bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal Variation in the Phytoplanktonic Community, Seston and Environmental Variables During a 2‐Year Period and Oyster Growth at Two Mariculture Sites, Southern Chile
Authors: Toro Jorge E. , Paredes Pamela I. , Villagra Darío J. , Senn Carolina M.
Published: March 2003

Phytoplankton and its relationships with physical and chemical variables were analysed over a 2‐year period in Hueihue and Linao Bays (southern Chile). Samples were collected on a monthly basis from May 1991 to May 1993. The growth rate of a single stock of hatchery‐produced oysters (Ostrea chilensis) distributed between these two bays was also monitored monthly. The growth rate of oysters maintained at Linao Bay (site associated with a fish farm) was significantly higher, at every depth, compared with the oysters maintained at Hueihue Bay. Temperature and salinity values and their annual fluctuations were similar at both locations, presenting higher variations at the surface (1 m) due to the influence of air temperature and local precipitation than at depth. However, significant differences in phytoplankton abundance and composition were found between the two locations. The phytoplankton community was characterized by high biomass values during spring and summer, the dominance of diatoms and an inverse relationship between temperature and species diversity. However, phytoplankton cell abundance, biovolume and chlorophyll a concentration were significantly higher at Linao at every depth sampled. Cell abundance ranged between 4.49 × 104 and 7.45 × 106 cells · l−1 in Hueihue and between 6.48 × 104 and 8.71 × 106 cells ·1−1 in Linao. The influence of temperature on chlorophyll a concentration was significant except at 8 m at both locations. The instantaneous oyster growth rate was found to be positively correlated with temperature, chlorophyll a concentration and particulate organic matter at both locations. A significant negative relationship between oyster growth and amount of particulate inorganic matter was found; this confirms the important role played by seston composition in oyster growth. The demonstration of variation in oyster growth rate associated with differences in food availability between the two locations provides insight into the ecological role played by fish farms in southern Chile. The results suggest a strong link between food availability and oyster growth.
Reproduction of Donax venustus Poli 1795, Donax semistriatus Poli 1795 and Intermediate Morphotypes (Bivalvia: Donacidae) in the Littoral of Málaga (Southern Spain)
Authors: Tirado Cristina , Salas Carmen
Published: March 2003

The reproduction and sexual cycles of Donax venustus Poli 1795, Donax semistriatus Poli 1795, and individuals with intermediate shell morphotypes were studied in the littoral of Málaga (Southern Spain) from February 1990 to January 1991, using histology and analysing the changes in flesh dry weight. The littoral of Málaga has mild seawater temperatures and several upwellings with high levels of chlorophyll a. Due to these environmental conditions, the reproductive periods of these bivalve species are very extensive, from February to November. The histological study shows asynchronous sexual cycles, with continuous but partial individual spawnings from April to November in about 50% of the D. semistriatus population, and percentages higher than 40% of the sample in most months for D. venustus. An important decrease in the ratio flesh dry weight/length3 was noted from June to August in the three populations; this is apparently related with peaks of spawning. Based on the macroscopic observation of the gonads, on the flesh dry weight study and on histological data, the sexual cycle of the intermediate morphotypes is simultaneous and similar throughout the year with those of D. venustus and D. semistriatus.
Population Density, Distribution and Consumption Rates of Three Corallivores at Cabo Pulmo Reef, Gulf of California, Mexico
Authors: Reyes‐Bonilla Héctor , Calderon‐Aguilera Luis Eduardo
Published: March 2003

Abstract. The influence of corallivores on coral community structure of eastern Pacific reefs has been considered less important then that of abiotic oceanographic factors. The data that support this assumption, however, are only available for Central American reefs. To assess the role of predation on hermatypic corals in a different regional reef environment, the abundance, spatial distribution and consumption rate of three corallivores: the echinoid Eucidaris thouarsii (Valenciennes), the asteroid Acanthaster planci (Linnaeus) and the teleostean fish Arothron meleagris (Bloch & Schneider), were estimated at Cabo Pulmo reef, Gulf of California, México (23°25′ N, 109°25′ W). Statistically, the abundances of the species did not change in any sections of the reef (mean values: E. thouarsii, 0.17 indiv. · m−2; A. planci, 1.9 indiv. · m−2; A. meleagris, 39 indiv. · ha−1). The average daily individual consumption rates of coral were calculated at 1.83 g CaCO3· m−2 for E. thouarsii, 118.4 cm2 for A. planci, and 16.38 g CaCO3· m−2 for A. meleagris, and were lower than those reported for Central American reefs. Considering the mean estimated carbonate production (7.9 kg CaCO3· m−2· a−1), corallivores eliminate less than 4% of the coral standing stock of Cabo Pulmo reef. The low corallivore population density and consumption rates, together with high local coral cover, indicate that corallivores are not key factors determining scleractinian abundance in this marginal reef.
The Burrows of Callianassa tyrrhena (Petagna 1792) (Decapoda: Thalassinidea)
Authors: Dworschak Peter C.
Published: March 2003

Abstract. Burrows of the thalassinidean shrimp Callianassa tyrrhena were investigated by in situ resin casting on two tidal flats in the Adriatic Sea.

The burrow openings are characterised on the surface by simple holes or funnels. The number of openings per burrow ranges from 2 to 4. Burrows consist of a single or multiple shallow U with thin shafts (2 – 11 mm diameter) leading to the surface and a main central spiral shaft consisting of a series of enlarged chambers (with an elliptical cross‐section of up to 10 × 20 mm) linked by other segments (with a circular cross‐section of 5 to 13 mm in diameter). Several chambers filled with seagrass debris branch off. Burrows reach a depth of down to 62 cm and have a volume of up to 300 cm3.

Additional information is provided on the redox properties of the burrow wall, and on bacterial numbers and biomass along the burrow wall and in the debris chambers. The morphology of the burrows and the impact of the imported organic matter on the deeper sediment layers is discussed.
Ultrastructure of Gnathostomaria lutheri Ax (Gnathostomulida: Scleroperalia).I. An Hypothesis About the Origin of ­Micropodia in Scleroperalian Sperm
Authors: Sterrer Wolfgang , Salvenmoser Willi , Rieger Reinhard M.
Published: March 2003

Abstract. Initially described as an aberrant taxon of turbellarian flatworms, the Gnathostomulida were recognized as a distinct phylum by Rupert Riedl already in 1969. Yet these microscopic, non‐segmented marine worms remain organisms of enigmatic phylogenetic affiliation, and although they are often the dominant invertebrate taxon in detritus‐rich, oxygen‐poor sands, our knowledge of their biology is still very scanty. About 90 gnathostomulid species are known to date; they are grouped in two orders, one with two suborders. Sperm structure, often a useful instrument for clarifying evolutionary pathways in metazoan taxa, differs so widely between the orders and suborders that sperm phylogeny within the Gnathostomulida also remains uncertain. We here report on the ultrastructural features of a peculiar type of sperm, the aflagellar “megasperm” of Gnathostomaria lutheri, and discuss new and older interpretations of sperm cytology of the taxon.
Epidemiology of dermatomycoses of humans in Central Poland. Part IV. Onychomycosis due to dermatophytes
Authors: Lupa S. , Seneczko F. , Jeske J. , Głowacka Anna , Ochęcka‐Szymańska Aldona
Published: March 2003

The total number of dermatophytoses (7393) included 1567 (21.2%) cases of onychomycosis. Etiological factors in descending order were: Trichophyton rubrum (58.8%), Trichophyton mentagrophytes var. granulosum (26.2%), T. mentagrophytes var. quinckeanum, T. mentagrophytes var. interdigitale (5.1%), Trichophyton tonsurans (4.1%), Trichophyton violaceum (1.5%), Trichophyton spec. (1.1%). An increase in the incidence was noted between 1994 and 1996. At present, onychomycosis is third by incidence among all clinical forms of dermatophyte infections of skin and skin appendages in the Łódź region.
Candida albicans clinical isolates inactivated by formalin with different adherence to buccal epithelial cells induce proinflammatory and regulatory cytokines in human peripheral blood mononuclear cells
Authors: Kunze R. , Schütz B. , Schrödl W. , Bernhardt Hannelore
Published: March 2003

Besides the activation of phagocytes, the release of cytokines is the most important immunological defence mechanism of an organism against infection with Candida albicans. On the other hand cytokines induced in the organism by the yeast itself are able to modulate the immune responses of the host. We investigated whether eight clinically isolated strains of C. albicans inactivated by formalin as well as a laboratory strain were able to induce proinflammatory and regulatory cytokines in peripheral blood mononuclear cells (PBMC) of four different donors. Under our assay conditions the yeast strains induced the cytokines interleukin‐1β (IL‐1β), interferon‐γ (IFN‐γ) and interleukin‐10 (IL‐10) in PBMC to varying extents, but not the cytokine interleukin‐4 (IL‐4). We observed a difference in the reaction of the individual donors to the stimulus C. albicans but on the other hand the extent of the cytokine signal seemed to be dependent on the yeast strain as well. No correlation was found between the ability of the individual C. albicans strains to induce cytokines in PBMC and their ability to adhere to buccal epithelial cells. Determination of the cytokine induction potential of C. albicans strains possibly may contribute to the detection of new virulence factors of this yeast.
Case Report. Mixed systemic mycosis with fatal outcome in a patient with acute myeloblastic leukaemia
Authors: Binder Claudia , Rüchel
Published: March 2003

Fungal infections represent an increasing problem in immunocompromised patients. The majority of cases are caused by one single fungal pathogen and infections with more than one fungus are very rare. Here we describe a case of combined infection with Aspergillus and a zygomycete species, involving the lungs, spleen and the brain and leading to fatal outcome in spite of early antimycotic therapy.
Antibodies to antigens of Histoplasma, Blastomyces and Candida in HIV patients and carriers in Nigeria
Authors: Muotoe‐Okafor  , Gugnani  , Gugnani  , Okafor
Published: March 2003

Serum samples from 60 subjects with confirmed HIV‐1 infection including 28 AIDS patients and 32 carriers were examined by immunodiffusion for precipitating antibodies to antigens of Histoplasma, Blastomyces and Candida. Seven of the subjects, four patients and three carriers, showed antibodies to histoplasmin prepared from mycelial cultural filtrate of Histoplasma capsulatum var. capsulatum and H. capsulatum var. duboisii although without any clinical signs of classical or African histoplasmosis. Another eight subjects comprising five patients and three carriers demonstrated antibodies to yeast cell antigen of Candida albicans; three of the patients had oral lesions clinically suggestive of Candida infection. None of the serum samples revealed antibodies to ‘‘A’’ antigen (yeast cell antigen) of Blastomyces dermatitidis.
Oral yeasts and coliforms in HIV‐infected individuals in Hong Kong
Authors: Tsang C. S. P. , Samaranayake L. P.
Published: March 2003

The objective was to determine the oral carriage patterns of yeasts and coliforms and their relationships, if any, with age, risk group, CDC classification, CD4+ count and medications in a predominantly Chinese, HIV‐infected cohort in Hong Kong. A prospective longitudinal study was carried out over a 12‐month period, of 32 predominantly Chinese male HIV‐infected cohort in a hospital setting in Hong Kong. Oral carriage rates were determined by the concentrated rinse culture method and correlated with other clinical parameters using regression analysis. A total of 73 oral rinse samples were collected and the weighted mean carriage rates of oral yeasts and coliforms were 54.8% and 28.8%, respectively. The most common yeast and the Enterobacteriaceae isolated were Candida albicans and Enterobacter cloacae, respectively. An increased carriage rate of yeasts was associated with zidovudine usage and Centres for Disease Control (CDC) stage IV of the HIV infection whereas the opposite was associated with the usage of antiparasitics and multivitamins. Although the oral carriage rate of coliforms was significantly lower in individuals taking antibacterials and multivitamins, it was not significantly influenced by age, CD4+ lymphocyte count and the intake of antivirals, antifungals or folates. These data imply that oral yeast carriage in HIV infection is related to the severity of the disease as opposed to oral coliform carriage which appears to be unusually transient in the study cohort.
Transmission of Trichosporon asahii oesophagitis by a contaminated endoscope
Authors: Lo Passo C. , Pernice I. , Celeste A. , Perdichizzi G. , Todaro‐Luck F.
Published: March 2003

Summary.  Two cases of oesophageal trichosporonosis due to a suspected nosocomial infection are reported. Both the patients were immunocompetent and had undergone an endoscopic examination on the same day. Six strains of Trichosporon were isolated: three strains from the oesophageal biopsy of the first patient, one strain from the endoscopic forceps, one from the air in the endoscopy room, and one from the oesophageal biopsy of the second patient. The nosocomial nature of the infection and the role of the endoscopic forceps in transporting the micro‐organism was suspected, but the morphology and physiology of the isolated strains did not confirm such hypothesis. To elucidate the nature of the infection and the genetic similarities of the strains isolated, all strains were typed with RFLPs of the rDNA fragment and with RAPD. The results of RAPD using primer (GTG)5 (GACA)4, M13 core sequence, and the 15‐mer oligonucleotide GAGGGTGGXGGXTCT indicated the molecular identity of three strains supporting the hypothesis concerning a transport of the aetiological agent from the first patient to the second and that the carrier was the forceps of the endoscopic device.
Antifungal activity of Crotalus durissus cumanensis venom
Authors: Magaldi S. , Girón M. E. , Aguilar I. , Rodriguez‐Acosta A.
Published: March 2003

Summary. The susceptibility to Crotalus venom of 14 yeast and 10 mould fungal isolates was assessed. This venom was tested in a standardized well diffusion test, using 400 µg/20 µl well. The percentage of susceptibility to yeast isolates was 78.6% (> 8 mm); that for filamentous isolates was 50% (> 8 mm).
Animal models of aspergillosis – also useful for vaccination strategies?
Authors: Schmidt A.
Published: March 2003

Summary. The attempt to establish vaccination strategies against infections caused by Aspergillus fumigatus seems to be questionable. Invasive aspergilloses are opportunistic diseases of the immunocompromised host and only a passive immunization with immunoglobulins could be taken into consideration. Until now there have been no preclinical and/or clinical data available concerning the efficacy of specific immunoglobulins; animal experiments could offer an approach for the preclinical assessment of this topic. Generally, A. fumigatus is an opportunistic pathogen. Birds show a relatively high susceptibility to infections caused by A. fumigatus. In laboratory animal species, rabbits seem to have the highest susceptibility followed by mice, rats and guinea‐pigs. Mice are easy to handle in all‐day laboratory use, and infections are mostly established by the intravenous, intranasal or intraperitoneal route. The main target organs of infection are the kidneys by all three infection routes. Forty clinical isolates of A. fumigatus tested showed a comparable virulence in systemic infections in the intravenously infected mouse model. By using histopathological techniques, we also observed infectious lesions within the central nervous system in all cases. Only A. fumigatus strains lacking green pigmentation showed a significantly lower virulence. Histopathological examinations are of great benefit in the study of these animal models as they give detailed information about the infectious process. Measuring colony‐forming units in tissues is only of minor use in prediction as it cannot discriminate between infective tissue lesions and cavity‐infections/persistence, e.g. in the kidney pelvis. Quantitative methods for measuring fungal organ burdens, e.g. by chitin–enzyme‐linked immunosorbent assays, have also been described and offer an alternative towards solely measuring colony‐forming units in tissues.
Adherence of Candida strains isolated from the human gastrointestinal tract
Authors: Biasoli M. Susana , Tosello M. Elena , Magaró H. María
Published: March 2003

Summary.  The adherence of different Candida strains isolated from the human gastrointestinal tract was studied. The 23 Candida strains isolated from faeces were C. albicans (12), C. glabrata (2), C. krusei (2), C. parapsilosis (2), C. tropicalis (2), C. colliculosa (1), C. kefyr (1) and C. lusitaniae (1). Buccal epithelial cells from different healthy donors were used. Adherence values were maximal for C. albicans and minimal for C. krusei. A relation exists between yeast adherence capacity and the ability to colonize mucosal surfaces.
Fungal flora of human toe webs
Authors: Oyeka C. A. , Ugwu L. O.
Published: March 2003

Summary.  A total of 100 young adults (67 males and 33 females) participated in the study. Clinical evaluation showed that only 10 of the volunteers showed some scaling, fissuring and peeling of the toe webs. Four of these complained of occasional itching. Fourteen different genera of fungi were recovered from 78 of the 100 youths screened. Yeasts were recovered from 21 (27%) of the positive cases, nondermatophytes from 38 (49%) and dermatophytes from 19 (24%). Microsporum gypseum was the most commonly recovered dermatophyte. Rhizopus stolonifer and Trichosporon cutanueum were the most frequently recovered nondermatophytic mould and yeast, respectively. More males (62.8%) harboured these organisms than females (37.2%). The study further showed that human toe webs that are apparently healthy harbour a variety of fungi, that may be potential pathogens.
Case report. Isolation of Cladosporium cladosporioides from cerebrospinal fluid
Authors: Kantarcioǧlu A. S. , Yücel A. , de Hoog G. S.
Published: March 2003

Summary.  Cladosporium cladosporioides was isolated from three subsequent cerebrospinal fluid specimens and from a brain biopsy specimen of a human patient. Susceptibility testing of the isolate was performed against seven antifungal agents.
Total quality management in dermato‐mycology in Germany
Authors: Korting H. C.
Published: March 2003

Mycoses of the skin are extremely frequent. The clinical presentation often resembles the one of other frequent inflammatory skin diseases not caused by fungi. Adequate diagnostics are critical for the establishment of proper treatment. A total quality management system has been devised in Germany during the last 5 years. There are several guidelines addressing various aspects of the management of various types of disease as well as structure quality of laboratory diagnostics. Continuous medical education and so‐called ring trials are major aspects of implementation.
Variation in outcrossing rate and genetic structure on six cultivars of Vicia faba L. as affected by geographic location and year
Authors: Suso M. J. , Moreno M. T. , Melchinger A. E.
Published: March 2003

The present study was conducted to evaluate the importance of two environmental factors, year and geographic location, on the cultivar outcrossing rate and genetic structure of Vicia faba L. Under natural field conditions. Outcrossing rates were estimated for six cultivars using isozyme markers, the mixed mating model and the multilocus method. The genetic structure was described by Wright's fixation index and the inbreeding equilibrium coefficient. Faba bean outcrossing rate, as measured by multilocus estimates was relatively invariable among cultivars within locations. Our results suggest substantial variation in outcrossing rate associated with geographic location (Mediterranean subtropical and temperate climates enhancing the cross‐pollination). Year variation was far less important than geographic variation.
New sources for high resistance of tomato to the tomato spotted wilt virus from Lycopersicon peruvianum
Authors: Roselló S. , Soler S. , Díez M. J. , Rambla J. L. , Richarte C. , Nuez F.
Published: March 2003

Mechanical inoculation and transmission by thrips in a growth chamber were used in order to screen Lycopersicon peruvianumand Lycopersicon chilense germplasm for tomato spotted wilt virus (TSWV) resistance. Two highly aggressive Spanish TSWV isolates (HA‐931100 and T‐941117), having different restrictotypes were used. L. peruvianum accessions PI‐126935, PI‐126944, CIAPAN 16, PE‐18 and CIAPAN 17 showed high resistance to both isolates in mechanical and thrips transmission. Their resistance appears useful in breeding programmes.
Variation for aphid resistance and insecticidal acyl sugar expression among and within Lycopersicon pennellii‐derived inbred backcross lines of tomato and their F1 progeny
Authors: Hartman J. B. , St Clair D. A.
Published: March 2003

Five inbred backcross lines (IBL) were selected for higher relative expression of insecticidal acyl sugars (rank average) from an inbred backcross population derived from the cross Lycopersicon esculentum cultivar ‘Peto 84’×Lycopersicon pennellii accession LA716. These five BC2S5 IBLs were crossed in a partial diallel design (Method II), and their self and F1 progeny and three control cultivars were tested at two California field locations in 1996. Counts of potato aphids, Macrosiphum euphorbiae Thomas, on leaves, as a measure of plant infestation, revealed significant general combining ability (GCA) for lower aphid numbers with IBL44 and IBL59; the F1 hybrid IBL44 × IBL59 had significantly fewer aphids per leaflet than the susceptible cultivar ‘Alta’. GCA for acyl sugars was associated with IBL59 only. Of all the IBL and IBL × IBL F1 hybrids, only IBL59 produced significant levels of acyl sugars. Significant within IBL59 variation for acyl sugars was observed, but not for aphid resistance. Our results suggest that factors other than acyl sugars contributed to L. pennellii‐derived aphid resistance in IBL × IBL F1 hybrids and IBL that do not produce significant amounts of acyl sugars. IBL59 and IBL44 may be useful for breeding for aphid resistance in cultivated tomato.
Combining ability for beet armyworm, Spodoptera exigua, resistance and horticultural traits of selected Lycopersicon pennellii‐derived inbred backcross lines of tomato
Authors: Hartman J. B. , Clair D. A. St
Published: March 2003

Ten selected inbred backcross lines (IBL), from a Lycopersicon esculentum cv.‘Peto 84’×Lycopersicon pennellii IBL population, with resistance to beet armyworm (BAW), Spodoptera exigua, higher fruit mass and fruit yield, were crossed with eight elite cultivated L. esculentum inbred lines in a Design II mating design. Three elite inbreds were also crossed to ‘Peto 84′, the IBL recurrent parent, as a control for combining ability. Field plots of all resulting F1 progenies and control cultivars were inoculated with BAW eggs and evaluated for resistance to BAW, fruit mass, fruit yield, vine size and maturity at three field locations. Reductions in fruit damage by BAW were found in four of the 10 IBL F1 progenies. Significant male and female general combining ability (GCA) estimates for BAW resistance were observed, but significant specific combining ability for BAW resistance was not detected. The fruit mass of F1 hybrids was significantly lower than large‐fruited controls, but was not significantly different from elite inbred by ‘Peto 95’F1 hybrids. Selection based on inbred performance identified IBL with positive GCA for BAW resistance and yields in Design II hybrids. BAW resistance in the 09 selected IBL and IBL‐ derived F1 progeny was associated with two undesirable traits, later maturity and larger vine size. Index selection of IBL was more effective at identifying IBL with positive GCA for fruit mass and fruit yield than GCA for BAW resistance.
Inheritance of morphological traits of periwinkle mutants with modified contents and yields of leaf and root alkaloids
Authors: Kulkarni R. N. , Baskaran K. , Chandrashekara R. S. , Kumar S.
Published: March 2003

Periwinkle Catharanthus roseus is a medicinally important plant producing anticancer and antihypertension alkaloids. Two mutants, one dwarf and one semidwarf and both, with a high alkaloid content in the roots and one mutant with a wavy leaf margin and a high alkaloid content in its leaves were obtained after induced chemical mutagenesis with ethyl methane sulphonate and N‐nitroso‐N‐ethylurea in the variety ‘Nirmal’, which is resistant to dieback disease. These mutants were evaluated in the M3 and M4 generations. The dwarf and semidwarf mutants differed from the parental variety for many morphological characters, while the mutant with the wavy leaf margin differed mainly in leaf size and leaf thickness. Although both dwarf and semidwarf mutants showed a significantly higher alkaloid content in their roots in both generations, only the semidwarf mutant gave a significantly higher (23%) root alkaloid yield than the parental variety. The mutant with the wavy leaf margin showed a significantly higher alkaloid content in the leaves in both the M3 and M4 generations and also had a significantly higher (21%) leaf alkaloid yield than the parental variety. All three mutants were found to be controlled by monogenic recessive genes; the genes for ‘dwarfness’ and ‘semidwarfness’ were allelic to each other, with the allele for semidwarfness being dominant over the allele for dwarfness. The gene for the wavy leaf margin was inherited independently of the genes for dwarfness and semidwarfness.
Anther and isolated microspore culture response of wheat lines from northwestern and eastern Europe
Authors: Holme I. B. , Olesen A. , Hansen N. J. P. , Andersen S. B.
Published: March 2003

Hexaploid wheat genotypes from north‐western Europe show low responses to current anther culture techniques. This phenomenon was investigated on 145 north‐western European wheat lines. Twenty‐seven lines from eastern Europe were included to observe the response pattern of wheat from an area, where the technique has been used successfully. On average, eastern European wheat lines produced 3.6 green plants per 111 anthers, while only 1.4 green plants per 111 anthers were obtained in north‐western European lines. This difference was due to the high capacity for embryo formation among the eastern European lines, while the ability to regenerate green plants was widespread in both germplasm groups. Isolated wheat microspore culture performed on 85 of these wheat lines gave an average 3.7‐fold increase in green plants per anther compared with the anther culture response. The increased recovery of green plants was due to improved plant regeneration and increased green plant percentage from embryos derived from isolated microspore culture.
Male sterility in populations of Daucus and the development of alloplasmic male‐sterile lines of carrot
Authors: Nothnagell T. , Straka P. , Linke B.
Published: March 2003

A collection of Daucus species and subspecies, as well as alloplasmic carrot lines were evaluated for expression of male sterility. More than 100 male‐sterile plants were identified and their phenotypes and partial genetic background were characterized. Three potentially new cytoplasmic male‐sterile systems based on the cytoplasm of Daucus carota (D. c.) gummifer, D. c. maritimus and D. c. gadecaei were selected. Genetic analyses suggested that a nuclear‐cytoplasmic interaction determined the male sterility of the three sources. A clear differentiation between the new sources and carrot cultivars was possible based on the phenotypic and molecular genetic relationships.
Evaluation of amplified fragment length polymorphism markers in tef, Eragrostis tef (Zucc.) Trotter, and related species
Authors: Ayele M. , Nguyen H. T.
Published: March 2003

Tef is an important cereal crop in Ethiopia. This study was conducted to investigate (1) genetic diversity within and among three Eragrostis species (E. tef, E. pilosa and E. curvula), and (2) the relationship between E. tef, E. pilosa and E. curvula. A total of 529 AFLP markers were obtained, out of which 58% (368) were polymorphic, using 10 primer, combinations. The three species were separated distinctly using amplified fragment length polymorphism (AFLP), However, diversity revealed at the morphological trait level was not commensurate with that observed for AFLP. This was due to the small number of morphological traits available and their interaction with the environment. Within tef, ‘Rubicunda’ and DZ‐01‐1093 were found to be distantly related to the rest of the tef accessions. The diversity within species was such that E. pilosa was the most diverse followed by E. curvula and E. tef. Moreover, E. pilosa was more closely related to E. tef than E. curvula. Therefore, further study is needed of E. pilosa accessions and of ‘Rubicunda’ and DZ‐01‐1093 in a crossing programme to generate a population for selection and/or genetic mapping. A total of 19 cultivars or accessions had one or more unique fragments using one or more AFLP primers, indicating the potential of the technology in fingerprinting tef in a breeding or seed multiplication programme.
Genetic analysis of resistance in barley to barley yellow dwarf virus
Authors: Ovesná J. , Vacke J. , Kucera L. , Chrpová J. , Nováková I. , Jahoor A. , Š Ip V.
Published: March 2003

The inheritance of resistance to barley yellow dwarf virus (BYDV) was studied in the selected 24 spring and winter barley cultivars that showed a high or intermediate resistance level in 1994‐97 field infection tests. The polymerase chain reaction diagnostic markers YLM and Ylp were used to identify the resistance gene Yd2. The presence of the Yd2 gene was detected with both markers in all the resistant spring barley cultivars and lines from the CIMMYT/ICARDA BYDV nurseries. The results of field tests and genetic analyses in winter barley corresponded with marker analyses only when the Ylp marker was used. Genes non‐allelic with Yd2 were detected by genetic analyses and the Ylp marker in moderately resistant spring barley cultivars ‘Malvaz’, ‘Atribut’ and ‘Madras’, and in the winter barley cultivars ‘Perry’ and ‘Sigra’. Significant levels of resistance to BYDV were obtained by combining the resistance gene Yd2 with genes detected in moderately resistant cultivars. The utilization of analysed resistance sources in barley breeding is discussed.
Cytogenetic studies in wheat XIX. Chromosome location and linkage studies of a gene for leaf rust resistance in the Australian cultivar ‘Harrier’
Authors: Singh D. , Park R. F. , Bariana H. S. , McIntosh R. A.
Published: March 2003

Monosomic analysis indicated that a seedling leaf rust resistance gene present in the Australian wheat cultivar ‘Harrier’(tentatively designated LrH) is located on chromosome 2A. LrH segregated independently of the stripe rust resistance gene Yr1 located in the long arm of that chromosome, but failed to recombine with Lr17 located in the short arm. LrH was therefore designated Lr17b and the allele formerly known as Lr17 was redesignated as Lr17a. The genes Lr17b and Lr37 showed close repulsion linkage. Tests of allelism indicated that Lr1 7b is also present in the English wheats ‘Dwarf A’(‘Hobbit Sib’), ‘Maris Fundin’ and ‘Norman’. Virulence for Lr17b occurs in Australia, and pathogenicity studies have also demonstrated virulence in many western European isolates of the leaf rust pathogen. Despite this, it is possible that the gene may be of value in some regions if used in combination with other leaf rust resistance genes.
Genetic analysis of four self‐incompatible lines in Brassica napus
Authors: Yang G. S. , Chen C. B. , Zhou G. L. , Geng C. N. , Ma C. Z. , Tu J. X. , Fu T. D.
Published: March 2003

Reciprocal hybridization between four self‐incompatible lines of Brassica napus: 271, 181, 184 and ‘White Flower’, revealed incompatibility. The reciprocal F1s obtained by bud pollination showed self‐incompatible reactions, and no segregation for self‐incompatibility was observed in all the reciprocal F2 populations, indicating that lines 271, 181, 184 and ‘White Flower’ were genetically identical with regard to self‐incompatibility. Observations of self‐incompatibility in 17 hybrids from crosses between line 271 and 17 varieties of B. napus showed 10 of the F1 hybrids to be self‐compatible, while four were partially self‐compatible and three were self‐incompatible. Genetic analysis based on F2 and BC1 populations from five self‐compatible F1 hybrids and two self‐incompatible F1 hybrids suggested the existence of at least two loci controlling the self‐incompatibility of line 271: one is the S locus, with dominant and recessive relationships between the S alleles, and the other is the suppressor (sp) of the S locus. The sp locus is genetically different from the S locus, and also shows dominant and recessive relationships between the sp alleles.
Development of SCAR markers linked to the Ns locus in potato
Authors: Marczewski W. , Talarczyk A. , Hennig J.
Published: March 2003

A random amplified polymorphic DNA marker OPG17450 linked to the Ns gene that confers resistance of potato to potato virus S (PVS), was used to develop sequence‐characterized amplified region (SCAR) markers. After cloning and sequencing of OPG17450 new polymerase chain reaction (PCR) primers were designed to generate dominant (SCG17321) and codominant (SCG17448) markers. For SCG17448, polymorphism between susceptible and resistant genotypes was recovered after digestion of the marker with the restriction enzyme Muni. In addition to the band corresponding to ‘susceptible’ allele that does not contain the Muni cleavage site, two bands of approximately 251 bp and 197 bp were observed in the resistant genotypes. The usefulness of these SCAR markers was verified in diploid potatoes possessing the Ns locus from clone G‐LKS 678147/60, and in tetraploid potatoes derived from G‐LKS 678147/60 and from clone MPI 65118/3.
Molecular cytogenetic characterization of Thinopyrum genomes conferring perennial growth habit in wheat‐ Thinopyrum amphiploids
Authors: Cai X. , Jones S. S. , Murray T. D. , Weber W. E.
Published: March 2003

Seven wheat‐Thinopyrum amphiploids, AT 3425, AgCs, PI 550710, PI 550711, PI 550712, PI 550713 and PI 550714, were evaluated for perennial growth habit in the field. Three of them, AgCs, AT 3425, and PI 550713, were identified as perennials. Fluorescent genomic in situ hybridization (FGISH) patterns of mitotic chromosomes indicated that AgCs had seven pairs of Thinopyrum chromosomes and 21 pairs of wheat chromosomes. PI 550713 and AT 3425 showed similar FGISH patterns of mitotic chromosomes with three pairs of wheat‐Thinopyrum translocated chromosomes, seven pairs of Thinopyrum chromosomes, and 18 pairs of wheat chromosomes. Thinopyrum chromosome pairing in the Fi hybrid of AT 3425 with AgCs demonstrated differences between Thinopyrum genomes in these two amphiploids. Based on chromosome constitutions, pairing and reported pedigrees, AgCs and AT 3425 were identified as a wheat‐Thinopyrum elongatum amphiploid and partial wheat‐Thinopyrum ponticum amphiploid, respectively. Chromosome pairing in the F1 hybrid between AT 3425 and PI 550713 revealed that these two amphiploids contained the same Thinopyrum genome. Two different Thinopyrum genomes conferring perennial growth habit were identified from the perennial amphiploids and characterized cytogenetically.
Mapping boron efficiency gene(s) in Brassica napus using RFLP and AFLP markers
Authors: Xu F. S. , Wang Y. H. , Meng J.
Published: March 2003

Soil boron (B) deficiency, a world‐wide problem in agriculture, exists for more than 33 million hectares of cultivated land in China. Genetic variation exists for B‐efficiency among different Brassica napus germplasms. To identify genes controlling B efficiency, an F2 population of B. napus was constructed from a cross between a high B‐efficiency cultivar, ‘Qingyou 10’, and a low B‐efficiency cultivar, ‘Bakow’, and then evaluated for seed yield, bolting date and maturity date under B‐deficient conditions. The ratio of high B‐efficiency to low B‐efficiency individuals fitted the expected ratio of 3:1, indicating a major gene controlling the B‐efficiency trait. The major gene was mapped in the ninth linkage group of B. napus. Genome‐wide quantitative trait loci (QTL) analyses detected one major locus near the major gene, which explained 64.0% of the phenotypic variance. At the same time, three minor loci in three linkage groups were also detected, and these minor loci individually explained 39.2%, 32.5% and 36.9%, respectively, of the phenotypic variance. A total of 11 QTLs were detected for bolting date and maturity date, some of which were associated with B‐efficiency.
Alteration of the genomic composition of Solanum nigrum (+) potato backcross derivatives by somatic hybridization: selection of fusion hybrids by DNA measurements and GISH
Authors: Horsman K. , Gavrilenko T. , Bergervoet M. , Huigen D.‐J. , Joe A. T. W. , Jacobsen E.
Published: March 2003

Fusion experiments were performed with a first (BC1‐6738) and a second (BC2‐9017) generation backcross hybrid of 6x Solarium nigrum (+) 2x potato somatic hybrids with potato cultivars. Because no progeny was obtained from the BC2 genotypes, alternative approaches were sought to overcome the sexual crossing barrier. Five potato genotypes, one of which contains the hygromycin resistance gene, were used in the fusion experiments. All vigorous regenerants were used for the estimation of nuclear DNA content using flow cytometry. Plants with a DNA content higher than that of the BC1‐6738 or BC2 genotypes were considered potential somatic hybrids. Forty‐nine potential somatic hybrids resulted from fusion experiments with BC1‐6738, from which 20 grew vigorously in the greenhouse and flowered. After pollination with several 4x potato cultivars, eight genotypes produced seeded berries and five genotypes gave seedless berries. In addition, 11 of these 13 somatic hybrids were selected for genomic in situ hybridization (GISH) analysis to determine their genomic composition. Nine had exactly or approximately the expected number of 36 S. nigrum and 60 potato chromosomes. In one genotype, only 22 instead of 36 S. nigrum chromosomes were found and one potato chromosome was possibly missing. Only five potential somatic hybrids were detected among the 79 regenerants from BC2‐9017 (+) 2x potato fusion experiments that were analysed by flow cytometry. Two of these hybrids were rather vigorous and did flower, but pollinations with potato have not yet set any berries.
Comparison of genetic diversity of flax (Linum usitatissimum L.) between Canadian cultivars and a world collection
Authors: Diederichsen A.
Published: March 2003

This study reports results of phenotypic measurements of genetic diversity in the world collection of flax maintained by Plant Gene Resources of Canada (PGRC) and compares the range of diversity in the world collection with the diversity observed in 19 Canadian registered flax cultivars. Morphological and seed‐oil characters were used to describe the phenotypic diversity in 2331 flax accessions. The plants were grown by PGRC at Saskatoon, Saskatchewan, Canada, in 1998 and 1999. The comparison between the Canadian cultivars and the world collection was based on single characters, as well as on character complexes by application of an existing intraspecific classification for the species. Considering single quantitative or qualitative character expressions, the Canadian cultivars represented a wide range in diversity for the species. The variation of characters Canadian plant breeders have selected for (e.g. plant height, seed weight, seed colour, petal colour, oil content) was reduced further than those characters not focused on by plant breeders (e.g. dotting of the sepals, style colour, ciliation of capsule septa, oil quality characters). A comparison of diversity based on the intraspecific classification proposed for flax by Kulpa and Danert, who described 28 botanical varieties, showed that all Canadian cultivars belong to two botanical varieties. This study demonstrates the usefulness of agrobotanical characterization of genebank collections for plant breeding and illustrates the application of the traditional method of intraspecific classification for comparison of gene pools.
The inheritance of resistance to the blossom weevil, Anthonomus rubi, in the cultivated strawberry, Fragaria×ananassa
Authors: Simpson D. W. , Easterbrook M. A. , Bell J. A.
Published: March 2003

The objective of this research was to determine which strawberry germplasm could be used to combine late flowering with reduced susceptibility to the strawberry blossom weevil, Anthonomus rubi. Seven cultivars and three breeding lines were compared for their susceptibility to A. rubi, by introducing adult weevils onto detached inflorescences. No consistent differences were detected but this contradicted observations from field trials. Five late‐flowering strawberry genotypes were crossed in a half‐diallel programme and progeny were tested for their susceptibility to A. rubi by using detached inflorescences and in a field trial where plants were exposed to a natural infestation. There was good correspondence between the results from the two methods and heritable differences were detected in both experiments, with the additive genetic variance being the more important. The cultivars ‘Idea’ and ‘Alice’ were identified as promising parents for reduced susceptibility while progeny from ‘Sophie’ were most likely to be susceptible.
Impact of puroindoline b alleles on the genetic variation for hardness in soft × hard wheat crosses
Authors: Lillemo M. , Ringlund K.
Published: March 2003

Wheat grain hardness is controlled by one major genetic factor, the puroindoline hardness (ha) locus on the short arm of chromosome 5D, but there is also evidence for other minor genetic factors modifying the effect of puroindoline alleles. In this study, the progeny of nine soft × hard wheat crosses was evaluated for kernel texture, and the allelic state of puroindoline b (pinB) was assessed by polymerase chain reaction. The F2 populations of all nine crosses showed the expected 1:2:1 segregation ratio of homozygous soft, heterozygous medium and homozygous hard offspring. A model of variance components was constructed to separate the effects of pinB‐D1 allelic variation from other genetic factors affecting endosperm hardness. This model showed that pinB‐D1 allelic variation could explain 75‐93% of the genetic variation for hardness in the F2, but there were also significant contributions from other genetic factors in all the crosses. The feasibility of pinB‐D1 alleles as a molecular marker for hardness is demonstrated, and the results also indicate the possibility of breeding wheat varieties with true medium hardness.
Comparison of aluminium tolerance in the brassicas and related species
Authors: Huang B. , Liu Y. , Xue X. , Chang L.
Published: March 2003

The aluminium tolerance of 31 varieties within 11 species in six genera of the Cruciferae was determined by measuring root length under aluminium stress. Variance analysis indicated highly significant differences of aluminium tolerance among the species compared. Raphanus sativus (2n= 18, RR) had the highest aluminium tolerance, followed by Brassica carinata (2n= 34, BBCC), Brassica oleracea (2n= 18°C) and Brassica napus (2n= 38, AACC), which had the C genome. There might be more than one gene for aluminium tolerance in the R and C genomes. Those species such as Brassica campestris (2n= 20, AA), Brassica nigra (2n= 16, BB), Brassica juncea (2n= 36, AABB), Arabidopsis thaliana (2n= 10, arar), Sinapis alba (2n= 24, alal), Cheiranthus cheiri (2n= 12, chch) and Orychophragmus violaceus (2n= 24, OO) that did not include the R or C genome had lower aluminium tolerances. Transfer of aluminium tolerance from R. sativus into the cultivated brassicas seems possible by intergeneric hybridization and the production of addition, substitution or translocation lines.
Sequence tagged site markers linked to the sbm1 gene for resistance to pea seedborne mosaic virus in pea
Authors: Frew T. J. , Russell A. C. , Timmerman‐Vaughan G. M.
Published: March 2003

Resistance to pea seed‐borne mosaic virus (PSbMV) pathotype P‐1 in peas is conferred by sbm1 with recessive inheritance. PSbMV is an economically important pathogen with world‐wide distribution that causes significant losses in pea yield and reduces seed and produce quality. The sbm1 gene was previously mapped to linkage group VI on molecular linkage maps of the pea genome. To improve plant breeders’ ability to develop varieties resistant to PSbMV, two random amplified polymorphic DNA markers (G05_2537 and L01_910) and one restriction fragment length polymorphism (P446) linked to sbm1 have been identified. The genomic sequences for these markers have been characterized and the information used to develop three simple polymerase chain reaction‐based STS (sequence tagged site) assays. Linkage analysis in two F2 populations showed that the most tightly linked of these three STS loci (sG05_2537) is approximately 4 cM from sbm1. Characterization of a collection of resistant and susceptible germplasm demonstrated a strong correlation between STS alleles and sbm1 alleles, indicating the utility of these markers for marker‐assisted selection in breeding programmes using a range of germplasm sources.
Dry matter yield, herbage quality and persistency of equivalent populations of perennial ryegrass with and without reduced flowering
Authors: Wilkins P. W. , Rognli O. A.
Published: March 2003

Reducing the number of flowering tillers that perennial ryegrass produces would improve the feeding value of herbage and could also be used to reduce pollen flow to wild ryegrass populations. Equivalent populations with and without one or more genes that reduce flowering (normal and leafy populations, respectively) were compared over three harvest years (1999‐2001) in a field plot experiment with two cutting managements (silage and simulated grazing). In 1999, samples of dried herbage from each harvest were analysed for leaf lamina content, in vitro digestibility (DMD), crude protein (CP) and water‐soluble carbohydrate (WSC). The leafy population produced one‐fifth to one‐third as many reproductive tillers in May as did the normal population, depending on the management. Mean leaf content of the herbage over all harvests and managements was 63 g/kg higher in the leafy population but its mean DMD was only 7 g/kg higher. In August, September and October, when the leaf contents of the two populations were very similar, the mean DMD of the leafy population was 7 g/kg lower than that of the normal population. Mean annual dry matter yield over both managements of the leafy population was 6‐8% lower than that of the normal population but the leafy population was slightly more persistent.