database (Allium TDB, http://alliumtdb.kazusa.or.jp) was generated based on RNA-Seq data. The resulting assembled transcripts were functionally annotated, revealing 50 unigenes involved in saponin biosynthesis. Differential gene expression (DGE) analyses of AA and MALs as compared with FF (as a control) revealed a strong up-regulation of the saponin downstream pathway, including cytochrome P450, glycosyltransferase, and beta-glucosidase in chromosome 2A. An understanding of the saponin compounds and biosynthesis-related genes would facilitate the development of plants with unique saponin content and, subsequently, improved disease resistance.

Shallots in Croatia – genetics, morphology and nomenclature

Abstract - The term 'shallot' in Croatia denotes three genetically and morphologically different, vegetatively reproduced relatives of the common onion, Allium cepa L., which are mainly traditionally cultivated for consumption and as a spice: A. cepa Aggregatum group, (2n = 2x = 16), A. × proliferum (Moench) Schrad. (2n = 2x = 16) and A. × cornutum Clementi ex Vis. (2n = 3x = 24). This paper reviews the results of studies of their morpho- -anatomical characteristics and genetic structure. Although all three taxa were determined as varieties of the common onion, only the shallot A. cepa Aggregatum group (syn. A. ascalonicum L.) belongs to that species. The shallot A. × proliferum represents a hybrid between the two closely related species, A. cepa and A. fistulosum L. The third form of shallot, A. × cornutum is a still incompletely understood triploid hybrid between A. cepa and one or two closely related Allium species, whose identity has not been fully elucidated. In contrast to shallot A. cepa Aggregatum group, which has normal meiosis and produces fertile seed, hybrid shallots A. × proliferum and A. × cornutum are sterile, and reproduce exclusively vegetatively by underground bulbs or bulbils from the inflorescence.

Discovery of a new source of resistance to Fusarium oxysporum, cause of Fusarium wilt in Allium fistulosum, located on chromosome 2 of Allium cepa Aggregatum group

This study was carried out to evaluate the antifungal effect of Allium cepa Aggregatum group (shallot) metabolites on Fusarium oxysporum and to determine the shallot chromosome(s) related to Fusarium wilt resistance using a complete set of eight Allium fistulosum - shallot monosomic addition lines. The antifungal effects of hexane, butanol, and water extraction fractions from bulbs of shallot on 35 isolates of F. oxysporum were examined using the disc diffusion method. Only hexane and butanol fractions showed high antifungal activity. Shallot showed no symptom of disease after inoculation with F. oxysporum f. sp. cepae. The phenolic content of the roots and the saponin content of root exudates of inoculated shallot increased to much higher levels than those of the control at 3 days after inoculation. Application of freeze-dried shallot root exudates to seeds of A. fistulosum soaked in a spore suspension of F. oxysporum resulted in protection of seedlings against infection. Among eight monosomic addition lines and A. fistulosum, FF+2A showed the highest resistance to Fusarium wilt. This monosomic addition line also showed a specific saponin band derived from shallot on the thin layer chromatography profile of saponins in the eight monosomic addition lines. The chromosome 2A of shallot might possess some of the genes related to Fusarium wilt resistance.

Biochemical and Genetic Analysis of Carbohydrate Accumulation in Allium cepa L

Onion and shallot (Allium cepa L.) exhibit wide variation in bulb fructan content, and the Frc locus on chromosome 8 conditions much of this variation. To understand the biochemical basis of Frc, we conducted biochemical and genetic analyses of Allium fistulosum (FF)-shallot (A. cepa Aggregatum group) alien monosomic addition lines (AALs; FF+1A-FF+8A) and onion mapping populations. Sucrose and fructan levels in leaves of FF+2A were significantly lower than in FF throughout the year, and the springtime activity of acid invertase was also lower. FF+8A showed significantly higher winter sucrose accumulation and sucrose phosphate synthase (SPS) activity. Inbred high fructan (Frc_) lines from the 'W202Ax Texas Grano 438' onion population exhibited significantly higher sucrose levels prior to bulbing than low fructan (frcfrc) lines. Sucrose synthase (SuSy) activity in these lines was correlated with leaf hexose content but not with Frc phenotype. Markers for additional candidate genes for sucrose metabolism were obtained by cloning a major SPS expressed in onion leaf and exhaustively mining onion expressed sequence tag resources. SPS and SuSy loci were assigned to chromosome 8 and 6, respectively, using AALs and linkage mapping. Further loci were assigned, using AALs, to chromosomes 1 (sucrose phosphate phosphatase), 2 (SuSy and three invertases) and 8 (neutral invertase). The concordance between chromosome 8 localization of SPS and elevated leaf sucrose levels conditioned by high fructan alleles at the Frc locus in bulb onion or alien monosomic additions of chromosome 8 in A. fistulosum suggest that the Frc locus may condition variation in SPS activity.

Chromosomal Locations of Microsatellites in Onion

Bulb onion (Allium cepa L.) has a very large genome composed of a high proportion of repetitive DNAs. Genetic analyses of repetitive sequences may reveal microsatellites in order to increase the number of genetic markers in onion. Thirty microsatellites were previously isolated from an onion genomic library (Fischer and Bachmann, 2000). A complete set of Japanese bunching onion (A. fistulosum) – shallot (A. cepa Aggregatum group) monosomic addition lines were used to assign these microsatellites to the chromosomes of A. cepa. Simplified PCR conditions for each microsatellite were determined and 28 of the 30 primer pairs amplified DNA fragments, of which 21 microsatellite markers were assigned to chromosomes of A. cepa. Subsequent mapping of these microsatellites will enable us to establish the chromosomal distribution of these markers.

Production and characterization of alien chromosome additions in shallot (Allium cepa L. Aggregatum group) carrying extra chromosome(s) of Japanese bunching onion (A. fistulosum L.)

First and second backcrosses of amphidiploid hybrids (2n = 4x = 32, genomes AAFF) between shallot (Allium cepa Aggregatum group) and A. fistulosum were conducted to produce A. cepa - A. fistulosum alien addition lines. When shallot (A. cepa Aggregatum group) was used as a pollinator, the amphidiploids and allotriploids set germinable BC(1) and BC(2) seeds, respectively. The 237 BC(1) plants mainly consisted of 170 allotriploids (2n = 3x = 24, AAF) and 42 hypo-allotriploids possessing 23 chromosomes, i.e., single-alien deletions (2n = 3x-1 = 23, AAF-nF). The single-alien deletions in the BC(1) progeny showed dwarfing characteristics and were discriminated from the allotriploids (2n = 24) and hyper-allotriploids (2n = 25) by means of flow cytometric analysis. The chromosome numbers of 46 BC(2) seedlings varied from 16 to 24. Eight monosomic additions (2n = 2x+1 = 17, AA+nF) and 20 single-alien deletions were found in these BC(2) seedlings. Consequently, six kinds of A. cepa - A. fistulosum alien chromosome additions possessing different chromosome numbers (2n = 17, 18, 20, 21, 22, 23) were recognized in the BC(1) and BC(2) populations. A total of 79 aneuploids, including 62 single-alien deletions, were analyzed by a chromosome 6F-specific isozyme marker (Got-2) in order to recognize its existence in their chromosome complements. This analysis revealed that two out of 62 single-alien deletions did not possess 6F. One (AAF-6F) out of the possible eight single-alien deletions could be identified at first. The present study is a first step toward the development of a useful tool, such as a complete set of eight different single-alien deletions, for the rapid chromosomal assignment of genes and genetic markers in A. fistulosum.

Effect of single alien chromosome from shallot (Allium cepa L. Aggregatum group) on carbohydrate production in leaf blade of bunching onion (A. fistulosum L.)

We used a complete set of Allium fistulosum - shallot (A. cepa Aggregatum group) monosomic addition lines (FF+1A - FF+8A) to identify shallot chromosomes affecting the production of sugars. In the alien addition lines grown over two years in an experimental field at Yamaguchi University (34 degrees N, 131 degrees E), shallot chromosomes 2A and 8A altered sugar contents in leaf-bunching onion (A. fistulosum). Except for FF+2A, every monosomic addition accumulated non-reducing sugars in winter leaf blades. FF+8A caused an increase in the amounts of non-reducing sugars in the winter. FF+2A hardly produced non-reducing sugar throughout the two-year study. These results indicated that genes related to non-reducing sugar metabolism are located on the 2A and 8A chromosomes. The results of regression analyses using 2002 data on A. fistulosum and the monosomic addition set revealed a correlation (r = 0.63 +/- 0.07; mean +/- SE., n = 9) between reducing sugar and monosaccharide (Glc+Fru) contents but no correlation between non-reducing sugar and sucrose contents. This result indicates the existence of other polysaccharides (e.g., scorodose) as non-reducing sugars in the leaf blade.

Fertility of Alien Monosomic Addition Lines of Japanese Bunching Onion (Allium fistulosum L.) with Extra Chromosomes from Shallot (A. cepa L. Aggregatum group).

In a series of alien monosomic addition lines (AMALs ; FF+1A-FF+8A) of Japanese bunching onion (Allium fistulosum L.) with extra chromosomes from shallot (A. cepa L. Aggregatum group), seed and pollen fertility were assessed to reveal the effect of the alien chromosomes on the fertility of the recipient species. Data for seed fertility which were derived from three styles of pollination (open pollination, selfing, and backcrossing with A. fistulosum) yielded considerable variations among types of the AMALs. FF+8A had high seed fertility, whereas FF+3A had very low one. Pollen grains with normal number and shape of nuclei were observed in all types of the AMALs, but pollen fertility varied among the types. Particularly, FF+4A had high pollen fertility (approx. 80%), whereas FF+1A expressed very low pollen fertility (approx. 31%). These results indicate that alien chromosomes remarkably influence both seed and pollen fertility of the recipient species. A regression analysis revealed that there was no correlation between seed and pollen fertility in the AMALs. This indicates that genes related to the destinies of seed and pollen in the AMALs are located respectively on different chromosome of A. cepa Aggregatum group.

Chromosomal locations of genes related to flavonoid and anthocyanin production in leaf sheath of shallot. Allium cepa L. Aggregatum group.

High-performance liquid chromatography (HPLC) analyses using a series of alien monosomic addition lines (AMALs) of Japanese bunching onion (Allium fistulosum L.) having extra chromosomes from shallot (A. cepa L. Aggregatum group) were performed to determine the chromosomal locations of the genes for flavonoid and anthocyanin production in leaf sheaths of A. cepa Aggregatum group. In HPLC profiles both at 360 and 520 nm, several peaks were observed in A. cepa Aggregatum group and AMAL with chromosome 5A from A. cepa Aggregatum group but no peak was observed in A. fistulosum and other AMALs. Four of the compounds observed at 360 nm were identified as known flavonoids, i.e., apigenin, kaempferol, quercetin, and rutin. Five out of the total 18 compounds at 520 nm were identified as known anthocyanins, i.e., cyanidin-3-glucoside, cyanidin-3-laminariobioside, peonidin-3-glucoside, cyanidin-3-malonylglucoside, and cyanidin-3-malonyllaminariobioside. These results reveal that a group of the genes related to the flavonoid and anthocyanin production in the leaf sheath of A. cepa Aggregatum group are located on the chromosome 5A.

Assignment of randomly amplified polymorphic DNA markers to all chromosomes of shallot (Allium cepa L. Aggregatum group).

The chromosomal locations of randomly amplified polymorphic DNA (RAPD) markers were examined in shallot (Allium cepa L. Aggregatum group). A series of alien monosomic addition lines of Japanese bunching onion (A. fistulosum L.) with extra chromosomes (1A-8A) from A. cepa Aggregatum group was used as plant materials. Several decamer (OPERON KITs A, E, and G) and 12-mer (Wako DNA Oligomer sets A-1, C-4, F-4, and F-5) oligonucleotides were applied as random primers. The chromosomal locations of the 16 RAPD markers were determined; the RAPD marker OPE091600 was located on the chromosome 1A of A. cepa Aggregatum group, OPE03600 and OPE181400 on 2A, OPA12700 on 3A, OPA11950, OPE181500, OPG10800, WAA091800, WAF65900, and WAF83800 on 4A, OPE17500 and OPE182000 on 5A, OPG08500 on 6A, WAF812800 and WAF832200 on 7A, and WAC68500 on 8A. Consequently, the RAPD markers were assigned to all the chromosomes of A. cepa Aggregatum group.

Morphological characteristics of a series of alien monosomic addition lines of Japanese bunching onion (Allium fistulosum L.) with extra chromosomes from shallot (A. cepa L. Aggregatum group).

To study the effect of the extra chromosomes on morphological characters both in vegetative and reproductive stages, a series of alien monosomic addition lines of Japanese bunching onion (Allium fistulosum L.) with extra chromosomes from shallot (A. cepa L. Aggregatum group) were grown in the experimental farm of Saga University, Saga, Japan. Several morphological characters of the alien monosomic addition lines were found to be specific for the respective alien chromosomes from A. cepa Aggregatum group. The most distinctive characteristics in each alien monosomic addition line were as follows; spheroidal spathe in FF+1A, bloom-less leaf blade in FF+2A, slow expansion of leaf in FF+3A, acuminate spathe in FF+4A, reddishyellow leaf sheath in FF+5A, arch-like leaf brade in FF+6A, fast expansion of leaf in FF+7A, and intensely yellow anther in FF+8A. The results indicate that these character expressions are deeply related to alien genes on extra chromosomes from A. cepa Aggregatum group.

Establishment of a series of alien monosomic addition lines of Japanese bunching onion (Allium fistulosum L.) with extra chromosomes from shallot (A. cepa L. aggregatum group).

Forty one plants of alien monosomic addition lines of Allium fistulosum L. with extra chromosomes from A. cepa L. Aggregatum group (FF + nA) were produced through the second backcross of amphidiploids between these two species to A. fistulosum. Identification of the extra chromosomes in the 16 plants by elaborate karyotype analyses indicate that a complete series (eight different types) of the alien monosomic addition lines was established in Allium for the first time in this study. Chromosomal locations of malate dehydrogenase (MDH) gene, triosephosphate isomerase (TPI) gene and 5S rDNA of A. cepa Aggregatum group were determined using the series; The gene locus Mdh-1 was located on 4A, Tpi-1 on 3A and a 5S rDNA locus on 7A. Our previous and present studies using the alien monosomic addition lines revealed 11 genetic markers (isozyme and 5S rDNA) assigned to all eight chromosomes of A. cepa Aggregatum group, and these markers reconfirmed the completion of the series. Extra chromosomes of 25 other plants were examined by means of simple analyses of the chromosome markers and karyotypes. Of the total 41 plants, frequencies of the alien monosomic addition lines with extra chromosomes 1A to 8A were as follows: 1A, 5 plants; 2A, 3; 3A, 5; 4A, 9; 5A, 4; 6A, 2; 7A, 11; and 8A, 2.

葉緑体DNAのRFLP分析によるワケギの母親および父親植物の同定

Previous cytogenetic studies revealed that Allium wakegi Araki has a hybrid origin and its parental plants are A. fistulosum L. and A. cepa L. Aggregatum group. In order to trace the origin of the cytoplasm of A. wakegi and to identify its maternal and paternal plants, restriction fragment length polymorphisms (RFLPs) were studied in the chloroplast DNAs of A. fistulosum, A. cepa Aggregatum group, their reciprocal hybrids and A. wakegi Interspecific RFLPs were clearly observed between A. fistulosum and A. cepa Aggregatum group with four restriction enyzmes, Sma I, Pvu II, Xho I and Bgl II. The reciprocal interspecific hybrids showed the restriction patterns similar to those of the maternal plants. All the clones of A. wakegi, collected from Japan, Korea, China, Taiwan and Myanmar, showed restriction patterns quite similar to those of A. fistulosum without exception. These results establish that the maternal and paternal plants of A. wakegi are A. fistulosum and A. cepa Aggregatum group, respectively.

Genetic Analyses of Glutamate Dehydrogenase Isozymes in Cultivated and Wild Species of Section Cepa in Allium.

Glutamate dehydrogenase (GDH) was studied to establish the genetic system of GDH isozymes in section Cepa of Allium. Detailed analyses of the GDH zymograms of the diploid and triploid hybrids between A. fistulosum and A. cepa Aggregatum group revealed that the degree of association of the GHD subunit varied from monomer to hexamer. The GDH expressions in the two cultivated and four wild species used in this study were governed by two alleles Gdh-1F and Gdh-1A at a single locus (Gdh-1). In A. fistulosum, A. galanthum, A. oschaninii and A. altaicum, the allele Gdh-1F was observed, while Gdh-1A was noticed in A. cepa Aggregatum group, A. cepa Common onion group and A. vavilovii. These results indicate that the GDH isozyme genes are useful genetic markers in section Cepa.