Common Biotypes Research Articles

О применении монопустульных изолятов Puccinia helianthi Schwein. в селекции подсолнечника на устойчивость к ржавчине

A wide distribution of rust on sunflower in the different regions of the Russian Federation caused the necessity to identify races of this disease (Puccinia helianthi) and to conduct breeding on resistance to this obligate parasite. Two methods of inoculation of plants of the lines-differentiators of sunflower resistance were compared: 1) with a mixture of spores of the different uredinia collected on the leaves of an infected plant, and 2) with monopustule isolates (clones of spores from the separate isolated uredinia). The first method is shown to be more appropriate for identification of a racial origin of the field samples of infected sunflower leaves. As being simpler and economic, in a short time, it allows revealing the most common biotypes of a pathogen and identifying a spectrum of races occurring in the studying regions. The second method is necessary for revealing the resistant sunflower genotypes in breeding for resistance to rust. Therefore, it is necessary to create and maintain a working collection of spores of the different races of the pathogen of the various monopustule origin. Identifying monopustule isolates collected from the infected sunflower leaves in the Krasnodar and Saratov region, we determined new races, which were not detected earlier in field samples: 500, 503, 510, 516, and 546. Resistance of the lines HAR 266 and HAR 340 to races of the previous nomenclature (3, 4) was proved under inoculation with the monopustule isolates. However, the biotypes of a rust pathogen with a virulent codes 710 and 747 overcame the resistance of these lines.

Reduced Hippocampal Subfield Volume in Schizophrenia and Clinical High-Risk State for Psychosis.

Magnetic resonance imaging (MRI) studies in schizophrenia demonstrated volume reduction in hippocampal subfields divided on the basis of specific cytoarchitecture and function. However, it remains unclear whether this abnormality exists prior to the onset of psychosis and differs across illness stages. MRI (3 T) scans were obtained from 77 patients with schizophrenia, including 24 recent-onset and 40 chronic patients, 51 individuals with an at-risk mental state (ARMS) (of whom 5 subsequently developed psychosis within the follow-up period), and 87 healthy controls. Using FreeSurfer software, hippocampal subfield volumes were measured and compared across the groups. Both schizophrenia and ARMS groups exhibited significantly smaller volumes for the bilateral Cornu Ammonis 1 area, left hippocampal tail, and right molecular layer of the hippocampus than the healthy control group. Within the schizophrenia group, chronic patients exhibited a significantly smaller volume for the left hippocampal tail than recent-onset patients. The left hippocampal tail volume was positively correlated with onset age, and negatively correlated with duration of psychosis and duration of medication in the schizophrenia group. Reduced hippocampal subfield volumes observed in both schizophrenia and ARMS groups may represent a common biotype associated with psychosis vulnerability. Volumetric changes of the left hippocampal tail may also suggest ongoing atrophy after the onset of schizophrenia.

Evaluation of Candidal Carriage Among Smokers and Non-Smokers

Objectives: To determine the Candidal carriage among smokers and non-smokers and with different intra-oral sites including examination of various biotypes of Candida. Study design and setting: Cross-sectional based study conducted at Dr. Ishrat ul Ebad Khan Institute of Oral Health Sciences and Dow International Dental College, Karachi, from May 2017 till April 2018. Methodology: Comprised 100 patients (50 smokers and 50 nonsmokers) between 20 and 60 years of age. The collection was performed through sterile cotton swab to evaluate oral Candidal carriage and the colonizing Candida species using Sabouraud Dextrose Agar (SDA) and API20C AUX (BIOMERIEUX). Data was analyzed Spss version 20. Results: A total of 100 participants (50 smokers and 50 non-smokers) were evaluated for candidal carriage. The common age group was 20-30 years in both the groups, without significant difference (p-value 0.79). Frequency of candidal carriage was comparable among smokers 14 (28.0%) to non-smokers 10 (20.0%), with a statistically insignificant p-value 0.35. Based on various biotypes among smokers and non-smokers, Candida albicans was 9(18%) and 7(14%), Candida glabrata was 4(8%) and 2(4%); and Candida tropicallis was 1(2%) each for both smokers and non smokers. Dorsum of tongue harbored all prevalent biotypes i.e. Candida albicans, Candida glabrata and Candida tropicalis as statistically significant among smokers (p-value 0.04). Conclusion: Candidal carriage was comparable among smokers and non-smokers. Candida albicans and Candida glabrata were the common biotypes predominantly among smokers

Microbiological Characterization and Antibiotic Susceptibility Pattern of Haemophilus Influenzae Isolates from a Tertiary Care Centre in South India

Haemophilus are fastidious Gram negative bacilli, which require factor X (hemin), factor V (NAD), or both for their growth. Haemophilus influenzae is the type species, and is considered to be the most pathogenic. They are associated with many invasive infections including meningitis, epiglottitis, pneumonia, and otitis media. Serotype b is most commonly associated with infections. Haemophilus species isolated from patients in a tertiary care centre in South India were studied. Identification, serotyping and biotyping were done and antibiotic susceptibility test was performed. The incidence of H. influenzae infections in our study was 65.3 cases/100,000 persons. Serotype b was the most common (66.67%), followed by non typeable H.influenzae (NTHi) (25%). Most isolates from adults were type b, while all isolates from pediatric population were non typeable. The most common biotype was type II, followed by type I and type III. Three of 24 isolates were β lactamase producers (12.5%). One isolate was β lactamase negative Ampicillin resistant (BLNAR). Resistance to ampicillin was 16.67%. Resistance to cephalosporins and fluoroquinolones was low (4-10%). Co-trimoxazole resistance was found to be very high (75%). All isolates were susceptible to azithromycin, tetracycline, chloramphenicol and meropenem. No isolates of H.influenzae type b were obtained from the paediatric population which may be due to the introduction of Hib vaccine. The increase in resistance to commonly used antibiotics is worrisome, especially penicillins and co-trimoxazole. Use of co-trimoxazole in empirical therapy of upper and lower respiratory tract infections has a high chance of failure in the current scenario.

Investigation of six plasmid-mediated quinolone resistance genes among clinical isolates of pseudomonas: a genotypic study in Saudi Arabia.

Background: Quinolones are among the most effective antibiotics against Pseudomonas spp. Several chromosomal and/or plasmid-mediated quinolone-resistance mechanisms have been found in Pseudomonas. Plasmid-mediated quinolone-resistance (PMQR) is mediated by quinolone-resistance (QNR) proteins, modifying enzymes or efflux pumps. Only a few previous studies examined the prevalence of quinolone-resistance in the Kingdom of Saudi Arabia (KSA) and showed it is increasing. Mechanisms of quinolone-resistance among Pseudomonas spp. in the KSA; examined herein; have not been extensively studied.Methods: Ninety-two Pseudomonas isolates were collected and their resistance to seven different types of quinolones was determined by the microbroth dilution method. PMQR mechanisms were examined using a PCR screen to identify six PMQR genes including qnrA, qnrB, qnrD, qnrS, aac(6´)-Ib-cr, and qepA. Clonal relatedness of the quinolone-resistant isolates was determined by ERIC-PCR.Results: Of the isolates, 42.4% (39/92) were resistant to 1-7 of the tested quinolones. Gemifloxacin resistance was the lowest (28.3%) while resistance to the other six quinolones were ≥ 35%. The most common biotype among the 39 quinolone-resistant isolates was resistance to the seven tested quinolones (26/39; 66.7%). qnrD, qnrS, and aac(6´)-Ib-cr were found in 31 (79.5%), 31 (79.5%) and 28 (71.8%) of the 39 isolates, respectively, and all three genes together were found in 22 of the 39 isolates (56.4%). qnrA, qnrB, and qepA were not detected in any of the isolates and two isolates did not harbor any of the six tested genes. The isolates showed 38 different ERIC profiles and only two isolates (Pa16 and Pa17) had an identical profile.Conclusion: This is the first description of PMQR mechanisms among clinical Pseudomonas isolates from the KSA, which appears to be mainly mediated by qnrD, qnrS, and aac(6´)-Ib-cr.

Biotipos y susceptibilidad antimicrobiana de S. mutans en niños con y sin caries dental

Objetivos: investigar los biotipos de S. mutans aislados de niños con y sin caries dentaly determinar su susceptibilidad antimicrobiana. Métodos: este estudio observacionaldescriptivo incluyó 206 niños entre los 3 y 5 años de dos preescolares en Bogotá, D.C., Colombia. Después de su aislamiento en agar Mitis Salivarius Bacitracina, lascepas S. mutans se identificaron por pruebas bioquímicas y se biotipificaron por elsistema api-ZYM. En todos los aislamientos se determinó por el método de diluciónenvagar la concentración inhibitoria mínima (CIM) de Penicilina, Amoxicilina, Cefazolina, Eritromicina, Clindamicina, Imipenem, Vancomicina y Teicoplanina.Resultados: Se encontró S. mutans en 30 de los 79 niños sin caries dental (38%) y en56 de los 127 niños con caries (44,1%). Los niños con caries presentaron un recuentosuperior de S. mutans en comparación con los niños sin caries (p < 0,05). En totalse identificaron 121 cepas de S. mutans en los 86 niños: 43 cepas en los 30 niños sincaries dental y 78 en los 56 niños con caries dental. Las 121 cepas fueron agrupadasen 38 biotipos: 24 en el grupo de caries y 14 en el grupo sin caries. En el grupo decaries los biotipos más frecuentes fueron el XV, XI, XII y XVII, respectivamente,con 26, 12, 11 y 4 cepas y en el grupo sin caries los biotipos más frecuentes fueronel XXVI, XX y XXXVI, respectivamente, con 14, 8 y 7 cepas. Todos los biotipos

Akdeniz Bölgesi’nden toplanan Bemisia tabaci (Gennadius) (Hemiptera:Aleyrodidae) popülasyonlarının biyotiplerinin belirlenmesi

Common biotypes of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) at agricultural production areas of Mediterranean Region were aimed to determine in this project. For this purpose, whitefly samples were collected from production areas at the different districts of Antalya, Adana, Mersin and Hatay provinces at Mediterranean Region in 2009-2012. B and Q biotypes were determined by using SCAR-PCR method. Two population out of 27 populations were detected as Q biotypes, others B biotype. Therefore, it was concluded that B and Q biotypes located at Mediterranean Region prefer different habitats in the region. While B biotype is especially common in vegetable production areas, Q biotype is widespread on the biennial plants.

Estudio de la forma y tamaño de los incisivos superiores de los estudiantes de odontología según el principio embriogenético de Gerber

El objetivo de éste trabajo fue encontrar el patrón mas prevalente acorde con el principio embriogénico de Gerber. Se trabajó con una muestra de 100 estudiantes de odontología de la UNMSM de ambos sexos entre 18 y 27 años, sin alteraciones en el sector anterosuperior, a los que se les realizó un examen clínico, análisis fotográfico y modelos de estudio. El análisis estadístico se realizó con el programa SPSS 19. Se observó comol biotipo mas frecuente (según Mayoral) el braquifacial (50 %), seguido del mesofacial (44 %) y dólicofacial (6 %), se encontró concordancia con el segundo y tercer postulado de Gerber (2do postulado: proporción de los incisivos centrales y laterales similar a la proporción entre la base y la raíz nasal; y 3er postulado: relación entre la angulación del plano incisal con la línea base nasal -índice alar o índice de Gerber-); pero no se encontró concordancia con el primero postulado (1er postulado: el ancho de los cuatro incisivos correspondería a la longitud del ancho de la base nasal). Se halló el diámetro mesiodistal promedio del incisisvo central 8.62±0.52 IC 95% 8.55-8.69, incisivo lateral 7.08±0.55 IC 95% 7.00-7.16 y de los cuatro incisivos en conjunto (31.07 a 31.75 mm IC 95%), ésta última medida fue la no coincidente con la base nasal (37.32 a 38.7 mm IC 95 %), la cual siempre fue mayor que el diámetro de los incisivos, lo que significa que no puede ser un patrón de referencia para la población peruana para aspectos estéticos reahabilitadores.

タバココナジラミバイオタイプNauruに対する各種薬剤の殺虫効果

The effect of pesticides on the Nauru biotype, a common biotype of Bemisia tabaci in the Ryukyu Islands, was compared with that on the B biotype under laboratory conditions. Twenty-four commercial agrochemicals were tested on adults, third instar larvae, and eggs. Overall, the majority of the pesticides tested were effective (>70% mortality) for Nauru, but not for the B biotype. Fourteen insecticides were effective for all stages of the Nauru biotype, while only two (pyridaben and emamectine benzoate) were effective for all stages of the B biotype. The effects of synthetic pyrethroid, imidacloprid, and some acaricides were clearly greater in the Nauru biotype than in the B biotype. The results suggest that the Nauru biotype is a less important pest than the B biotype because of the greater susceptibility to insecticides of the former.

琉球諸島におけるタバココナジラミバイオタイプの野生寄主

Determination of wild host plants as possible sources of pest insects is important for integrated crop management in cultivated areas. We first clarified biotypes of the whitefly, Bemisia tabaci, infesting non-crop plants (36 species in 14 families) throughout the Ryukyu Islands, which are subtropical areas in Japan. The B biotype, the most common biotype on crop plants in this area, was found on 32 non-crop plant species (in 13 families), and frequently infested asteraceous and euphorbiaceous weeds; therefore, control of these weeds is important for integrated management of the B biotype in the Ryukyu Islands. The Nauru biotype had a narrower host range, and was found on 13 plant species (in 6 families). The Q biotype was found only once on a Solanum weed. One biotype belonging to the genetic group ‘China’ was identified from two plant species growing on the seashore.

The first report of isolation and molecular characterisation of Brucella melitensis Rev-1 vaccine strain from an aborted sheep fetus in Turkey

The aim of this study was to evaluate a RAPD-PCR for the detection of B. melitensis Rev-1 vaccine strain. In addition, our objective was to isolate, identify and genetically characterize B. melitensis strains from aborted sheep fetuses by PCR, RAPD-PCR and PCR-RFLP methods. A total of 86 aborted sheep fetuses obtained from different herds ( n = 86) in lambing season of 2007–2008 were evaluated. Twelve B. melitensis strains , which isolated from aborted sheep fetuses ( n = 12) from same region between 2006 and 2007 years were also added in this study for biotyping. Brucella strains were isolated from 24 (28%) out of 86 aborted sheep fetus samples. All Brucella strains were identified as B. melitensis by biochemical tests and PCR. Of the 36 B. melitensis isolates, 3, 32 and 1 were identified as biotype 1, biotype 3 and B. melitensis Rev-1 vaccine strain, respectively. Field isolated B. melitensis Rev-1 vaccine strain was confirmed by PCR-RFLP. Nine of 36 B. melitensis isolates were detected for being atypical since they were susceptible to penicillin or thionin and basic fuchsin. DNA fingerprints of field isolates and B. melitensis Rev-1 vaccine strain were obtained by RAPD-PCR method and dendograms were created by UPGMA and NJ. Strains were separated similarly 14 subgroups in both dendograms. 36 B. melitensis isolates from Konya region were detected that they had not from the same source. Atypical strains that located in different subgroups have different clonal origins. Levels of genetic similarity between reference strains and field isolates were 50.0–99.9%. That was 88.9% between reference vaccine strain B. melitensis Rev-1 and field isolated B. melitensis Rev-1. It was also detected that B. melitensis Rev-1 vaccine strain cannot be identified by the method RAPD-PCR alone, while isolates in located the same main group with B. melitensis Rev-1 can be suspected for being the vaccine strain. In conclusion, B. melitensis strains isolated in Konya region were found to be from different sources by RAPD-PCR. B. melitensis biotype 3 was the most common biotype. B. melitensis Rev-1 vaccine strain was isolated from aborted fetus in Turkey for the first time. PCR-RFLP appear valuable tool for epidemiological studies on B. melitensis Rev-1 vaccine strain. RAPD-PCR method was concluded as for being an easy to use and interpretate. This is recommended for future studies on epidemiology of Brucellosis.

Prevalence of Campylobacter species in apparently healthy goats in Sokoto state (Northwestern) Nigeria

A total of 1312 rectal swabs (feacal) samples were collected from apparently healthy goats across Sokoto state and processed for Campylobacter organisms. 264 (20.1%) of the samples were positive and yielded 272 Campylobacter species.Campylobacter species isolated in this study were Campylobacter jejuni 169(62.1%),Campylobacter coli 58(21.3%), Campylobacter lari 24(8.8%), Campylobacter upsaliensis 13(4.8%) and Campylobacter sputorum 8(3.0%). Biotyping of the isolates indicated that C. jejuni biotype I (52.6%) and C. coli biotype II (82.8%) were the most common biotypes while all the C. lari isolates were biotype I. The isolation of Campylobacter organisms and the identification of C. jejuni biotype I and C. colibiotype II from goats in this study is a clear indication of the presence ofCampylobacter in goats in Sokoto state. Campylobacter organisms must be considered as potential agent of enteritis and abortion in goats as well as a serious public health problem. Key words: Biotypes, Campylobacter, Campylobacter jejuni, Campylobacter coli,Nigeria, prevalence, goats.

QPCR quantification and genetic characterization ofClostridium perfringenspopulations in biosolids composted for 2 years

The ability of Clostridium perfringens to survive for a long time in the environment makes it a suitable indicator of faecal pollution, but its use as a routine indicator organism in biosolids and composted biosolids has not yet been adopted. This study was performed to improve our understanding of C. perfringens persistence in composted biosolids by monitoring its presence and studying its genetic diversity. A culture-independent TaqMan qPCR assay targeting the cpn60 gene was adapted to enumerate C. perfringens in composted biosolid samples varying in age from 1 to 24 months. The pathogen was detected in all compost samples under study, but no correlation between composting time and number of cpn60 copies was observed. Rep-PCR detected 14 different C. perfringens genotypes, all belonging to toxinotype A, which is the most common biotype found in human and animal gastrointestinal tracts. Composting did not significantly decrease the number of C. perfringens cells. High genetic diversity of C. perfringens isolates present in composted biosolids is reported for the first time. This study evaluated tools for surveillance of composting processes, source tracking and risk assessment of composted biosolids.

Biotypes of group A streptococci from patients with pharyngitis and soft tissue infections

This study determined the biotypes of group A streptococci (GAS) isolated from 66 pharyngeal and 62 skin and soft-tissue infections. Among all GAS isolates tested, the most common biotypes were 1 and 3, irrespective of the isolation source and the severity of clinical symptoms. However, compared with the pharyngeal group, a more heterogeneous distribution of biotypes was observed among the cutaneous group of isolates, including seven isolates that were non-typeable but had an identical biotype pattern, suggesting that they may represent a new biotype.

Variation among hexaploid Paspalum dilatatum Poir. regenerants from tissue culture

The common biotype of Paspalum dilatatum Poir. (dallisgrass) is a pentaploid obligate apomict and efforts to improve the grass have not been successful because of its asexual reproduction and irregular meiosis. An apomictic hexaploid biotype, known as Uruguayan dallisgrass, is a new source of genetic variation that may be useful in improving dallisgrass. As with common dallisgrass, improvement of this biotype via conventional breeding methods is difficult because of its apomictic reproduction. However, the use of tissue culture to produce somaclonal variation in the Uruguayan biotype has not been reported, and may offer a means for improving the species. The objectives of this research were to: (i) regenerate plants of Uruguayan dallisgrass through tissue culture, (ii) screen the regenerants for useful agronomic variation and evaluate their forage potential and nutritive value, and (iii) determine the genetic relatedness of the regenerants and their explant sources. In total, 178 plants, selected from 2372 regenerants in preliminary screening, were evaluated for forage nutritive value. Thirty-seven of these were planted into replicated field plot trials at two locations. None of these regenerants were superior to the Uruguayan biotype for forage nutritive value. However, two regenerants, 3440 and 3441, produced more forage than either the Uruguayan or common biotypes in evaluation tests for 3 years at one of the two locations. Data from AFLP analyses indicate genetic variation between two of the Uruguayan accessions and these two regenerants. This variation could account for the differences in forage yield between 3440 and 3441 and the Uruguayan accessions.

A Common Ragweed (Ambrosia artemisiifolia) Biotype in Southwestern Québec Resistant to Linuron

The degree of resistance to linuron of a common ragweed biotype was investigated. Suspected linuron-resistant plants collected from a carrot field near Sherrington, Québec, were subjected to increasing rates of linuron under glasshouse conditions. Resistance to linuron of the common ragweed biotype was suspected because 33% of plants survived to reproduction after they were sprayed at a rate of 4.5 kg ai/ha, two times the dose rate recommended for linuron in carrots, and also because 3% of plants survived to reproduction after they were sprayed at a rate of 22.5 kg ai/ ha, 10 times the recommended dose. Susceptible plants collected from a field with no prior history of linuron use were all killed when sprayed at the lowest dose rate recommended, 1.125 kg ai/ha. The herbicide-resistance ratio was 29.0 for linuron, and for cross-resistance to atrazine, the ratio was 1.3, indicating that these plants exhibit greater resistance to linuron than to atrazine.

Common Antimicrobial Resistance Patterns, Biotypes and Serotypes Found among Pseudomonas aeruginosa Isolates from Patient's Stools and Drinking Water Sources in Jordan

Pseudomonas aeruginosa was isolated in low rates from stool specimens of outpatients and inpatients (7% versus 12%) but in higher rates from chlorinated and nonchlorinated water sources (15% versus 44%), respectively in Jordan. The same biotype was recognized among 90% of P. aeruginosa isolates from patient's stools and water sources using specific biochemical profiles. Three serogroups belonging to 01, 06 and 011 accounted for the majority of these isolates in water (66%) and stools (78%), respectively. All P. aeruginosa isolates from water were highly susceptible (87%-100%) to piperacillin-tazobactam, amikacin, gentamicin, imipenem, aztreonam, ceftazidime and ciprofloxacin, whereas the isolates from stool were slightly less susceptible (81%-98%) to these antimicrobials. P. aeruginosa isolates from water and stool sources were almost equally highly resistant to tetracycline (86%-89%) and carbenicillin (88%-89%), respectively. One common small plasmid (15.4 kb) was detected in 14/25 (56%) of multidrug-resistant P. aeruginosa isolates from both water and stool. This study demonstrates certain common epidemiological characteristics including antimicrobial resistance pattern, biotypes and serotypes among P. aeruginosa isolates from patient's stools and drinking water sources in Jordan.

Forage Yield, Nutritive Value, and Grazing Tolerance of Dallisgrass Biotypes

Common dallisgrass (Paspalum dilatatum Poir.) is an important forage grass in many subtropical regions including the southeastern USA. The term dallisgrass is synonymous with the common biotype. There are other biotypes of this species but little is known about their forage potential. This study was initiated to evaluate accessions of five dallisgrass biotypes (common, prostrate, Torres, Uruguaiana, and Uruguayan) and ‘Pensacola’ bahiagrass (P. notatum var. saurae Parodi) for forage yield, nutritive value, and persistence in southern Louisiana and southeastern Texas, and to determine the response and persistence of the superior biotypes under grazing. Three years of clipping data were collected at Baton Rouge, LA, and College Station, TX. Most of the Uruguayan accessions were equal or superior to common dallisgrass for yield and nutritive value and all had superior stand persistence. The Torres and Uruguaiana biotypes did not survive after the first harvest season. Forage production and persistence of prostrate dallisgrass and Pensacola bahiagrass were better than expected. Six superior accessions of the Uruguayan biotype and common dallisgrass were evaluated under grazing for 3 yr at Jeanerette, LA. After 2 yr of rotational stocking, an average of 90% of the Uruguayan and only 53% of the common dallisgrass plants survived. This was followed by one season of continuous stocking and the average plant survival decreased to 75% for the Uruguayan accessions and 33% for common. Because the yield and persistence of the Uruguayan biotype was consistently superior to that of common, Uruguayan dallisgrass could provide livestock producers in the southeastern USA with a viable alternative to common dallisgrass.

Clinical and microbiological features of Haemophilus influenzae vulvovaginitis in young girls

Aims: To define the clinical and microbiological features of vulvovaginitis in prepubertal girls whose genital swabs yielded Haemophilus influenzae. Methods: Laboratory based study and retrospective collection of clinical data from...

RAPD analysis reveals genetic variability among sexual and Apomictic Paspalum dilatatum poiret biotypes.

Paspalum dilatatum is a valuable forage grass in the subtropics. This species consists of several sexual (tetraploid) and apomict (penta- and hexaploid) biotypes. It has been proposed that the presence of a genome of unknown origin, the X genome, is responsible for apomixis in penta- and hexaploid biotypes. Here we evaluated the utility of random amplified polymorphic DNA (RAPD) markers for discriminating sexual and apomictic P. dilatatum biotypes. DNA samples from nine accessions, including P. intermedium, P. juergensii, and P. dilatatum (ssp. flavescens, and the common and Uruguayan biotypes) were analyzed with 86 RAPD primers. Three hundred sixty-two fragments were scored and genetic similarity estimates revealed that the penta- and hexaploid biotypes were highly similar (S(D) > or = 0.913). Forty RAPDs were unique to the penta- and hexaploid biotypes. Overall RAPD markers were useful for assessing genetic variation among closely related P. dilatatum genotypes as well as generating putative X genome markers.