bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification and potential use of RAPD markers linked to Yam mosaic virus resistance in white yam (Dioscorea rotundatd)
Authors: MIGNOUNA H D , ABANG M M , ONASANYA A , AGINDOTAN B , ASIEDU R
Published: July 2006

Resistance to Yam mosaic virus (YMV) in tetraploid white yam (Dioscorea rotundatd) is inherited differentially as a dominant and recessive character. Elite D. rotundata breeding lines with durable resistance to YMV can be developed by pyramiding major dominant and recessive genes using marker‐assisted selection (MAS). The tetraploid breeding line, TDr 89/01444, is a source of dominant genetic resistance to yam mosaic disease. Bulked segregant analysis was used to search for random amplified polymorphic DNA (RAPD) markers linked to YMV resistance in F1 progeny derived from a cross between TDr 89/01444 and the susceptible female parent, TDr 87/00571. The F1 progeny segregated 1:1 (resistantsusceptible) when inoculated with a Nigerian isolate of YMV, confirming that resistance to YMV in TDr 89/01444 was dominantly inherited. A single locus that contributes to YMV resistance in TDr 89/01444 was identified and tentatively named Ymv‐1. Two RAPD markers closely linked in coupling phase with Ymv‐1 were identified, both of which were mapped on the same linkage group: OPW18850 (3.0 centiMorgans [cM]) and OPX15850 (2.0 cM). Both markers successfully identified Ymv‐1 in resistant genotypes among 12 D. rotundata varieties and in resistant F1 individuals from the cross TDr 93–1 × TDr 877 00211, indicating their potential for use in marker‐assisted selection. OPW18850 and OPX15850 are the first DNA markers for YMV resistance and represent a starting point in the use of molecular markers to assist breeding for resistance to YMV.
Effects of Zygorrhynchus moelleri on the growth of potato and reproduction of potato cyst nematodes
Authors: KISSOCK By G , FLEMING C C , TURNER S J , BROWN A E
Published: July 2006

Laboratory, pot and field experiments investigated the effects of the fungus Zygorrhynchus moelleri on the growth of potato and on the reproduction of the potato cyst nematodes (PCN), Globodera pallida and G rostochiensis. Preliminary laboratory tests showed that Z. moelleri growth was favoured by temperatures and pH ranges commonly present in field soils. The fungus colonised potato roots in vitro and in compost or field soil. It also stimulated in vitro root growth of three potato cultivars. In pot experiments Z. moelleri stimulated potato growth, particularly in the presence of PCN attack. In field plots infested with a mixture of G pallida and G. rostochiensis, tuber yields were not increased after application of the fungus but, in G pallida‐infested plots, yields were significantly increased after drills were inoculated with Z. moelleri.

The application of Z. moelleri had no apparent effects on nematode reproduction. Factors influencing the interactions between Z. moelleri, potato and potato cyst nematodes are discussed and the potential role of the fungus as a plant growth promoter in organic potato production considered.
Effect of different manuring and defoliation patterns on broad‐leaved dock (Rumex obtusifolius) in grassland
Authors: HOPKINS A , JOHNSON R H
Published: July 2006

The effects of cutting frequency and cutting height on broad‐leaved dock (Rumex obtusifolius) in Lolium perenne‐based agricultural grassland at two levels of fertiliser input were investigated at North Wyke, Devon, UK. Two micro‐plot field experiments, containing immature dock plants at uniform densities, with a factorial design, were used to compare: (a) ‘organic’ and ‘low‐input’ fertilisation, i.e. cattle slurry only vs slurry plus mineral fertiliser (NPK at 100‐0‐64 kg ha−1 yr−1), (b) cutting heights of 5–6 cm vs 10–12 cm, and (c) four harvesting frequencies representative of different grassland management practices (regular 4‐weekly cutting, a ‘hay‐stage’ cutting, and two treatments with ‘silage‐stage’ cutting). Expt 1 was established in 1995 with 13 dock plants m−2 (from excised dock‐root sections) and Expt 2 established in 1996 with 25 plants m−2 (as seed‐grown plug plants). Treatments were assessed over the 2 subsequent years to determine treatment effects on total herbage dry matter (DM) yield and dock DM yield, and on in‐situ measures of dock ramets. In both experiments, total DM yield was increased by 1.0–2.01 ha−1 yr−1 for treatments receiving NK fertiliser; the proportion of dock was also higher than from slurry‐only treatments. In Expt 1, the dock ramet density, mean dock ramet height, mean leaf length and numbers of dock leaves per m2 were also greater on NK fertilised treatments in autumn of yr 1. Height of cut had no consistent effect on dock yield, but dock ramet density and leaf density in autumn were greater on the 5–6 cm than the 10–12 cm cutting treatment, Expt 2 only. In yr 2 of both experiments cutting at 4‐weekly intervals resulted in less dock in the herbage than hay‐stage cutting and, particularly in Expt 1, there were associated differences in leaf density and ramet height in autumn; silage‐stage treatments were intermediate. Results are discussed in relation to requirements for management options where there is a need to avoid or reduce herbicides.
Feeding deterrent effect of carvone, a compound from caraway seeds, on the slug Arion lusitanicus
Authors: FRANK T , BIERT K , SPEISER B
Published: July 2006

The feeding deterrent effect of carvone on the slug Arion lusitanicus was investigated. Carvone, a natural compound from caraway seeds, was incorporated into mulch to reduce its inherent volatility. In a laboratory choice experiment, boxes were filled on one side with carvone‐treated mulch and on the other side with untreated mulch. At carvone concentrations ranging from 0.03–0.75 ml litre−1 mulch, slugs ate significantly more lettuce on the untreated side. In a laboratory based no‐choice experiment, carvone concentrations of 0.25 and 0.75 ml litre−1 mulch significantly reduced slug feeding in comparison with the untreated control. Moreover at the highest concentration of carvone (0.75 ml litre−1 mulch) 50% mortality was recorded over a period of 5 days, indicating a clear molluscicidal effect. Due to its volatility carvone did not decrease plant defoliation by A. lusitanicus when applied directly onto lettuce. Subsequent field evaluation showed 0.75 ml litre−1 mulch to partially reduce slug feeding damage. However, this effect was not sufficient to significantly increase lettuce yield. The incorporation of a higher carvone concentration into mulch is still to be tested to confirm whether carvone‐treated mulch can be recommended as an effective alternative approach to chemical slug control.
16S rRNA interoperon sequence heterogeneity distinguishes strain populations of palm lethal yellowing phytoplasma in the Caribbean region
Authors: HARRISON N A , MYRIE W , JONES P , CARPIO M L , CASTILLO M , DOYLE M M , OROPEZA C
Published: July 2006

DNA of phytoplasmas in lethal yellowing (LY)‐diseased palms was detected by a nested polymerase chain reaction (PCR) assay employing rRNA primer pair P1/P7 followed by primer pair LY16Sf/ LY16‐23Sr. Polymorphisms revealed by Hinfl endonuclease digestion of rDNA products differentiated coconut‐infecting phytoplasmas in Jamaica from those detected in palms in Florida, Honduras and Mexico. A three fragment profile was generated for rDNA from phytoplasmas infecting all 21 Jamaican palms whereas a five fragment profile was evident for phytoplasmas infecting the majority of Florida (20 of 21), Honduran (13 of 14) and Mexican (5 of 5) palms. The RFLP profile indicative of Florida LY phytoplasma was resolved by cloning into two patterns, one of three bands and the other of four bands, that together constituted the five fragment profile. The two patterns were attributed to presence of two sequence heterogeneous rRNA operons, rrnA and rrnB, in most phytoplasmas composing Florida, Honduran and Mexican LY strain populations. Unique three and four fragment RFLP profiles indicative of LY phytoplasmas infecting Howea forsteriana and coconut palm in Florida and Honduras, respectively, were also observed. By comparison, the Jamaican LY phytoplasma population uniformly contained one or possibly two identical rRNA operons. No correlation between rRNA interoperon heterogeneity and strain variation in virulence of the LY agent was evident from this study.
Genotype to phenotype: a technological challenge
Authors: WILSON IAN D , BARKER GARY L , EDWARDS KEITH J
Published: July 2006

Our ability to ascribe protein function from primary DNA sequence or to predict the wide‐ranging effects of up or down regulating a single gene is still almost non‐existent. While the acquisition of raw genomic data proceeds apace, our capacity for converting this information into useful knowledge is limited. Within the next few years this “gap” will no doubt become an issue with both company and government fund providers as the drive to maximise profit and justify public expenditure becomes harder to resist. What follows is a whistle stop tour of some of the technologies that may help researchers to bridge this genotype‐phenotype gap!
Caffeine as a novel toxicant for slugs and snails
Authors: HOLLINGSWORTH ROBERT G , ARMSTRONG JOHN W , CAMPBELL EARL
Published: July 2006

In this study, caffeine is shown to act as both a repellent and toxicant against slugs and snails. This research is the first to document the potential of caffeine as a molluscicide. A drench treatment using a 1% or 2% solution of caffeine caused 100% of slugs (Veronicella cubensis) to exit treated soil, and the majority of these slugs subsequently died from caffeine poisoning. A 2% solution of caffeine applied to the growing medium of orchids killed 95% of orchid snails, (Zonitoides arboreus), and gave better control than a liquid metaldehyde product representing the standard commercial control for this pest. Using leaf‐dip bioassays, we discovered that slugs tended to avoid feeding on plant material treated with caffeine solutions 0.1%, and caffeine solutions as low as 0.01% significantly reduced overall feeding by slugs. Due to concerns about chemical residues, available molluscicides generally cannot be applied directly to food crops for control of slug and snail pests. Caffeine is a natural product which is approved as a food additive. Therefore, caffeine may prove useful for protecting food crops from slugs and snails.
Water relations and leaf gas exchange properties in some elite canola (Brassica napus) lines under salt stress
Authors: QASIM M , ASHRAF M , JAMIL M AMIR , ASHRAF M Y , SHAFIQ‐UR‐REHMAN  , RHA EUI SHIK
Published: July 2006

In order to examine whether growth of eight genetically diverse canola (Brassica napus) lines under salt stress is positively associated with their rate of photosynthesis and other gas exchange related attributes, 20‐day old plants of all eight lines were subjected to salinised soil containing 2.4 dS m−1 NaCl (control), 4 dS m−1 NaCl, 8 dS m−1 NaCl or 12 dS m‐1 NaCl. The lines DGL (non canola) and Dunkeld were found to be salt tolerant and Rainbow and Cyclon salt sensitive with regard to shoot dry matter production and seed yield under saline conditions. In most of the lines there was a negative relationship between growth and net CO2 assimilation rate. For example, the salt sensitive line Cyclon was the lowest and Con‐III the highest, and the salt tolerant line Dunkeld intermediate in net CO2 assimilation rate under salt stress. Stomatal conductance was found to be lower in the salt sensitive line Cyclon, followed by the salt tolerant line Dunkeld along with Oscar. Water use efficiency estimated as Pn/E was moderate in the salt sensitive line Cyclon and the salt tolerant line Dunkeld. In conclusion, high salt tolerance of Dunkeld and DGL (non‐canola) was not positively associated with net CO2 assimilation rate or Pn/E.
The host range of Tobacco streak virus in India and transmission by thrips
Authors: PRASADA RAO R D V J , REDDY A S , REDDY S V , THIRUMALA‐DEVI K , RAO S CHANDER , MANOJ KUMAR V , SUBRAMANIAM K , YELLAMANDA REDDY T , NIGAM S N , REDDY D V R
Published: July 2006

Tobacco streak virus (TSV) recently caused an epidemic in peanut (= groundnut, Arachis hypogaea) crops in Andhra Pradesh, India. In the epidemic area TSV occurred in many widely distributed weeds of which Parthenium hysterophorus probably plays a major role in its spread by thrips. Three thrips species, Megalurothrips usitatus, Frankliniella schultzei and Scirtothrips dorsalis were vectors in the presence of infected pollen. Of crop species, Helianthus annuus (sunflower) and Tagetes patula (marigold) could act as sources of inoculum. In limited tests, the virus was not seed‐transmitted in the peanut cultivar JL‐24 or in the sunflower hybrids KBSH‐41, ‐42, ‐44, and ‐50, MSFH‐17 and ZSH‐976. Strategies adopted to reduce the incidence of TSV are discussed.
Serological and biological variations of African cassava mosaic virus, in Nigeria
Authors: OGBE F O , ATIRI G I , DIXON A G O , THOTTAPPILLY G
Published: July 2006

To determine the occurrence of variants of African cassava mosaic virus, 316 cassava leaf samples were collected from mosaic‐affected cassava plants in 254 farmers. fields in 1997 and 1998, covering the humid forest, coastal/derived, southern Guinea and northern Guinea savannas and arid and semi‐arid agroecologies of Nigeria. The samples were tested in triple antibody sandwich enzyme‐linked immunosorbent assay using a panel of 10 monoclonal antibodies (MAbs) against the virus in which 29 reaction patterns were observed. In cluster analysis, nine serotypes were obtained at 0.80 Jaccard similarity coefficient index in which at least 50% of isolates of each serotype reacted alike. The serotypes ranged between two extremes: serotype 1 with 90% isolates reacting with the 10 MAbs and serotype 8 in which 90% of its isolates failed to react with the antibodies. Isolates of serotypes 1, 2, 4 and 8 were widely distributed while those of the other serotypes were estricted to certain agroecologies. Four representative isolates 227 (serotype 1), 231 (serotype 2), 235 and 283 (serotype 8) elicited different responses in Nicotiana, benthamiana, with isolate 283 not able to infect this and other test plants used. The serological variations did not necessarily reflect the biological variations. In polymerase chain reaction tests, one out of the five pairs of ACMV primers tested distinguished only isolate 283. The humid forest, derived/coastal and southern Guinea savannas where most of the crop is grown in Nigeria had a high number of variants, which makes the agroecologies suitable for the selection of resistant cassava clones against ACMV.
Development of the magnetic capture system for recovery of Xiphinema americanum
Authors: CHEN Q , BROWN D J F , CURTIS R H C , JONES J T
Published: July 2006

Xiphinema americanum is listed as a quarantine nematode by The European Plant Protection Organisation because of its ability to transmit quarantine viruses. Detection of this nematode in soil samples, or in mixed nematode samples extracted from soil, is therefore of paramount importance. We recently described the use of magnetic beads (Dynabeads) in combination with probes such as lectins or antibodies for recovery of small endoparasitic nematodes including Meloidogyne spp. and Globodera rostochiensis from mixed nematode samples. Here we show that magnetic capture can be used with much larger nematodes such as X. americanum. We describe lectins and antisera that bind to the surface of this nematode and show that the antisera can be used in the Dynabeads system to recover and enrich X. americanum from mixed nematode samples.
Selection index for identifying high‐yielding groundnut genotypes in irrigated and rainfed environments
Authors: CHANDRA S , NIGAM S N , CRUICKSHANK A W , BANDYOPADHYAYA A , HARDCRISHNA S
Published: July 2006

Selection of high yielding genotypes to be carried over to subsequent selection cycles in a breeding programme can sometimes be accomplished using a suitable index of secondary traits that may be relatively less sensitive to genotype‐by‐environment interactions than yield. We used the concept of correlated response to selection to measure the relative efficiency of nine selection indices. The results showed that the selection index, based on median and semi inter‐quartile range, which was actually used in identifying high yielding genotypes, had an efficiency that is comparable to the best index, the latter being a modification of the Elston index.
Stay‐green compared with non‐stay‐green Lolium perenne in field swards with different cutting and nitrogen treatments
Authors: WILMAN D , IRIANNI RAM , HUMPHREYS M O
Published: July 2006

The purpose of this study was to investigate the effect of the stay‐green trait, originally introduced into perennial ryegrass (Lolium perenne) for amenity purposes, in field swards of stay‐green forage perennial ryegrass managed in different ways for agricultural use. The experimental treatments comprised all 18 combinations of two grass selections (stay‐green and non‐stay‐green), three intervals between cuts and three N treatments. The conclusions were that the introduction of the stay‐green trait (1) may not always confer greater greenness in the early life of a sward; (2) may confer greater greenness during leaf senescence more because carotenoids are unmasked to a lesser extent than because of a reduction in the length of leaf visibly senescing; (3) may reduce herbage yield, particularly when a long interval is allowed between defoliations; (4) may reduce the decline in the concentration of N in herbage during the latter part of a long period of regrowth; (5) may reduce the concentration of Na in herbage.
Aerated hydration treatment for improved germination and seedling growth in aubergine (Solarium melongena) and pepper (Capsicum annuum)
Authors: DEMIR I , OKCU G
Published: July 2006

Aerated hydration treatment of aubergine and pepper seeds at 25°C (42 h for aubergine, 48 h for pepper) followed by drying increased percent germination across a range of test temperatures (18°C, 25°C and 35°C). The increase in germination obtained by the treatment was retained in storage for up to 4 months. In a glasshouse experiment, aerated hydration decreased mean emergence time but increased seedling dry weight in both species and decreased the proportion of abnormal seedlings in pepper. This work suggests that aerated hydration treatment can improve establishment of these crops in a range of planting temperatures.
Drought effects on the dynamics of leaf production and senescence in field‐grown Medicago arborea and Medicago citrina
Authors: LEFI E , GULÍAS J , CIFRE J , BEN YOUNES M , MEDRANO H
Published: July 2006

Forage shrub production in the Mediterranean region is frequently limited by soil water availability. To study plant responses to water deficit under such conditions is important for improving crop management and for selecting better yielding forage shrub species. Pre‐dawn leaf water potential (Ψpd), plant leaf area (PLA), leaf area per stem (LAs), leaf appearance rate (LAR1;), leaf senescence rate (LSR), individual leaf area (LA) and maximal leaf elongation rate (LER) were studied throughout the year for Medicago arborea (MA) and Medicago citrina (MC) under irrigated (control) and low rainfall field conditions, at the experimental field site of the University of the Balearic Islands in Spain.

With irrigation, the highest LA and LER were observed in autumn and spring and the lowest in winter and summer. LAR; was similar for both species in autumn and winter. Throughout the spring, LAR1 was higher for MC compared to MA. PLA was similar for both species during the autumn, winter and spring seasons; however, during the summer PLA of MA was significantly reduced by 53%. This decline was attributed to higher leaf senescence during seed maturity. As a consequence, MC maintained higher leaf area (∼ 5 m2 plant−1) than MA (3 m2 plant−1).

Under natural field conditions, soil water deficit increased from February to late August. The main effect of water stress was a marked reduction in LAR1, LA and LER reflected in lower LAs and PLA. Leaf area was severely reduced for both species during the summer, but much more intensively in MA, which developed full leaf senescence. Thus, MC maintained higher PLA than MA (0.5 m2 compared to 0.0 m2). Throughout the year, but especially in the driest months, MC was superior to MA in leaf growth parameters and PLA.
Production of Phytophthora infestans oospores in planta and inoculum potential of in vitro produced oospores under temperate highlands and subtropical plains of India
Authors: SINGH B P , GUPTA JHILMIL , ROY S , RANA D K
Published: July 2006

High moisture content of the host tissue ( 88%) and low ambient r.h. (50‐54%) favoured oospore formation under controlled environments. It took 14–16 days for oospores to develop; thereafter the number of oospores increased with time and decreased with moisture content of host tissue. High ambient r.h. (> 80%) did not favour oospore formation under field or controlled conditions. Oospore formation was detected in inoculated plants grown in the field when the ambient r.h. declined to 74% and moisture content of host tissue decreased to 83.7–85.6%. It took 8 days (cv. Kufri Chandramukhi) to 13 days (cv. Kufri Jyoti and Kufri Badshah) for oospores to develop. Cultivars also differed in their response to oospore production, cv. Kufri Chandramukhi being more responsive (4800 oospores g−1 f wt) than cv. Kufri Jyoti and Kufri Badshah (1320 and 390 oospores g−1 f wt respectively). Oospores produced in vitro remained viable when buried in soil in the temperate highlands of Himachal Pradesh and sub‐tropical plains of Uttar Pradesh, India for more than 150 days, i.e. beginning of the next crop season. The oospores germinated and initiated late blight infection at the base of the stems after 21–30 days of incubation of the potato plants raised in oospore‐infested soil. It took 2 days for newly formed oospores to germinate and this delay time increased to 75–77 days after 180‐days burial. It took 15 days for their germination (47%) in soil extract as compared to 50 days in sterilised distilled water.
A mechanical investigation of the retting process in dew‐retted hemp (Cannabis sativa)
Authors: BOOTH I , GOODMAN A M , GRISHANOV S A , HARWOOD R J
Published: July 2006

Hemp (Cannabis sativa) produces phloem fibres, which are formed in bundles towards the periphery of the stem. This study investigated one aspect of the retting process, the dissociation of these fibres from the core of the stem, which is influenced by the action of micro‐organisms.

Peel tests were used to investigate the work required to remove a tissue peel, rich in fibres, from the core of the stem. Two separate experiments studied (1) the effects of tissue dehydration as stems were dried out in the oven; and (2) the progress of retting in stems that were dew‐retted in the field. A comparison between two different types of peel tests, where the stems were clamped either vertically or horizontally in the jaws of a tensile testing machine and the load applied vertically, showed that the work required to peel stems in the vertical position was over 20% greater than that for the horizontal position.

Freshly harvested stems were dehydrated in an oven at 40°C over a period of 42 h and as the moisture content decreased there was a significant increase in the work to peel. In contrast, stems that had been dew‐retted in the field showed a significant decrease in work to peel. When the moisture content of stems dried in the oven decreased below 12%, the work to peel rapidly decreased.

As the plant tissues dehydrated their fracture characteristics changed and this was reflected in the increase in the work to peel seen in the oven‐dried samples. This, however, was not evident in the field‐retted samples, in which there was a decrease in work to peel. The field‐retted samples were exposed to the activity of micro‐organisms for a prolonged period of time compared with the oven‐dried samples; this increased the potential degradation caused by microbial enzymes. Thus, the reduced work to peel in dew‐retted stems is thought to be due to the colonisation of the stem by micro‐organisms and the subsequent retting process. The dramatic decrease in work to peel at low moisture content in the oven‐dried stems is thought to result from mechanical changes leading to brittle fracture characteristics.

This study indicates that peel tests can be used to objectively monitor the reduction in work to peel for dew‐retted stems and relate this reduction to the progress of retting. Thus, peel tests may be used to monitor the effects of different factors on the process of retting in hemp.
Soil fumigation and oxamyl drip applications for nematode and insect control in vegetable plasticulture
Authors: DESAEGER J , CSINOS A , TIMPER P , HAMMES G , SEEBOLD K
Published: July 2006

A series of experiments were conducted to evaluate the effect of oxamyl in combination with the soil fumigants 1,3‐D, metam sodium and methyl bromide on nematode damage and fruit yield in vegetables. Experiments were conducted in Tifton, GA, USA over five seasons, between 2000 and 2002, using four different vegetables: squash (Cucurbita pepo), cucumber (Cucumis sativus), pepper (Capsicum annuum) and eggplant (Solanum melongend). In the eggplant experiment, insect populations were monitored. Soil fumigation alone, irrespective of application method or formulation, gave acceptable control of root‐knot nematode in all experiments, except in the spring 2001 pepper experiment. Oxamyl by itself did not provide control of root‐knot nematode (Meloidogyne incognita), but insect populations on eggplant were reduced. Out of three experiments that included oxamyl by itself, root galling caused by Meloidogyne spp. was reduced only on eggplant when nematode pressure was low (five nematodes per 150 cm3 soil). When oxamyl was applied in combination with pre‐plant soil fumigation, small but consistent reductions in root galling were observed. Greatest reductions in galling due to oxamyl were found when fumigation provided less than optimal nematode control. The timing of application of oxamyl did not have much impact on nematode infection, but applications early in the season, preferably starting at planting, appear to be beneficial. Stubby root nematode (Paratrichodorus spp.) populations were low and variable in most experiments, but neither fumigation nor post‐plant nematicide applications seemed to have any effect on soil populations at harvest. Crop yields were often significantly greater when oxamyl followed fumigation, as compared to fumigation only, which could be due to a reduction in root‐knot nematode damage (and in the case of eggplant also reduced foliar damage by insects), and/or to a carbamate growth stimulant response. These experiments indicate the potential of oxamyl to reduce root‐knot nematode infection and increase yields of vegetables when combined with soil fumigation by 1,3‐D and/or metam sodium. More research is required to understand the effect of crop type, pest pressure, preceding fumigant (1,3‐D or metam sodium) and injection timing of oxamyl.
Relationship between canopy reflectance and yield loss due to disease in barley
Authors: NEWTON A C , HACKETT C A , LOWE R , WALE S J
Published: July 2006

Reflectance from barley field trial plots was measured to determine whether it could be used as an accurate estimate of disease and yield response to fungicide, and whether this was consistent over a range of agronomic factors. Three trials were used to test the effects of cultivar, assessment date, fungicide and dose, different disease and fertiliser. Correlations with predominant disease and resulting yield loss were high, often better than visual disease or green leaf area measurements alone. Certain ratios of two reflectance wavelength measurements were more robust predictors than single wavelengths. Cultivar and development stage had a large influence on measurements and calibration for such morphology‐based characters would be essential for practical deployment. Whilst weather conditions and solar angle restrict opportunities for usage of reflectance tools such as the‘Cropscan Radiometer', it may prove useful in crop loss assessments as an additional objective tool.
The cassava mosaic geminiviruses occurring in Uganda following the 1990s epidemic of severe cassava mosaic disease
Authors: SSERUWAGI P , REY M E C , BROWN J K , LEGG J P
Published: July 2006

The cassava mosaic geminiviruses (CMGs) isolated from cassava plants expressing mild and severe symptoms of cassava mosaic disease (CMD) in 2002 in Uganda were investigated using the polymerase chain reaction and restriction fragment length polymorphism (PCR‐RFLP) molecular techniques and DNA sequencing. Two previously described cassava mosaic geminiviruses: African cassava mosaic virus (ACMV) said East African cassava mosaic virus ‐ Uganda variant (EACMV‐UG2) were detected in Uganda. The RFLP technique distinguished two polymorphic variants of ACMV (ACMV‐UG1 and ACMV‐UG2) and three of EACMV‐UG2 (EACMV‐UG2[1], EACMV‐UG2[2] and EACMV‐UG2[3]). ACMV‐UG1 produced the fragments predicted for the published sequences of ACMV‐[KE]/UGMld/ UGSvr, while ACMV‐UG2, which produced the RFLP fragments predicted for the West African ACMV isolates ACMV‐[NG], ACMV‐[CM], ACMV‐[CM/DO2] and ACMV‐[CI], was shown to be ACMV‐UGMld/UGSvr after DNA sequencing. EACMV‐UG2[1] produced the RFLP fragments predicted for the published sequences of EACMV‐UG2/UG2Mld/UG2Svr. However, both EACMV‐UG2[2] and EACMV‐UG2[3], which produced East African cassava mosaic vzras‐[Tanzania]‐like polymorphic fragments with RFLP analysis, were confirmed to be isolates of EACMV‐UG2 after DNA sequencing. Thus, this study emphasises the importance of DNA sequence analysis for the identification of CMG isolates. EACMV‐UG2 was the predominant virus and occurred in all the surveyed regions. It was detected in 73% of the severely and 53% of the mildly diseased plants, while ACMV was less widespread and occurred most frequently in the mildly diseased plants (in 27% of these plants). Mixed infections of ACMV and EACMV‐UG2 were detected in only 18% of the field samples. Unlike previously reported results the mixed infection occurred almost equally in plants exhibiting mild or severe disease symptoms (21% and 16%, respectively). The increasing frequency of mild forms of EACMV‐UG2 together with the continued occurrence of severe forms in the field warrants further studies of virus‐virus and virus‐host interactions.
Relationship between water‐soluble Ca and other elements and bitter pit occurrence in ‘Idared’ apples: a multivariate approach
Authors: PAVICIC NIKOLA , JEMRIC TOMISLAV , KURTANJEK ZELIMIR , COSIC TOMISLAV , PAVLOVIC IVO , BLASKOVIC DRAZEN
Published: July 2006

The mineral composition of sound fruits of Idared apple and those with symptoms of bitter pit was investigated at two sites on M9 rootstock (Sites 1 and 2) and two sites on MM 106 rootstock (Sites 3 and 4). Concentrations of N, P, K, Ca and Mg were measured. Mg and Ca concentration were determined in water soluble (WS) and water‐insoluble (WI) fractions. The sum of these fractions was regarded as the total concentration (T). At all four sites, Ca (WS) was significantly higher in sound fruit. Principal component analysis (PCA) of data from individual locations showed that the first PCA component accounted for a high proportion of total variance (85% and 70% for Sites 1 and 2 and 70% and 69% for Sites 3 and 4, respectively). Projections of the samples into the planes of the first two PCA components revealed exact classification of the bitter pit status for all samples. The projections revealed that the first PCA component was essential for classification of the status. Determination of the distribution of components of the first PCA indicated that deficiency of water soluble Ca was the most significant factor related to development of bitter pit in ‘Idared’ apples.
Analysing spatial patterns of spread of Lettuce necrotic yellows virus and lettuce big‐vein disease in lettuce field plantings
Authors: COUTTS B A , THOMAS‐CARROLL M L , JONES R A C
Published: July 2006

Spatial patterns of spread of lettuce big‐vein disease (LBVD) and Lettuce necrotic yellows virus (LNYV) were examined in two plantings each consisting of two blocks of lettuce. LBVD came from planting land infested with viruliferous Olpidium brassicae resting spores, while LNYV was introduced by aphid vectors from external sources consisting of LNYV‐infected sowthistle (Sonchus oleraceus) weeds. Clustering of LBVD was obvious in an area where the soil was heavily infested with only sporadic occurrence elsewhere. There was a steep decline in LNYV incidence over distance from a concentrated external weed source, with clustering of LNYV‐infected plants at the crop edge closest to it. There was no evidence of secondary spread with LBVD or LNYV.
Response of Acroptilon repens to simulated herbivory and soil disturbance
Authors: Kolören O. , Uygur S. , Uygur F.N. , Schaffner U.
Published: July 2006

Acroptilon repens is an invasive weed in North America but also causes problems in disturbed habitats in its native range in Asia. In order to test the effect of simulated biological control and soil disturbance on established A. repens patches and the competing vegetation, two levels of shoot clipping as well as soil tillage were imposed on A. repens patches in an undisturbed meadow and at two fallowland sites in the native range of the weed. At the meadow site, 2 years of partial clipping of shoots and of soil tillage had no influence on A. repens performance, while soil tillage significantly reduced the above‐ground biomass of the competing vegetation. At the fallowland sites, which had been continuously cultivated for several years prior to the experiment, A. repens shoot density, biomass and number of seed heads were significantly higher in the undisturbed control than in the tillage plots. The total number of seed heads per unit area increased with shoot density up to 200 shoots m−2. These results indicate that A. repens has considerable regrowth capacities that allow established patches to tolerate substantial losses of above‐ground biomass and that the competitive ability of A. repens is favoured both when soil disturbance is imposed on previously undisturbed sites, as well as when repeated soil disturbance is abandoned. The only promising nonchemical herbicide‐based approach to reduce the competitive ability and seed output of A. repens appears to be a long‐term management that enhances the interspecific plant competition by reducing soil disturbance and selectively damaging A. repens.
Resistance to Tobacco mosaic virus and Botrytis cinerea in tobacco transformed with complementary DNA encoding an inhibitor of viral replication‐like protein
Authors: Akad A. , Teverovsky E. , Gidoni Elad D., Y. , Kirshner B. , Rav‐David D. , Czosnek H. , Loebenstein G.
Published: July 2006

We have previously cloned a 1016‐bp‐long complementary DNA (cDNA) clone (named NC330) encoding an inhibitor of virus replication (IVR)‐like protein from induced‐resistant leaves of Nicotiana tabacum cv. Samsun NN. In the present work, NC330 cDNA was cloned in an Agrobacterium binary vector and introduced into the genome of N. tabacum cv. Samsun nn that is susceptible to Tobacco mosaic virus (TMV). Eight R0 were highly resistant, with TMV titres less than 2% of the controls. The progeny of these primary transformants resulted in four TMV‐resistant and four susceptible lines. The progeny of the plant with highest resistance for TMV was selfed during four generations. In the R2 generation, out of 112 plants tested, 3 plants showed excellent resistance and 5 a lesser degree of resistance. NC330 transcripts were detected in these R2 plants as well as in their R1 and R0 parents. Two R2 plants were self‐pollinated to obtain the R3 generation. All the 25 R3 progeny plants of one line contained PCR‐amplifiable NC330, compared with only 6 of the 23 progeny plants from the other line. Following TMV inoculation, virus was undetectable in seven of the eight tested R3 progeny of the first line and five of the six R3 progeny plants of the second line. NC330 transcripts were detected in the TMV‐resistant transgenic plants but also in some susceptible plants. TMV resistance was suppressed when the plants were kept at higher temperatures (32–34°C), whereas returning the plants to lower temperatures (24–26°C) restored resistance. Transgenic plants resistant to TMV were also resistant to B. cinerea following inoculation of seedlings or of whole plants. The presence of the NC330 DNA was correlated with changes in the physiology of the transgenic plant. Seed germination was inhibited at high temperatures and in the dark. Rootlets of germinating seeds of the transgenic plants grew significantly faster than those of control seeds. These observations were correlated with a significantly higher concentration of abscisic acid in the seeds and seedlings of the transgenic plants. In silico analysis suggests that the NC330 protein translated from the NC330 cDNA is a tetratricopeptide repeats protein and that it may be involved in protein–protein interaction as part of the pathogen resistance mechanism.
Modelling the effect of soil moisture on germination and emergence of wheat and sugar beet with the minimum number of parameters
Authors: Rinaldi M. , Di Paolo E. , Richter G.M. , Payne R.W.
Published: July 2006

Soil moisture and temperature, sowing depth and penetration resistance affect the time and percentage of seedling emergence, which are crucial for the simulation of drought‐limited crop production. The aim of this research was to measure the effect of soil water potential on germination and emergence, shoot and root elongation rates (SER and RER) of two different seed/crop types. Sugar beet and durum wheat seeds were sown into two soils (clay and loam), submitted to five matric potentials (−0.01, −0.1, −0.2, −0.4 and −0.8 MPa) and incubated at constant temperature (25°C) and humidity. Cumulative count analysis was used to estimate parameters of the distribution of germination or emergence times for each box of beet or wheat seeds and to derive estimates for base potentials (ψb), hydrothermal times (H) and numbers of viable units. In a second experiment, NaCl solution was used to mimic the soil matric potentials to estimate potential RER and SER. Germination of sugar beet was slightly more sensitive to matric potential than durum wheat (ψb of −1.13 and −1.23 MPa, respectively). H(g) was longer for sugar beet than for durum wheat (67 vs 47 MPa °Cd). For emergence ψb was similar for both seed types and soils but hydrothermal times (H(e)) were 40 MPa °Cd higher for sugar beet than for wheat. Emergence was about 20 MPa °Cd earlier in loam than in clay. SER measured in soils were similar for both crops and for durum wheat it agreed with those determined in NaCl solution. RER and SER fell with decreasing osmotic potential to approximately 20% of their maximum values (1.03 mm h−1 and 0.57 mm h−1, respectively). Seedling viability decreased with decreasing matric potential and more in clay than in loam soil and more for sugar beet than durum wheat. Seed and soil aggregate size are discussed with respect to the effects of water diffusion and soil–seed contact on germination and emergence modelling.
The Five Aspects Meal Model: a tool for developing meal services in restaurants
Authors: Gustafsson Inga‐Britt , Öström Åsa , Johansson Jesper , Mossberg Lena
Published: July 2006

Preparing, planning and serving meals require several important steps before you can enjoy a meal. The meal takes place in a room (room), where the consumer meets waiters and other consumers (meeting), and where dishes and drinks (products) are served. Backstage there are several rules, laws and economic and management resources (management control system) that are needed to make the meal possible and make the experience an entirety as a meal (entirety – expressing an atmosphere). These five factors are the major ones for developing meal service in restaurants, and together form the Five Aspects Meal Model (FAMM). Several studies have shown that the context of a meal is important for the acceptance and consumption of a meal. Accordingly, the context has to include the food product itself, the consumer and the environment. These three factors need to be considered in an integrated manner, because they affect each other. A qualitative study of restaurant consumers found that there are at least eight main categories of importance for the experience of the meal: restaurant atmosphere, core items of consumption, restaurant scene, personal service encounter, staff quality, visitors, restaurant decision process and individual circumstances. These categories can easily be related to the ‘Five Aspects Meal Model’. The essence of each factor is dependent upon different forms of knowledge, such as science, practical‐productive, aesthetical and ethical.
Ecological impact of application of wastewater biosolids to agricultural soil
Authors: Rogers Michael , Smith Stephen R.
Published: July 2006

There has been little investigation of the ecological interactions between major organisms brought about by the application of wastewater biosolids to agricultural soil. This paper provides an overview of the possible effects of biosolids application on these ecosystems by using what is known about the ecology and diversity of microbial populations in soil and biosolids. Areas considered include interactions between indigenous and introduced bacterial populations, impacts of biosolids application on soil protozoa and the role of phages in bacterial population dynamics. These ecological processes are particularly relevant, for instance, to increase an understanding of the fundamental mechanisms responsible for inactivation of potentially infectious enteric microorganisms in biosolids‐amended agricultural soil.
Influence of humic substances on the ultraviolet disinfection of surface waters
Authors: Alkan Ufuk , Teksoy Arzu , Ateşli Ahu , Başkaya Hüseyin Savaş
Published: July 2006

The efficiency of ultraviolet (UV) disinfection and the regrowth potential of total coliforms were investigated in humic waters. Experiments were conducted according to an experimental design in which a UV radiation dose range of 68–681 mW s/cm2 was applied to waters containing various concentrations (0–10 mg/L) of fulvic acid. Experimental results strongly suggested that the harmful effect of UV radiation on bacteria was diminished in humic waters due to absorption of UV light. Increasing concentrations of fulvic acid appeared to enhance its influence with elevated doses of UV radiation. Measured inactivation responses were on the order of 1–6 log10 units for the UV dose range used. Comparison of k (inactivation coefficient) values for nonhumic water to highly humic water indicated that k decreased proportionally as the fulvic acid concentration of water was increased. The results of dark‐incubation tests indicated significant regrowth of bacteria in fulvic acid‐containing waters.
Integrated regulation – experiences of IPPC in England and Wales
Authors: Gray J. , James T. , Dickson J.
Published: July 2006

Environmental regulators around the world are seeking out new ways to regulate polluting industries that can deliver higher levels of environmental protection without increasing overall cost. Integrated regulation has been shown to offer many advantages over traditional single‐media approaches and this has led to its widespread uptake across the European Union (EU). The United Kingdom (UK) is seen as a leader in the field, having been progressing towards full integration for over 15 years. This paper seeks to share some of the experiences gained by the Environment Agency for England and Wales, with others struggling with the complex policy, technical and legal issues that will be encountered along the way.
Modeling of the Onset of Gas Entrainment From a Stratified Two-Phase Region Through Branches on a Curved Surface
Authors: Andaleeb A. F. , Hassan I. , Saleh W. , Ahmad T.
Published: July 2006

The present investigation is focused on the onset phenomena from a stratified two-phase region through a single branch located on a semi-circular wall, resembling a circular reservoir of a CANDU header-feeder configuration. Two different models have been developed, over the whole range of branch Froude number, to predict the critical height at the onset of gas-entrainment. The results showed that there is both a maximum and a minimum physical limit of prediction, which depends on the branch size and configuration. Also, at a distinct range of Froude numbers within the physical limits, the predicted values of both models collaborated to the same values. The critical height corresponding to the onset of gas entrainment was found to be a function of the branch orientation and Froude number. Three different experimental data sets at branch orientation angles of zero, 45, and 90 degrees were used to validate the present models. A good concurrence was illustrated between the experimental and theoretical values.
Eulerian-Eulerian Modeling of Disperse Two-Phase Flow in a Gas-Liquid Cylindrical Cyclone
Authors: Reyes-Gutiérrez Miguel A. , Rojas-Solórzano Luis R. , Marín-Moreno Juan C. , Meléndez-Ramírez Antonio J. , Colmenares José
Published: July 2006

This work presents a three-dimensional computational fluid dynamics (CFD) study of a two-phase flow field in a gas-liquid cylindrical cyclone (GLCC) using CFX4.3™, a commercial code based on the finite volume method. The numerical analysis was made for air-water mixtures at near atmospheric conditions, while both liquid and gas flow rates were changed. The two-phase flow behavior is modeled using an Eulerian-Eulerian approach, considering both phases as an interpenetrating continuum. This method computed the inter-phase phenomena by including a source term in the momentum equation to consider the drag between the liquid and gas phases. The gas phase is modeled as a bimodal bubble size distribution to allow for the presence of free- and entrapment gas, simultaneously. The results (free surface shape and liquid angular velocity) show a reasonable match with experimental data. The CFD technique here proposed demonstrates to satisfactorily reproduce angular velocities of the phases and their spatial distribution inside the GLCC. Computed results also proved to be useful in forecasting bubble and droplet trajectories, from which gas carry under (GCU) and liquid carry over might be estimated. Nevertheless, moderate differences found between the computed GCU and experimental measurements suggest that new adjustments may be done to the numerical model to improve its accuracy.
Exploring breathing pattern irregularity with projection‐based method
Authors: Ruan Dan , Fessler Jeffrey A. , Balter James M. , Sonke Jan‐Jakob
Published: July 2006

Accurate descriptions of organ motion due to breathing are highly desirable for radiation treatment planning. This paper proposes an index that quantifies the irregularity of a signal related to respiratory motion. The method works by finding the periodic band‐limited signal that best fits the signal samples, and then computing the root mean squared (RMS) residual error. The fitted signal itself may be useful for treatment planning. Using clinical data describing amplitude‐time relationships (RPM, Varian) from twelve patients, we correlated the proposed index against relevant metrics from various treatment planning schemes. Simulation results demonstrate a reasonable match with all treatment methods considered, suggesting that the proposed irregularity index is suitable for a variety of treatment methods. Compared to the modified cosine function, which was investigated previously for breathing pattern models, the proposed approach is more representative, flexible, and computationally efficient.