A SNaPshot assay for the rapid and simple detection of known point mutations conferring resistance to ACCase‐inhibiting herbicides in Lolium spp.

Evolution of resistance to herbicides in weeds is becoming an increasing problem worldwide. To develop effective strategies for weed control, a thorough knowledge of the basis of resistance is required. Although non‐target‐site‐based resistance is widespread, target site resistance, often caused by a single nucleotide change in the gene encoding the target enzyme, is also a common factor affecting the efficacies of key herbicides. Therefore, fast and relatively simple high‐throughput screening methods to detect target site resistance mutations will represent important tools for monitoring the distribution and evolution of resistant alleles within weed populations. Here, we present a simple and quick method that can be used to simultaneously screen for up to 10 mutations from several target site resistance‐associated codons in a single reaction. As a proof of concept, this SNaPshot multiplex method was successfully applied to the genotyping of nine variable nucleotide positions in the CT domain of the chloroplastic ACCase gene from Lolium multiflorum plants from 54 populations. A total of 10 nucleotide substitutions at seven of these nine positions (namely codons 1781, 1999, 2027, 2041 2078, 2088 and 2096) are known to confer resistance to ACCase‐inhibiting herbicides. This assay has several advantages when compared with other methods currently in use in weed science. It can discriminate between different nucleotide changes at a single locus, as well as screening for SNPs from different target sites by pooling multiple PCR products within a single reaction. The method is scalable, allowing reactions to be carried out in either 96‐ or 384‐well plate formats, thus reducing work time and cost.     

Tenth international congress of plant protection,Brighton, November 1983

Abstract

Field trials were conducted to control rodent pests of wheat crop by improving bait acceptability through taste enhancers (additives). Egg shell, egg yolk, yeast, minced meat, sheep blood and chicken blood were mixed 2% by weight individually in a bait base of broken rice and wheat flour. Brodifacoum and bromadiolone bait with egg shell additive ranked first, and egg yolk second, in preference over other additive poison baits and poison bait without additive. Poison baiting yielded 93.3% and 86.7% reduction in rodent population with brodifacoum and bromadiolone (0.005% each), respectively. Three baitings, at tillering, flowering and maturity stage of the crop, gave 91.0% tiller damage reduction with brodifacoum and 86.0% with bromadiolone as compared to control (untreated). It is concluded that three poison baitings containing egg shell additive should be initiated at tillering stage followed by flowering and maturity of the wheat crop for increased yield.     

Nouveau signalement de Hypocryphalus scabricollis (Eichhoff, 1878) en Tunisie,un ravageur émergent sur figuier (Ficus carica L.)

Hypocryphalus scabricollis (Eichhoff) (Coleoptera, Curculionidae, Scolytinae) is a new pest on fig trees (Ficus carica L.). The severe damage observed on this host in Tunisia is described and illustrated. This paper describes the morphological identification of the species and gives information on the biology of the pest and initial recommendations for its control. This is a first report for Tunisia.     

Advanced lentil lines screened for resistance to <Emphasis Type="BoldItalic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="BoldItalic">lentis</Emphasis> under greenhouse and field conditions

Fusarium oxysporum f. sp. lentis is the most important pathogen of lentil plants, and most areas under lentil cultivation are reported to have a fusarium wilt disease background. The plants are infected in the seedling stage and later stages of their development. Fusarium wilt disease, which has appeared at high incidence rates during recent years, has caused sharp drops in the yield, especially in Moghan, in the northwest of Iran. Forty-five isolates of the pathogen were collected from different regions of the country with two isolates from ICARDA in the summer of 2008 and identified using Nelson’s key. The pathogenicity of the collected isolates was studied on a sensitive line (ILL 4605) under greenhouse conditions and significant differences in pathogenicity were found among them. The most pathogenic isolates from three provinces, East Azerbaijan (EA 30), Ardebil (Ar 3) and Khorasan (Kh 45), were selected and used in screening of 55 developed lines under greenhouse and field conditions. In the greenhouse, test plants were inoculated by immersing root tips in spore suspension and sowing seeds in pre-infested pot soil. Field tests were carried out in a naturally highly infested farm. At all stages, the plant response to the disease was based on the percentage of dead plants. Cluster analyses of the greenhouse and field data led to the selection of three lines (81S15, FLIP2007-42 L and FLIP2009-18 L) that were resistant under greenhouse and field conditions.     

Variability among Spanish citrus tristeza virus isolates revealed by double-stranded RNA analysis

A survey for citrus tristeza virus (CTV) strains, based on double-stranded RNA (dsRNA) analysis, was carried out in five locations on the eastern citrus-growing area of Spain. CTV was recovered from 137 trees of different ages, citrus species and varieties, sampled in 53 orchards. The best months for dsRNA recovery were April, May, September, October, and November, and the highest dsRNA yield was obtained from sweet orange cultivars. Sixteen dsRNA profiles differing by the number and/or position of subgenomic bands were detected. One of these profiles was detected in more than half the trees analysed. Maximum diversity of dsRNA patterns was found in the location with the oldest citrus orchards and the highest CTV incidence (Alzira-Carcaixent). In many instances, several dsRNA profiles were detected in neighbouring trees of the same orchard, notably in Alzira-Carcaixent, where 70% of the plots sampled contained more than one profile. The possible causes for the diversity of CTV isolates found in this specific area are discussed.     

Factors Affecting the Release of Ascospores of Anisogramma anomala

ABSTRACT Relationships between environmental factors and release of ascospores of Anisogramma anomala, the causal agent of eastern filbert blight, were examined in four European hazelnut (Corylus avellana) orchards during a 2-year period. In each orchard, Burkhard volumetric spore traps and automated weather-monitoring equipment were deployed for 12-week periods beginning at budbreak, when hazelnut becomes susceptible to infection. Ascospores of A. anomala were released when stromata on the surface of hazelnut branches were wet from rain but not from dew. Release of ascospores ceased after branch surfaces dried. The duration of free moisture on branch surfaces regulated the initiation and rate of ascospore release, but no significant effects of temperature, relative humidity, wind, or light on ascospore release were apparent. Most (>90%) ascospores were captured during precipitation events that exceeded 20 h in duration, which represented about 10% of the total precipitation events each season. Quantitative relationships between the hourly capture of A. anomala ascospores and hours since the beginning of a precipitation event were developed. With the onset of precipitation, the hourly rate of ascospore capture increased until the fifth hour of rain, remained relatively constant between the fifth and twelfth hours, and then declined gradually. During the 12-week spore-trapping periods, the likelihood and rates of ascospore release associated with precipitation were highest at budbreak and then declined through April and May until early June, when the reserve of ascospores in the perithecia was depleted. Large numbers of ascospores were captured in the volumetric spore traps, indicating that ascospores may be commonly dispersed long distances on air currents as well as locally by splash dispersal within the canopy, as reported previously. The results indicate that monitoring seasonal precipitation patterns may be useful for estimating the quantity and temporal distribution of airborne inoculum during the period that the host is susceptible to infection.     

Temperature-dependent development rates of <Emphasis Type="Italic">Bracon vulgaris,</Emphasis> a parasitoid of boll weevil

The duration of development of Bracon vulgaris Ashmead, parasitoid of the boll weevil Anthonomus grandis Boheman, was determined at nine constant temperatures between 18°C and 38°C. Nonlinear regression analysis was used to test the fit of temperature-dependent development rates to the Sharpe and DeMichele and Lactin et al. models. At the highest tested temperature (38°C) all the parasitoid eggs died before hatching and no evidence of development was observed. The high values of R ² for the models of Sharpe and DeMichele (0.8432 to 0.9834), and Lactin et al. (0.9071 to 0.9795) indicated that these models are suitable to estimate the development rate of B. vulgaris as a function of temperature. B. vulgaris showed tolerance to high temperature which is represented by the high value of H _H (change in enthalpy associated with high-temperature inactivation of the enzyme) for the prepupa stage of this insect obtained with the Sharpe and DeMichele model. According to that model, B. vulgaris exhibits thermal stress at 35.7°C, which indicates that maximum thermal stress estimated by this model was close to the real one.     

春小麦碳同位素分辨率与相关生理性状的遗传相关分析

用17份春小麦品种作为试验材料,在宁夏灌区银川测定碳同位素分辨率(△)、水分利用效率 (WUE)、灰分、比叶重、光合气体交换参数,并在方差分析显著的基础上,进行遗传、表型和环境相关分析和简单相关分析.结果表明:各性状在品种间存在显著或极显著差异 .△Gm与Sm、WUE、maL、 Ci、Gs、Ci/Ca均呈极显著正遗传相关,与开花期Pn及灌浆期Tl呈显著负遗传相关;△S m与WUE、maL、开花期气体交换参数(Ci、Gs、Ci/Ca)的遗传相关性达到极显著正相关水平,与Tl、开花期Pn的遗传相关达到极显著负相关水平,并且它们之间的遗传相关主要受遗传基因的控制,环境条件对其相关性影响较小,maL与△的显著的遗传相关,作为△的替代指标有较大的潜力,认为在灌区适合种植和培育高秆型、高碳同位素分辨率型和低温型小麦.