bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inheritance of resistance to lettuce root aphid in the lettuce cultivars ‘Avoncrisp’ and ‘Lakeland“
Authors: ELLIS P R , PINK D A C , RAMSEY A D 
Published: February 2008

SummaryThe inheritance of resistance in two lettuce cultivars to lettuce root aphid, Pemphigus bursarius, was studied in a series of laboratory and field experiments at Wellesbourne between 1989 and 1992. A source of total resistance in the cv. ‘Avoncrisp’ which is linked to the downy mildew resistance gene Dm6, was shown to be governed by a single dominant gene. There were no maternal effects evident in the inheritance of this resistance. The basis of the high level of resistance which exists in the cv. ‘Lakeland’ (formerly known as ‘Jubilee’) was also shown to be controlled by the same dominant gene. The linkage between Dm6 and root aphid resistance was broken in ‘Lakeland’ as this cultivar does not possess the Dm6 gene. The linkage was presumably broken when the original cross between the parents of cv. ‘Lakeland’, ‘Calmar’ and ‘Avoncrisp’ was made. Under laboratory conditions small numbers of aphids commence development on cv. ‘Lakeland’ but colonies fail to develop and under field conditions the resistance provides adequate Protectión against the pest. The resistance in both ‘Avoncrisp’ and ‘Lakeland’ was effective against a population of lettuce root aphid collected from an endive crop in southern France as well as being effective against the Wellesbourne population of this aphid.
Interactions between a seed‐borne strain of cucumber mosaic cucumovirus and its lupin host
Authors: GEERING A D W , RANDLES J W 
Published: February 2008

SummaryThe relationship between time of inoculation with cucumber mosaic cucumovirus (CMV) and the growth, seed production and rate of seed transmission of virus in lupin (Lupinus angustifolius cv. Illyarrie) was studied in field‐grown plants. Plants inoculated at the seedling stage (2 days post‐emergence) showed 45% mortality. Plants infected through the seed were more stunted than plants inoculated at the seedling stage. Plants inoculated up to the mid‐vegetative growth stage (58 days post‐emergence) yielded ≤ 27% of the dry matter and ≤ 9% of the seed of healthy plants. Late inoculation (114 days post‐emergence) did not affect dry matter yield, but reduced seed yield to 75% of that of healthy plants. Rate of seed transmission depended on the time of inoculation of plants. The maximum rate was 24.5% for plants that were inoculated at the mid‐vegetative growth stage (58 days post‐emergence). However, early inoculation caused a large reduction in seed yield, and it was shown that plants inoculated at the beginning of flowering (94 days post‐emergence) produced greater numbers of infected progeny than plants inoculated at earlier or later times. No relationship was observed between seed weight and transmission of CMV. Infectious CMV was recovered from the embryo, but not from the testa.A simple seed transmission model was used to evaluate several hypothetical epidemics and to determine the time of inoculation which results in greatest rates of seed transmission of CMV. For example, when fewer than 73% of plants in a crop become infected with CMV, then the rate of transmission of virus in crop seeds will be greatest when inoculations are at the beginning of flowering.
Field resistance in maize cultivars to stem borer Chilo partellus
Authors: KUMAR HARISH 
Published: February 2008

SummaryThe Kenyan maize varieties, Hybrid 511, Hybrid 622, Pwani hybrid, Katumani Composite B, and local populations were evaluated along with the varieties of Multiple Insect‐Resistant Tropical (MIRT) pool and experimental varieties from The Maize and Wheat Improvement Centre (CIMMYT), Mexico for resistance to the stem borer, Chilo partellus (Swinhoe). The artificial infestation by first‐generation C. partellus on maize during the early whorl stage revealed that the leaf feeding damage, the dead heart formation, and the stem damage on the Kenyan hybrids and populations were significantly greater than on the MIRT varieties. The experimental varieties of CIMMYT were also susceptible to C. partellus. When the maize was infested at anthesis, the Kenyan varieties displayed a moderate level of resistance in terms of stem tunnelling and grain damage by C. partellus. The varieties of Multiple Insect Resistance Tropical pool can be effectively used by the breeders to enhance the resistance of agronomically good, but susceptible, varieties of Kenya.
Breeding for partial resistance in dry beans (Phaseolus vulgaris) to bean rust (Uromyces appendiculatus)
Authors: EDINGTON B R , SHANAHAN P E , RIJKENBERG F H J 
Published: February 2008

SummarySignificant differences in susceptibility of 23 bean cultivars were found after natural infection by a single‐pustule isolate of bean rust in field trials over three seasons. These differences were not related to differences in the number of adaxial or abaxial acicular leaf hairs, latent period in primary leaves or a difference in pustule size. Forty‐five large‐seeded bean lines with partial resistance to a single‐pustule isolate were developed by recurrent selection for commercial evaluation.
Antixenosis component of resistance to sorghum midge, Contarinia sorghicola Coq. in Sorghum bicolor (L.) Moench
Authors: SHARMA H C , VIDYASAGAR P 
Published: February 2008

SummarySorghum midge, Contarinia sorghicola Coq. (Diptera: Cecidomyiidae) is the most destructive pest of grain sorghum, and host‐plant resistance is an effective method of controlling this insect. We studied the antixenosis component of resistance to sorghum midge using multi‐, double‐ and no‐choice cage tests, and under multi‐choice field conditions to quantify and understand the nature of antixenosis component of resistance to this insect in Sorghum bicolor (L.) Moench. Midge response towards sorghum panicles was influenced by panicle size and cage type used to study the orientation behaviour. Maximum number of midges were recorded at 30 and 60 min after initiating the experiment. Antixenosis shown by C. sorghicola under multi‐choice field conditions to ICSV 197 and TAM 2566 was not confirmed under cage tests, while DJ 6514, AF 28 and IS 3461 were non‐preferred both under field and cage conditions. Midge‐resistant female parents (PM 7061 and PM 7068) were less preferred than the midge susceptible (ICSA 42 and 296A) female parents. Male‐sterility did not influence host finding and acceptance by the midge females, although in one out of two tests, the maintainer lines (B‐lines) were preferred over the male‐sterile lines (A‐lines).
Glasshouse‐based selection to identify agronomically adapted, uniform true potato seed (TPS) progenies
Authors: CLULOW S A , BRADSHAW J E 
Published: February 2008

SummaryTwenty‐five true potato seed progenies and five clonally maintained cultivars were grown in a glasshouse. Tubers of each clone of each progeny were grown in a field experiment. At harvest, one seed tuber was taken from each plant and field grown for a second year. After each experiment, the tubers from every plant were weighed and counted and their colour, shape, form (regularity) and skin finish assessed. Progeny means and variances for each character were calculated. There were significant differences between means for each character in all experiments, except mean yield in the glasshouse, variances for each character in both field experiments and tuber number variances and colour variances in the glasshouse. In general, Pearson's product‐moment correlations between glasshouse and field assessments were moderate or poor (r ≤ 0.6) and inconsistent between experiments. Spearman's rank correlations between glasshouse and field assessments for progeny means were similar to the linear correlations, while those for variances were somewhat better. Rank correlation gave more consistent results between experiments. Ranking glasshouse means will allow some worthwhile progeny selection for tuber colour, shape and skin finish. It can be a useful screen for progenies with the highest levels of uniformity for all characters.
Effect of light on DIMBOA‐glucoside concentration in wheat {Triticum aestivum L.)
Authors: ÅHMAN I , JOHANSSON M 
Published: February 2008

SummaryDIMBOA (2,4‐dihydroxy‐7‐methoxy‐1,4‐benzoxazin‐3‐one) glucoside in wheat has been suggested to play a role in plant resistance to cereal aphids. Thus there is considerable interest in trying to breed modern wheat varieties with increased concentrations of this compound. To further such work we assessed the effects of light intensity on DIMBOA glucoside production in wheat seedlings under both indoor and outdoor conditions. Light had a marked effect on DIMBOA‐glucoside concentrations, with levels in plants being negatively related to light intensity. Our findings suggest that breeding aimed at increasing levels of DIMBOA‐glucoside would be most effective if test plants for selection were to be grown under weak light conditions.
Properties of cocksfoot streak and cocksfoot cryptic, two viruses infecting cocksfoot (Dactylis glomerate) in Scotland
Authors: TORRANCE LESLEY , JONES A T , DUNCAN G H 
Published: February 2008

SummaryA Scottish isolate of cocksfoot streak virus (CSV‐S) was found to have flexuous filamentous particles which, in sap of infected cocksfoot plants, had a modal length of 712 nm. It was transmitted from infected to healthy cocksfoot plants in a non‐persistent manner by Myzus persicae and by mechanical inoculation of infective sap extracts containing an anti‐oxidant. Apart from cocksfoot, mechanical inoculation of infective sap succeeded in infecting only four of 22 plant species tested. The infectivity of sap extracts containing 0.2% thioglycerol was lost after heating for 10 min at 55oC but not 50oC, storage at room temperature for 48 but not 24 hours, and after diluting 10‐2 to 10‐3. Highly purified preparations of CSV‐S particles sedimented as a single component with a sedimentation coefficient of 139S and had a buoyant density in rubidium bromide of 1.31 g/cm3. Virus particles were composed of one protein and one ssRNA species with estimated Mr of 31 000 and 3.2 times 106 respectively. In ELISA, an antiserum prepared to CSV‐S detected the virus in all aerial parts of infected cocksfoot plants and, when present in the ratio of 1 infected leaf: 1000 healthy leaves. Both CSV‐S‐infected and ‐uninfected cocksfoot also contained a previously undescribed virus with isometric particles c. 30 nm in diameter. This virus, named cocksfoot cryptic virus (CCV), was seed‐borne in two cvs of cocksfoot tested and its particles contained two dsRNA species of estimated Mt of 1.14 times 106 and 1.27 times 106. Despite the fact that particles of CSV‐S were largely free from CCV particles following exclusion chromatography on agarose beads prior to immunisation, immunoelectron microscopy (IEM) showed that the antiserum prepared to CSV‐S also contained some antibodies to CCV. Evidence from IEM suggested a possible distant serological relationship of CCV to ryegrass and beet (BCV 1 or BCV 2, or both) cryptoviruses, all members of sub‐group A of cryptoviruses.
A comparison of the flora and arthropod fauna of organically and conventionally grown winter wheat in southern England
Authors: MOREBY S J , AEBISCHER N J , SOUTHWAY S E , SOTHERTON N W 
Published: February 2008

SummaryFields of winter wheat on organic and conventional farms were sampled for weeds and invertebrates in June/July in 1990 and 1991. Organic fields were paired with adjoining conventional ones and their invertebrate fauna compared with a D‐vac vacuum suction sampler. Weed counts showed greater percentage cover of broad‐leaved weeds in organic fields than in conventional ones, with three times as many species present where herbicides were not used.Significantly higher densities of nematoceran and acalypteran Diptera, Hem‐iptera (especially aphids), aphid‐specific predators, parasitic Hymenoptera and cryptophagid and cantharid Coleoptera were found in conventionally grown fields. Significantly higher densities of weevils, spiders, springtails, plant hoppers and sawfly larvae were found in organic fields. Reasons for these differences or the lack of them are discussed.
Serological characterisation of citrus tristeza virus isolates from Israel
Authors: SHALITIN D , MAWASSI M , GAFNY R , LEITNER O , CABILLY S , ESHHAR Z , BAR‐JOSEPH M 
Published: February 2008

SummarySeven monoclonal antibodies (MAbs) showing homologous reactions with the VT strain of citrus tristeza virus (CTV) were tested against 21 CTV strains or isolates, representing the range of biological diversity and the geographical distribution of CTV in Israel. All the CTV strains gave positive reactions in ELISA with polyclonal antibodies and with one MAb (#25#2). Two MAbs; #13#21 and #3/7 reacted with 19 and 12 out of the 21 CTV strains, respectively. Seventeen CTV strains, including all those previously assigned by sequencing their coat protein gene (CPG) to the CPG‐VT group (Mawassi, Gafny & Bar‐Joseph, 1993), reacted with five or more MAbs. Four CTV strains of minor epidemiological importance, including two members of the CPG‐MT group, did not react with five or more of the MAbs.These results indicated the existence of two serogroups of Israeli CTV strains that can be differentiated by MAbs and which closely correlate with and extend the previous CPG grouping. The extensive biological variation within each CPG group confirms recent analyses suggesting that the CTV pathogenic traits are not necessarily associated with a sequence or antigenic variation of the CTV‐CPG.
Serological relationships among rice yellow mottle virus isolates
Authors: MANSOUR A N , BAILLIS K W 
Published: February 2008

SummarySerological studies on five isolates of RYMV collected from the Ivory Coast (IC), Sierra‐Leone (SL), Niger (Nr), Kenya (K) and Nigeria (N) indicated that these isolates are serologically related. Gel double diffusion and direct ELISA tests showed that the five isolates could be arranged into three serological groups here designated RYMV‐N, SL‐IC and K‐NR. However, the ISEM studies did not reveal any clear grouping of the heterologous isolates tested.
The effects of temperature on the availability and acquisition of potato leafroll luteovirus by Myzus persicae
Authors: SYLLER J 
Published: February 2008

SummaryThe concentration of potato leafroll luteovirus (PLRV) did not differ in potato plants with secondary infections grown at 15°C or 27°C. Detached leaves of plants grown at 15°C or 27°C were used as sources of PLRV for peach‐potato aphids (Myzus persicae Sulz.) both at 15°C and 27°C. At comparable temperature during virus acquisition, aphids which fed on leaves of plants kept previously at 15°C contained more viral antigen detected by ELISA than aphids which fed on leaves of plants grown at 27°C. The aphids which acquired PLRV at 27°C contained evidently more viral antigen than those which acquired PLRV at 15°C. The greatest amount of PLRV was found in the aphids which acquired the virus at 27°C from the leaves of plants kept at 15°C. The ability of M. persicae to transmit PLRV to Physalis ftoridana Rydb. generally decreased with decrease in the amount of PLRV in vectors.
The freezing characteristics of cauliflower curd
Authors: FULLER M P , WHITE G G , CHARMAN A 
Published: February 2008

SummaryCultivar differences in frost resistance and the heritable nature of resistance were demonstrated using seedling cauliflower plants. Such cultivar differences were not however expressed in the curd. Selection for frost resistance in cauliflower should therefore use whole plant screening techniques.Curd material when frozen as isolated florets, supercooled over the range – 1°C to – 12°C and the mean freezing point of all curds tested was ‐6°C to ‐7.25°C (overall mean ‐6.44°C). Curd florets which supercooled but did not freeze were completely undamaged, whereas freezing always led to cell damage and death observed as water‐soaking of the floret surface and measured using an electrical conductivity method. The large range of freezing points measured suggests a range of active ice nucleators either on or within the florets. When curds were frozen intact the ability of florets to supercool was severely restricted which was attributed to the seeding of freezing by the internal growth of ice crystals. A crop protection strategy needs to identify and control or modify warm temperature nucleators in cauliflower curd.
Bio‐activity of marine cyanobacteria in the animal‐based systems: Modulation of food intake, body weight and some haematological characters
Authors: SUNDARARAMAN M , AVERAL H I , AKBARSHA M A , SUBRAMANIAN G 
Published: February 2008

SummaryWith a view to assess the bioactive potential of the unexploited marine cyanobacteria available in abundance in the marine habitat, water‐soluble fraction of the ethanolic extract of 12 different strains of marine cyanobacteria were administered to male rats and their impact on food intake, body weight and certain haematological characters including RBC counts, WBC‐TC and DC, platelet counts, haemoglobin content and mean corpuscular haemoglobin was studied. The results suggest prospective applications as feed/nutritional supplements; among them, Spirulina subsalsa BDU 30311, Oscillatoria salina BDU 10142 and Phormidium valderianum BDU 20571 appear highly promising in this regard. Lyngbya sp. BDU 30601 and Pseudanabaena schmidlei BDU 30313 appear to contain one or more toxins and deter food intake and cause decrease in body weight. With Synechococcus elongatus BDU 30312 food intake increased over the control which was not commensurate with the change in body weight. The results relating to the haematological characters indicate bioactivity of the cyanobacteria in the animal‐based systems, some of which are positive, whereas a few strains like Lyngbya BDU 30601 are negative, implying their pharmaceutical application.
Resistance in sorghum to shoot fly Atherigona soccata: Evidence for the source of leaf surface wetness
Authors: SIVARAMAKRISHNAN S , SOMAN P , NWANZE K F , REDDY Y V R , BUTLER D R 
Published: February 2008

SummaryLeaf surface wetness (LSW) of the central whorl leaf of sorghum seedlings has been associated with susceptibility to shoot fly. Previous physical and physiological evidence suggested that LSW originates from the plant. This was confirmed by radioactive labelling methods using tritium and carbon‐14. Tritiated water applied to the soil of potted seedlings was translocated to the surface of the whorl leaf. There were significant differences in the amount of tritiated water collected from susceptible (CSH 5) and resistant (IS 18551) genotypes. Studies with carbon‐14 labelling of sorghum seedlings indicated the presence of (small amounts of) solutes in the surface water that may affect larval movement and survival.
Development and reproductive potential of the cereal aphid Sitobion avenae on resistant wheat lines (Triticum monococcum)
Authors: CAILLAUD CLAUDIA M , DEDRYVER C A , SIMON J C 
Published: February 2008

SummaryThe effect of wheat resistance in lines of Triticum monococcum L., on the reproductive performances of the cereal aphid (Sitobion avenae F.) was investigated. Aphids were reared from birth to adult moult either on resistant or susceptible wheat lines, and transferred as apterae to both host genotypes. The influence of these transfers on the subsequent adult weight, gonad status and reproductive performances was evaluated.Aphids transferred from resistant to susceptible plants proved able to compensate for their poor nymphal growth, mainly through additional embryo growth and an increase in the number of matured embryos within the first 10 days of their adult life. Most aphids transferred from susceptible to resistant plants died within the first week following the transfer. Their most advanced embryos matured and were born, but subsequent embryo growth was quickly reduced.The reproductive strategies adopted by S. avenae when facing plant resistance, and the hypothesis of a resistant mechanism based on a poor nutritional state of the resistant plants are discussed.
Biochemical characterisation of Pythium spp. involved in cavity spot of carrots in France
Authors: GUÉRIN LUCIA , BRIARD MATHILDE , ROUXEL FRANCIS 
Published: February 2008

SummaryThe pathogenicity and growth rate in vivo were assessed on 27 isolates of Pythium spp. recovered from cavity spot lesions on carrots grown in various parts of northwest France. Polyacrylamide gel electrophoresis of isoesterases was used to identify the Pythium spp. involved.Slow‐growing isolates were more aggressive than fast‐growing ones when inoculated on carrot tap roots. Isoesterase patterns identified the slow‐growing isolates as P. violae and P. sulcatum; P. ultimum and P. intermedium were identified among the less aggressive fast‐growing isolate group, in which some isolates were also classed as P. sylvaticum or P. irregulare, which have similar electrophoretic profiles.The incidence of Pythium spp. associated with the disease in France is discussed in regard to cavity spot in other countries.
Sources of crown rot (Phytophthora cactorum) infection in strawberry and the effect of cold storage on susceptibility to the disease
Authors: PETTITT T R , PEGG G F 
Published: February 2008

SummaryCold‐stored plants of strawberry cultivars Tamella, Cambridge Favourite and Redgauntlet were more susceptible to pathogenic isolates of Phytophthora cactorum than similar plants which had not been cold‐stored. Indigenous nonpathogenic isolates of P. cactorum did not cause crown rot in cold‐stored plants, although a small number of symptomless latent infections occurred. The majority of P. cactorum isolates causing crown rot symptoms were taken from infected strawberry crowns, although two isolates from gooseberry plants, but of uncertain origin, were also pathogenic. Outbreaks of crown rot in areas with no previous history of the disease therefore probably result from the importation of non‐indigenous inoculum with planting material.Assessments of the timing of infection in relation to cold storage revealed that a high incidence of death in the cold store and chronic wilt symptoms on planting from the store resulted from initiating symptomless infections prior to cold storage. However, infection during the period immediately after cold storage resulted in rapid wilt symptoms of Phytophthora crown rot. When plated in sterile distilled water for 24 h, pieces of tissue from infected plants which had died during cold storage produced large numbers of sporangia and zoospores. This indicates that such plant material could provide a potent source of inoculum for infections in the post storage thawing environment. It is proposed that a combination of heightened host susceptibility resulting from cold storage and the presence of scatted latent infections or infected debris among the plants could result in a sudden, large scale appearance of crown rot, as sometimes is seen with cold‐stored plantings of strawberries.