bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on a Nigerian isolate of banana streak badnavirus: I. Purification and enzyme linked immunosorbent assay
Authors: THOTTAPPILLY G. , DAHAL G. , LOCKHART B E L 
Published: February 2008

SummaryA Nigerian isolate of banana streak badnavirus (BSV) was purified and a polyclonal antiserum was produced in mice. The antiserum titre was between 1:10 000 and 1:40 000 in enzyme linked immunosorbent assay (ELISA), and showed a good specificity to BSV antigens. Comparative tests were carried out to determine the sensitivity and reliability of BSV antigen detection by double antibody sandwich (DAS)‐ELISA, triple antibody sandwich (TAS)‐ELISA, antigen coated plate (ACP)‐ELISA, and protein‐A coated antibody sandwich (PAS)‐ELISA. TAS‐ELISA using rabbit polyclonal antiserum to trap BSV and mouse polyclonal antiserum to detect the virus particles, was more sensitive than ACP‐ELISA and PAS‐ELISA and detected BSV in plant extracts from both symptomatic and some asymptomatic plants. However, immunosorbent electron microscopy detected more BSV‐infected plants from asymptomatic plant samples than did TAS‐ELISA. Results of this study showed that detection of BSV antigens in sap extracts by TAS‐ELISA was most efficient with symptomatic tissues which occurred most frequently in the ‘cool rainy’ season. This suggests that for more reliable BSV‐indexing of field samples, tissue sampling should be done during the rainy season when most BSV‐infected plants express severe symptoms.
Studies on a Nigerian isolate of banana streak badnavirus: II. Effect of intraplant variation on virus accumulation and reliability of diagnosis by ELISA
Authors: DAHAL G. , PASBERG‐GAUHL C. , GAUHL F. , THOTTAPPILLY G. , HUGHES J d'A 
Published: February 2008

SummaryMonitoring of banana streak badnavirus (BSV) antigens and symptoms in naturally BSV‐infected plantain and banana (Musa spp.) plants showed a great variation in symptom expression, distribution and relative concentration of BSV between and within plants. Expression and distribution of symptoms was erratic within individual leaves as well as between different leaves of the same plant. The concentration of BSV antigens detected by triple antibody sandwich enzyme linked immunosorbent assay (TAS‐ELISA) varied in different plant parts including leaf lamina, midrib and pseudostem, roots and young ‘cigar’ leaf. The concentration of BSV antigens was high in symptomatic tissues but was low or below the limits of detection in most asymptomatic tissues. During ‘hot dry’ seasons when symptoms were not fully expressed, the concentration of BSV antigens in leaf tissues declined drastically, often below the detection limit of TAS‐ELISA. These results suggested that for more reliable detection of BSV antigens by TAS‐ELISA, it is advisable to index plants using composite tissue samples comprising as many leaves as possible for each plant and collected during cool and/or rainy seasons when symptom expression is generally severe.
The effect of seed dormancy on percentage and rate of germination in Polygonum persicaria, and its relevance for crop‐weed interaction
Authors: VLEESHOUWERS L M 
Published: February 2008

SummaryChanges in germination percentage and germination rate of Polygonum persicaria resulting from loss of primary dormancy during chilling of imbibed seeds were quantified. Both percentage and rate of germination increased with increasing loss of dormancy. It was concluded that retardation of germination caused by dormancy was not due to dormancy release prior to germination, but to retardation of the germination process itself. When evaluated in relation to competition between sugar‐beet and P. persicaria, the effect of dormancy on the germination percentage was more important than the effect on germination rate, but for an accurate prediction of yield loss, the latter effect cannot be neglected.
The response of dodder {Cuscuta spp.) seedlings to phytohormones under various light regimes
Authors: HAIDAR M A , ORR G L , WESTRA P. 
Published: February 2008

SummaryPhytohormones were screened for their effects on induction of coiling and prehaustoria in de‐etiolated excised dodder seedlings under different light treatments. Zeatin stimulated coiling and the formation of prehaustoria under all light tested, even in darkness. A synergistic effect was observed with zeatin and far‐red light (700–800 nm) but not with red light (600–700 nm) on the formation of prehaustoria. Application of indole‐3acetic acid inhibited zeatin‐induced coiling and prehaustoria development under blue (400–500 nm) and a mixture of red plus far‐red light, but not in blue plus far‐red light. Ethylene had no effect on coiling and prehaustoria development. Observations suggest that zeatin‐induced coiling and prehaustoria development may be mediated by phytochrome.
Canola seed germination and seedling emergence from pre‐hydrated and re‐dried seeds subjected to salt and water stresses at low temperatures
Authors: ZHENG G H , GAO Y P , WILEN R W , GUSTA L V 
Published: February 2008

SummaryLow soil temperatures and low water potentials reduce and delay the seed germination of canola (Brassica rapa L., B. napus L.) in western Canada. Germination is also very sensitive to the salinity effects of nitrogen fertiliser placed with the seed, especially when the seed bed is relatively dry. The effects of pre‐hydration and re‐drying treatment on canola (Brassica rapa L. cv. Tobin) seed germination and seedling emergence at 10°C subjected to either a water or salt stress were determined. Low water potentials, induced by polyethylene glycol (PEG 8000), low soil moisture, or high concentrations of salts, reduced both germination and seedling emergence, and increased the time to 50% germination and emergence of seeds at 10°C. At equal osmotic potentials, Na2SO4 was less inhibitory on low temperature germination than either NaCl or PEG, suggesting that the sulphate ion partially alleviated the inhibitory effects of low water potential. Solutions of NaCI produced more abnormal seedlings compared to Na2SO4, suggesting that NaCl was more toxic than Na2SO4 during seedling development. Pre‐hydration and re‐drying partially overcame the inhibitory effects of both low water potential and salts on seed germination and seedling emergence at 10°C. The seed treatment increased the germination rate in Petri dishes and seedling emergence from a sandy loam soil. Water potentials or soil water contents required to inhibit 50% germination or emergence at 10°C were lower for treated seeds compared to control seeds. Salt concentrations inhibiting 50% emergence were higher for treated seeds than control seeds. Neither treated nor control seeds produced seedlings which emerged if the soil water content was lower than 9% or when the soil was continuously irrigated with salt solutions of 100 mmol kg‐1 of NaCl or 50 mmol kg‐1 of Na2SO4. These results suggest that the pre‐hydration and re‐drying treatment did not lower the base water potentials at which seedling emergence could occur. Abnormal seedlings were observed in both treated and control seeds, particularly if the soil was watered with NaCl solutions; however, the seed treatment reduced the number of abnormal seedlings.
Phylogenetic relationships of coconut phytoplasmas and the development of specific oligonucleotide PCR primers
Authors: TYMON A M , JONES P. , HARRISON N A 
Published: February 2008

SummaryUsing the polymerase chain reaction the 16S rRNA genes and the 16S‐23S spacer regions of phytoplasmas associated with lethal decline diseases of coconut palm (Cocos nucifera), were amplified from infected plants from Florida and the Yucatan region in Mexico and from east and west Africa. Following sequencing of the rDNA products, phylogenetic analysis confirmed that these coconut phytoplasmas form a separate cluster within the phytoplasma clade and that the pathogen causing diseases in west Africa formed a new sub‐clade within this cluster. Analysis of the 16S‐23S intergenic spacer regions confirmed the sequence diversity of this region and enabled two primers to be designed which were specific for the diseases found in east and west Africa. None of these specific primers, when paired with a universal primer, produced PCR amplification products from healthy coconut DNA, infected coconut DNA from the Caribbean or DNA from a variety of periwinkle (Catharanthus roseus)‐maintained phytoplasmas. These specific primers can serve as effective tools for identifying particular coconut phytoplasmas in field samples.
Sources of resistance to groundnut rosette disease in global groundnut germplasm*
Authors: SUBRAHMANYAM P. , HILDEBRAND G L , NAIDU R A , REDDY L J , SINGH A K 
Published: February 2008

SummaryAbout 6800 groundnut germplasm accessions originating from South America, Africa, and Asia were evaluated for resistance to rosette disease using an infector row technique between the 1990/91 and 1996/97 growing seasons. Of these, 116 germplasm accessions, including 15 short‐duration Spanish types, have shown high levels of resistance to rosette disease. A high percentage of these resistant accessions were from West Africa and a few were from Asia and southern Africa. Only one out of 1400 accessions from South America showed resistance to rosette disease. All disease‐resistant accessions were susceptible to groundnut rosette assistor virus. This is the first report to identify sources of resistance to rosette disease in groundnut germplasm from Asia and South America. These additional sources of resistance provide an opportunity to broaden the genetic base of resistance to rosette disease. The origins of rosette resistance in groundnut are discussed.
The design and analysis of breeders' trials of sugar beet (Beta vulgaris) using two‐dimensional blocking structures
Authors: ZHAO B. , MEAD R. , MACKAY I J , CALIGARI P D S 
Published: February 2008

SummaryA method for generating two‐dimensional blocking designs to fit any shape and size of experimental area is presented. The method takes an alpha design appropriate to the experimental area and imposes additional blocking perpendicular to the alpha blocks. Improvements to the design are then made by repositioning entries within the alpha blocks. Although this method of construction is less sophisticated than for other two‐dimensional designs, the designs are particularly suited to large scale breeders trials where no alternative two‐dimensional design may exist. The designs have been used for 3 yr in a sugar beet breeding programme, and have given improvements in efficiency over one‐dimensional alpha designs.
Chemical control of Alternaria brown spot on Minneola tangelo in South Africa
Authors: SWART S H , WINGFIELD M J , SWART W J , SCHUTTE G C 
Published: February 2008

Summary.The effectiveness of several groups of fungicides was compared with that of copper and mancozeb for their ability to control Alternaria brown spot on Minneola tangelo. Variables used for comparing fungicides in order of importance were: performance index, the number of exportable fruits per tree, the number of fruits per tree free of Alternaria lesions and total number of fruits per tree. Percentage exportable fruits was not a reliable variable for comparing treatment efficiency.During the 1992/1993 evaluations iprodione, difenoconazole, and procymidone showed promising control of the disease. Other than for difenoconazole, members of the triazole group were not effective, especially at dosages below 10 g a.i. 100 litre ] water. Moderate control of Alternaria brown spot was obtained using copper and mancozeb. During the 1993/1994 season spray programmes with copper oxychloride, mancozeb, maneb plus zinc oxide, procymidone, iprodione, and tebuconazole were compared in field trials, for the control of Alternaria brown spot on Minneola tangelo. Mancozeb applied at 2‐weekly intervals was the most effective spray programme, followed in order of efficiency by programmes using procymidone, maneb plus zinc oxide, and mancozeb applied at 4‐ and at 3‐weekly intervals. Iprodione and tebuconazole were not particularly effective in this evaluation, although they performed significantly better than the control treatment. Trees treated with copper oxychloride produced poorly, in spite of a high percentage exportable fruits.
Effects of cold shock on the susceptibility of white lupins to fungal diseases
Authors: ETHERIDGE J V , BATEMAN G L 
Published: February 2008

Summary.Experiments in controlled environments tested interactions between freezing soil (a compost‐vermiculite mixture) and below‐ground infection of white lupins with each of three pathogenic fungi (Botrytis cinerea, Fusarium avenaceum or Pleiochaeta setosa) on plant disease and death. Whilst soil freezing (up to 4 days at – 1oC) caused slight necrosis and increased the severity of disease symptoms, incidence of plant death was increased only after inoculation, before freezing, of the lower hypocotyl of the youngest plants (soil frozen at less than 17 days old) with P. setosa. It is concluded that the contribution of below‐ground infection by pathogenic fungi to overwinter losses in autumn‐sown white lupin crops is exacerbated to a negligible extent by soil freezing, the main primary cause of such losses.
Serological identification and quantification of potato cyst nematodes from clean cysts and processed soil samples
Authors: CURTIS R H C , DUNN J. , ROBINSON M P , MARTINS F. , EVANS K. 
Published: February 2008

Summary.Two monoclonal antibodies which specifically recognise each of the two species of potato cyst nematodes (PCN) and do not cross react with other species of soil nematodes, were used successfully in an immunoassay to identify and quantify PCN species using clean cysts and mixed populations. These antibodies show reactivity only towards antigens prepared from live eggs and they recognise antigens which are easily released from the nematodes. The results presented in this paper show that serological identification and quantification of PCN, not only from clean cysts but also from processed soil samples is achievable. A simple procedure to recover nematodes from soil samples and then to release nematode antigens was devised. The use of these procedures and the immunoassay for quantification of PCN was validated in tests with soil samples from Northern Portugal. The flotation method proved to be as efficient as the Fen wick Can for cyst recovery from soil samples. A significant correlation was obtained between results from immunoassay estimates and the traditional method of cyst picking and egg counting. The amount of organic matter (OM) present in the soil samples affected the sensitivity of the immunoassay but quantification of nematodes extracted from soil samples was possible with soils containing up to 14% of OM. The challenge remains to optimise the extraction procedures and the immunoassay, in practical conditions with highly organic soils containing cysts of different sizes and ages.
A chamber for the simulation of radiation freezing of plants
Authors: FULLER M P , GRICE P LE 
Published: February 2008

Summary.Frost injury to plants can occur following episodic radiation frosts. In the UK this is particularly important to spring sown crops such as potatoes. Most laboratory based frost studies simulate freezing using either conductive or convective freezing chambers. Such frost tests do not simulate overnight freezing events adequately.A freezing chamber based on radiative cooling is described which mimics overnight radiative freezing. The chamber is rectangular in design (1 m × lm × 2 m high) with a radiative cooling plate at the top of the chamber cooled to ‐40°C to ‐45°C using HFC coolants, which acts as a cold black body. The sides of the chamber are also cooled to variable temperatures down to ‐5°C in order to prevent the chamber walls radiating to the plant material during testing.Using thermocouples to measure air temperature and plant temperature the chamber has been characterised to simulate the radiative cooling conditions found in the UK during autumn and spring. Exotherm detection upon plant freezing is simplified by virtue of the reduction in temperature fluctuation normally experienced at the plant surface during natural freezing. Radiation frosts and subsequent frost damage to potatoes have been recorded in the temperature range ‐4°C to –5°C. The equipment is recommended for studies of frost damage to plants normally caused by episodic radiation frost events.
The palatability of 78 wildflower strip plants to the slug Arion lusitanicus
Authors: BRINER T. , FRANK T. 
Published: February 2008

Summary.AsArion lusitanicushas been observed in high densities in wildflower strips, the palatability of the foliage of 78 species of sown and naturally occurring plants found in such strips was investigated. In the laboratory, the slugs were offered a surplus of fresh, mature leaves and, after 16 h, a consumption index was calculated to rank the plants according to their palatability to the slugs.Arion lusitanicusshowed clear preferences for particular plant species, but more than two thirds of all plants investigated were scarcely eaten.Brassica napuswas most eaten, followed byPapaver rhoeas, Capsella bursa‐pastorisandLamium purpureum.Overall,A. lusitanicuspreferred sown species to naturally occurring ones and preferred annuals to perennials.
Sclerospora graminicola‐ and arachidonic acid‐induced autofluorescence in downy mildew resistant and susceptible genotypes of pearl millet
Authors: GEETHA S. , SHETTY SUDHEER A , SHETTY H SHEKAR , PRAKASH H S 
Published: February 2008

Summary.Autofluorescence of downy mildew resistant and susceptible cells of pearl millet seedlings undergoing hypersensitive reaction (HR) upon Sclerospora graminicola‐inoculation and arachidonic acid (AA)‐treatment was studied. Two‐day‐old seedlings of a highly resistant (IP 18296) and a highly susceptible (23D2B) genotype of pearl millet were either inoculated with zoospore suspension of S. graminicola or treated with AA for 24 h. The coleoptiles with hypersensitive necrotic spots were processed by the standard procedure, and the tissues were subjected to fluorescence microscopy. A differential accumulation of autofluor‐escent compounds in resistant and susceptible pearl millet genotypes was observed with most accumulation occurring in resistant cells treated with AA. The variation in the degree of fluorescence and the spatial accumulation of autofluorescent compounds among the two inoculated/treated genotypes is discussed.
The case for headland set‐aside: consideration of whole‐farm gross margins and grain production on two farms with contrasting rotations
Authors: SPARKES D L , RAMSDEN S J , JAGGARD K W , SCOTT R K 
Published: February 2008

Summary.Spreadsheet calculations were used to compare headland set‐aside with rotational set‐aside in terms of gross margin and grain production on two farms with contrasting rotations. At Broom's Barn, Suffolk there was a five course rotation consisting of sugar beet and four cereals, while at Bunny Park, Nottinghamshire oilseed rape was the break crop, followed by three cereals. For both farms a sensitivity analysis was used to investigate the effect of the proportion of the farm required to be set aside, the extent of headland yield reduction and the cereal price on the outcome of the spreadsheet calculations.In general headland set‐aside out‐performed rotational set‐aside. Yields on headlands were always less than the main body of the field, but it was on the turning headlands where yield was particularly depressed. Thus the advantage, in terms of gross margin, of setting aside the headlands was greatest when the requirement could be fulfilled by fallowing most turning headlands, but no non‐turning headlands.Generally, rotational set‐aside reduced grain production more than headland set‐aside, but when the spreadsheet models were adjusted to maintain the area of sugar beet, the situation was reversed. In this case headland set‐aside produced a larger gross margin and had the greatest impact on grain production.An extension of the analysis is to ask the question: even if set aside is not an option, is it worthwhile to crop rather than fallow headlands? For cereals and oilseed rape the answer is in the affirmative; the gross margin for headlands remains positive, even when prices are much reduced, because the arable area payment more than offsets the variable costs. This does not hold for crops such as sugar beet that are not eligible for arable area payments.An additional benefit from headland set‐aside is its potential to enhance the environment through increased habitat diversity and the provision of ‘buffer zones’ to prevent agrochemicals from drifting into hedges and watercourses.
The potential benefits from cultivar specific red clover ‐potato crop rotations
Authors: STURZ A V , CHRISTIE B R 
Published: February 2008

Summary.The aim of this study was to determine if endophytic bacteria could contribute to cultivar specific interactions between red clover(Trifolium pratenseL.) and potatoes(Solanum tuberosumL.) in crop rotations. Endophytic bacteria were isolated from the roots of four red clover cultivars (AC Charlie, Altaswede, Marino and Tempus) grown in the field. Populations of bacteria from each cultivar were similar. The most abundant genus wasRhizobium,but species ofCurtobacterium, Pseudomonas,andXanthomonaswere common to all cultivars. Plantlets of two potato cultivars, Russet Burbank and Shepody, were inoculated individually with the seven bacterial isolates most frequently recovered from each red clover cultivar, and grown in Magenta vessels for 6 wk. Significant differences were found for plant height, and wet weights of roots, shoots and their total. Potato cultivars differed for root wet weight only, while red clover cultivar, as a source of bacteria, had a significant effect on all traits except plant height. Differences among bacteria were significant for all traits except shoot wet weight. There was a significant interaction of potato cultivar by red clover cultivar. The potato cultivar Russet Burbank did best with bacteria from the red clover cultivar, Marino; and Shepody, with bacteria from Altaswede.