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1.
An extensive survey of wheat cultivars showed a complete association between the presence of a granule bound starch synthase (GBSS-4A) null mutation and the classification of the respective cultivar into the white salted noodle category. Since flour swelling volume (FSV) is a standard assay of flour used to identify cultivars that have potential for the production of white salted noodles, the results of the survey were investigated further by studying the genetic association of GBSS-4A null genotypes and FSV. A study of 34, F2 derived families, from a cross between wheat cultivars Reeves (good noodle texture, high FSV) and Kulin (poor noodle texture, low FSV), provided clear evidence for the genetic association of a granule bound starch synthase (GBSS-4A) null mutation and FSV. The molecular basis for the affect of the GBSS-4A null mutation was not simply due to a decrease in amylose content in the starch granules. Instead, the null mutation most likely causes a subtle change in starch structure as indicated by the association of high starch viscosity with high FSV and the GBSS-4A null genotype. The study suggests that assaying for the GBSS-4A null mutation at the DNA level may provide a valuable screen for noodle quality at early stages in a breeding program aimed at good white salted noodle quality.  相似文献   

2.
The field toxicity of three chemical locust control agents to terrestrial non-target arthropods was investigated in small- and large-scale field trails in the recession area of the migratory locust, Locusta migratoria capito (Sauss.) (Orthoptera: Acrididae), in Southwestern Madagascar. The insecticides were applied as full cover sprays on 16 ha (1994) and 400 ha (1995) plots, respectively. The relative abundance of more than 40 arthropod taxa (combined 1994 and 1995 trials) was monitored during 4 weeks before and at least 12 weeks after treatment. The organophosphate fenitrothion (F, 1994) caused significant medium to long-term population declines of >75% in several epigeal non-target insect taxa (springtails, ants, Zophosis madagascariensis Deyrolle (Coleoptera: Tenebrionidae)) and was classified as a high risk product. Non-target grasshoppers were reduced by about 50–60%. Springtail relative abundance returned to pre-spray levels in the following season. Significant effects of the organophosphate–pyrethroid combination fenitrothion–esfenvalerate (FE, 1995) were usually <75% (medium risk). However, springtails responded as sensitive to this product as to fenitrothion, and there were no indications of recovery over the 12 week post-treatment observation period. The insect growth regulator (IGR) triflumuron (TFM, 1994 and 1995) posed a low risk to ground-dwelling insects except for orthopterans (crickets and grasshoppers) and caterpillars which were significantly reduced for several weeks (moderate risk). Vegetation dwelling and flying insects were moderately affected by FE. Non-target butterfly densities increased towards the end of the trial which appeared to be related to a significant reduction in hymenopteran predators and parasitoids. TFM had a marked effect on butterflies (>60%), but was harmless to the other insects. Spiders responded less sensitively to pesticide stress than insects, but orb web spiders were significantly reduced by fenitrothion-esfenvalerate. The breakdown of organic matter was not affected by any of the insecticides. The results suggest the following relative field toxicity ranking: TFM相似文献   

3.
The effectiveness of vacuum (V) treatment alone and in combination with an oxygen absorber (V + A) for suppression of grain infestation by Sitophilus granarius L. were compared under laboratory conditions. The effectiveness of the treatment methods was evaluated at different temperatures (15, 25 °C) and exposure times (7, 14, 21, 28 days). We evaluated both the effects on adults present in grain interspaces and hidden infestations within the kernels in terms of treatment time separately. Adults of S. granarius present in grain interspaces were more susceptible to both treatments than hidden infestations developing within kernels. At 25 °C, total mortality of adults in grain interspaces was achieved after 10 days of exposure whereas total suppression of hidden infestations was achieved after 3 weeks. Higher temperature and longer exposure correlated with a greater effectiveness of the tested treatments. The addition of an oxygen absorber to the vacuum treatment (V + A) showed the general tendency of improving the effectiveness of the vacuum treatment on suppression of hidden infestations; significant differences between the V + A and V treatments were prominent primarily at the lower temperature tested. Reduction of hidden infestation was achieved after 3 weeks of exposure to V + A treatment (99.8%) and after 4 weeks of V treatment (95.8%) at 15 °C.  相似文献   

4.
We investigated the application of phosphine at low pressure for various exposure durations against major stored-product insects in a commercial dried fig processing facility in Central Greece. Trials were carried out inside a chamber, in which phosphine, in the form of aluminium phosphide pellets, was introduced with the use of a phosphine generator. The generator unit was also equipped with a vacuum pump to achieve low pressure inside the chamber. The chamber was filled with pallets with boxes containing figs. The insects tested were Tribolium confusum (all life stages), Ephestia elutella (eggs and larvae), Sitophilus oryzae (adults), Sitophilus granarius (adults), Rhyzopertha dominica (adults), Oryzaephilus surinamensis (adults) and Prostephanus truncatus (adults). Moreover, wheat grains containing immature stages of S. oryzae were also used. All insect-life stage combinations were exposed to phosphine at low pressure for 18, 48 and 72 h. In most cases, significant differences in mortality of insects treated with phosphine at low pressure compared to the control treatments were recorded. However, complete control (100%) was recorded only in the case of O. surinamensis adults and T. confusum larvae after exposure for 48 and 72 h, respectively. We conclude that the combined application of phosphine and low pressure at short exposure durations (up to 72 h) cannot provide sufficient control at least against the stored-product insect species and life stages tested in the present study.  相似文献   

5.
Maize rough dwarf virus (MRDV) has emerged as a major constraint to maize crop production in Spain. The seasonal abundance of planthopper-vectored MRDV was studied during two consecutive years in trials located within the area with the highest incidence of MRDV. Insect density was estimated once every 15 days during the maize growing season using sticky and suction traps. Laodelphax striatellus Fallén was the sole planthopper present in these maize trials and 52% of the captured hoppers contained MRDV. The population of L. striatellus showed two peaks during the season; one in June and the other in September. Adults of L. striatellus were captured from mid-May to the beginning of October and viruliferous insects were captured from 18th May to the beginning of September. Levels of the incidence of MRDV were correlated with the first detection of planthoppers (whether carrying the virus or not) in maize fields during the early development stages of the crop, but not with the planthopper abundance. The data obtained in this study support that early sowing of maize could contribute to reduce the incidence of MRDV in the northeast of Spain.  相似文献   

6.
美国转基因玉米的生产概况和发展趋势   总被引：1，自引：1，他引：1  
陈化榜 《玉米科学》2008,16(3):001-003
美国是世界上最大的玉米生产国, 种植面积、总产和单产均居世界首位。转基因玉米自1996年引入生产以来,使玉米生产上了一个新台阶。当前推广利用的转基因玉米品种基本上是抗虫和抗除草剂两种类型。抗虫是由在玉米体内表达Bacillus Thuringiensis(Bt)毒素结晶蛋白(cry蛋白)基因所致,除草剂的抗性(Herbicide tolerance, HT)是由外源的或改良的EPSPS基因在玉米体内表达来实现。转基因玉米的种植面积每年都稳步上升,转基因玉米的也由单一的Bt或HT转变为多基因多性状的叠加,将抗玉米螟和抗Rootworm结合,使玉米的地上部和地下部都得到了有效的保护,再加之抗除草剂基因的叠加,使得转基因品种在生产上更具竞争力。转基因玉米的抗虫和抗除草剂等优良性状带来了巨大的经济和环境效益, 并被越来越多的大众所接受。转基因玉米在短短10年间的应用和发展,还不能回答转基因作物对人类和环境的长期影响等问题。因此,对转基因作物的管理和利用仍不能掉以轻心,不能因对生物技术的热情而对人类和环境造成无意的不可挽回的破坏。  相似文献   

7.
A precision seeding device for true potato seed   总被引：1，自引：0，他引：1  
A prototype apparatus was developed which can select and deliver single true potato seed to a specific location. The principle features of the unit include a system of vacuum and pressure nozzles connected to a rotating head to select and hold the individual seeds then eject them for planting. An airbrush was incorporated in the design to remove multiple seed from the nozzles. A small orifice and the radially oriented airbrush were fixed as a result of preliminary tests. Results of performance studies of the unit indicated that 84% single seed selection was possible. Parameters which influenced the performance of the unit were airflow rate from the airbrush and the level of vacuum in the manifold.  相似文献   

8.
Hematophagous arthropods transmit the etiological agents of numerous diseases and as a result are frequently the targets of sampling to characterize vector and pathogen populations. Arguably, the most commonly used sampling approach involves traps baited with carbon dioxide. We report results of a laboratory study in which the performance of carbon dioxide-baited traps was evaluated using measures of baiting intensity, the amount of carbon dioxide released per unit time during trap deployment. We evaluated the effects of trap design, carbon dioxide source, and wind speed on baiting intensity and documented significant effects of these factors on the length of sampling (time to baiting intensity = 0), maximum baiting intensity, and variation in baiting intensity during experimental trials. Among the three dry ice-baited trap types evaluated, traps utilizing insulated beverage coolers as dry ice containers sampled for the longest period of time, had the lowest maximum but most consistent baiting intensity within trials and were least sensitive to effects of wind speed and dry ice form (block vs. pellet) on baiting intensity. Results of trials involving traps baited with carbon dioxide released from pressurized cylinders suggested that this trap type had performance comparable to dry ice-baited insulated cooler traps but at considerably higher cost.  相似文献   

9.
Foliar late blight, caused by Phytophthora infestans, is an important disease problem worldwide. Foliar resistance to late blight was found in a hybrid population of the cultivated diploid species Solanum phureja-S. stenotomum (phu-stn). The objective of this study was to determine if resistance to late blight could be improved by recurrent maternal half-sib selection in the phu-stn population. Four clones from each of 72 maternal half-sib families plus the check cultivar ‘Atlantic’ were evaluated for late blight resistance in replicated field trials in Pennsylvania. The most late blight resistant clone from each of the 72 families was randomly intermated to advance the population. The cycle 1, 2, and 3 populations were evaluated in 1996–1997, 2003–2004, and 2009–2010, respectively. Percent infected foliage was recorded several times towards the end of the growing season and used to compute area under the disease progress curve (AUDPC). Mean AUDPC was 652 (cycle 1), 556 (cycle 2), and 276 (cycle 3), whereas the mean AUDPC of ‘Atlantic’ ranged from 775 to 863 each cycle. Narrow-sense heritability for resistance was estimated as 0.78, 0.77, and 0.80 in cycles 1, 2, and 3, respectively. Recurrent maternal half-sib selection continues to improve the levels of resistance to late blight in this diploid population with no adverse effect on the amount of additive genetic variance. Additional improvements for late blight resistance are likely to occur if this approach is continued.  相似文献   

10.
In vitro and in-planta trials were conducted to determine the nemato-toxic potential of aqueous leaf extracts of Betel (Piper betle L.) against the root-knot nematode species, Meloidogyne incognita, at five concentrations, standard extract (S) [1:2 (w/v] and its four dilutions, 20%, 40%, 60%. 80% of S. In the in vitro trials, second-stage juveniles (J2s) and eggs of M. incognita were directly exposed to the extract while in the in-planta trials, the effect of the extract was evaluated as a root dip treatment using tomato plants. The findings indicated that the extract was lethal to J2s but also inhibited egg hatch. The seedling dip treatments reduced root infestations in terms of gall formation, egg production and J2 population densities in soil while simultaneously enhancing the growth of tomato plants. All these effects varied in a dose-dependent manner. Based on the LC50 value, the eggs were found to be less sensitive to the extract than J2s. One hundred percent of mortality of J2s was recorded at four concentration levels, 40%, 60% and 80% of S and S, while 100% egg inhibition was only recorded at S. The highest reductions in gall formation (i.e., number of galls/root system), egg production and J2 population were all recorded at S as 83%, 87% and 84% compared to the untreated water control. The maximum growth enhancement, which was 235% of the control, was detected in the root length of treated tomato plants. It appears the aqueous leaf extract of P. betle shows promise as a sustainable eco-friendly nematicide for the management of M. incognita.  相似文献   

11.
The effects of increasing the population density of the cowpea coreid, Clavigralla tomentosicollis Stål., up to a maximum of 32 pairs of insects per cage, infested on cowpea at either early flowering or mid pod-fill, were studied in potted plants and field cages. Overall, the results show that increasing insect density resulted in a corresponding increase in damage to the crop (measured as abscission of fruiting bodies and as damage to pods and seeds). Yield reduction was approximately proportional to the bug population when low, with highly significant correlation coefficients. Damage to the crop and yield reduction were more drastic when infestation was made during flowering as opposed to infestation at podding; although there was some compensation of damage to fruiting bodies during the former growth phase, this was not sustained with increasing pest density. Suggested pest densities at which control measures should be initiated are two insects (fourth instar and over) per 10 plants at flowering and four insects at podding. Further studies on damage thresholds in multiple pest scenarios are suggested.  相似文献   

12.
Russet Legend, a moderately late maturing variety especially suitable for frozen French fry processing but also acceptable for tablestock use (boiling, and baking), was jointly released by the Agricultural Experiment Stations of Oregon, Colorado, Idaho, and Washington, and the U.S. Department of Agriculture in 1998. Russet Legend was evaluated in irrigated trials in Oregon from 1988 to 1997, and in western regional trials from 1990 to 1992. Total yields were similar to those of Russet Burbank, but Russet Legend produced higher marketable yields. In three years of regional trials at up to 13 locations in seven western states, Russet Legend averaged 47.3 Mg/ha marketable yield compared with 36.5 Mg/ha for Russet Burbank and 33.6 Mg/ha for Russet Norkotah. Russet Legend has consistently achieved lighter fry color and higher specific gravity than Russet Burbank. Russet Legend is less susceptible toVerticillium wilt than Russet Burbank or Russet Norkotah. It is susceptible to PLRV and net necrosis, and expresses PVY foliar symptoms clearly. Russet Legend is less susceptible to tuber infection and decay caused byPhytophthora infestans than Ranger Russet and Russet Norkotah. Russet Legend is less susceptible to hollow heart, brown center, growth cracks, and sugar ends than Russet Burbank  相似文献   

13.
The Danish decision support system Crop Protection Online (CPO) optimises herbicide weed control. CPO recommends specific herbicide solutions to achieve a required level of control. The aim is to apply herbicides as little as possible but as much as necessary. CPOWeeds is a version of CPO adjusted to conditions in North-eastern Spain. The predicted efficacies and the yield obtained with CPOWeeds were validated in winter cereal field trials from 2010 to 2013. All CPOWeeds treatments were related to the efficacies obtained with standard herbicide treatments decided upon by local advisors. The predictions from CPOWeeds were compared to the actually achieved efficacies in the field trials for the nine weed species at different developmental stages and for 84.2% of the comparisons the obtained efficacies were equal to or higher than predicted. The average difference between predicted and observed efficacies was 2.35 percentage points. Yield was measured in three trials and the recommendations from CPOWeeds were maintaining yield. There were two situations where CPOWeeds were performing suboptimal. One is in the early weed growth stages, as the model is not yet prepared to account for water stress on root action herbicides applied at 10-11 BBCH. The second situation was in fields with a prior unidentified population of resistant Alopecurus myosuroides. For key species in winter cereals in Spain, such as Avena sterilis, Lolium rigidum and Papaver rhoeas, CPOWeeds achieved a satisfactory control level. It was concluded that the use of CPOWeeds allowed optimisation of the herbicide application with a very high robustness. The recommendations were satisfactorily for the conditions of the Northeast of Spain and have the potential to decrease the amount of applied herbicides by at least 30%. Therefore, it can be an important tool in Integrated Weed Management.  相似文献   

14.
Bollgard® and BollgardII® cotton cultivars were evaluated for their efficacy for control of bollworms and their effects on sucking insects and the abundance of natural enemies under bollworm insecticide protected and non-insecticide protected field conditions during the 2004 and 2005 cropping seasons. Bollgard cultivars are genetic transforms that produce Cry1Ac toxins from Bacillus thuringiensis (Bt) to control American bollworm, Helicoverpa armigera. Second generation BollgardII cultivars contain 2 toxins, Cry1Ac and Cry2Ab, and are more effective in controlling a broader range of caterpillar species. Bollgard cultivars were free of H. armigera damage until harvest under insecticide protected as well as non-protected conditions. Both BollgardII and Bollgard cultivars were infested with larvae of spotted bollworm, Earias vitella, and spiny bollworm, Earias insulana, at later crop growth stages. Neither BollgardII nor Bollgard cultivars were free of square (fruiting body), open boll and loculi damage. Bollworm damage did not reach economic threshold levels up to harvest. Densities of sucking insects (Amrasca biguttula biguttula, Bemisia tabaci, Aphis gossypi, and Thrips tabaci), of the foliage feeder Myllocerus undecimpustulatus and of predators (Chrysoperla spp., Orius spp., Coccinella spp., Brumus spp., Vespa spp., Lycosa spp., and Aranews spp.) were similar on Bollgard, BollgardII and conventional cultivars. The time of the first appearance of bollworms, sucking insects and predators on Bt cotton did not vary from conventional cotton varieties. Insecticidal protection based on economic threshold levels resulted in significant reductions in bollworm damage on conventional cultivars.  相似文献   

15.
Neosaxitoxin (NeoSTX) is a specific reversible blocker of voltage gated sodium channels on excitable cells. In the last decade, it has been tested in a number of interesting clinical trials, however there is still little information available on mammalian toxicity. Rats were treated for 12 weeks with doses of 1, 3 or 6 μg/kg of subcutaneous NeoSTX. At weeks 12 and 17, animals were sacrificed and blood samples collected for hematological and biochemical analysis. Organs were harvested for weight determination and histopathological assessments. The lowest acute toxicity via the intraperitoneal (ip) route was (30.35 μg/kg) and there was no significant difference between intramuscular and subcutaneous routes (11.4 and 12.41 μg/kg). The NeoSTX adiministration did not produce lethality at week 12 and after five weeks of suspension. NeoSTX 6 μg/kg ip produced reductions (p < 0.05) in body weight and food intake, and increased blood level of total and direct bilirubin, GGT and SGOT at week 12; all of these were reversed in the recovery period. NeoSTX 1 and 3 μg/kg ip did not show significant changes with the control group. Histopathological presentations were normal in all groups. This study revealed that NeoSTX is safe in vivo, giving a reliable security margin for its use like a local anesthetic.  相似文献   

16.
油菜倒伏严重影响了油菜的产量和品质,为了定位甘蓝型油菜（Brassica napus L.）与抗倒伏性状相关的QTL,用抗倒伏品系浙平1号和易倒伏品系高芥1号组合重组自交系（RIL）家系为材料,通过两年两点试验,对该RIL群体的F2:6和F2:7家系抗压力性状进行了QTL分析,并应用一年两点数据对该群体F2:6家系结角层性状进行了QTL分析。结果表明,在4个试验中共检测到11个家系抗压力QTL,可解释4.41%～52.64%的表型变异,LOD值范围是2.68～26.58。其中qRP16-1可以在3个不同的试验中（南京-2012、溧水-2012和南京-2013）重复检测到,qRP1、qRP4和qRP8-1同时在2个不同的试验中（溧水-2012和溧水-2013）重复检测到。qRP2-1、qRP2-2、qRP8-2、qRP8-3、qRP16-2、qRP3和qRP8-4等7个QTL只能在特定的试验中检测到。同一地点不同年份间家系抗压力性状QTL相对同一年份不同地点间易被重复检测到。在2个试验中共检测到2个结角层厚度QTL,位于第15连锁群的qTPL15在2个试验中重复检测到。  相似文献   

17.
In Brazil, some of the most important insect pests causing damage to soybean (Glycine max) are stink bugs. Soybean production would increase if varieties with enhanced resistance were developed. The aim of this work was to examine different traits associated with plant development, and yield-related traits, in an F2:3 soybean population in a stink bug-infested field and to evaluate genetic parameters and correlations among those traits. The parents and progeny from 229 F2 plants developed by crossing a resistant cultivar (IAC-100) with a susceptible cultivar (CD-215) were evaluated in three replications in a single environment. Seven agronomic traits and eight indicators of insect resistance were measured. Genotypes showed significant differences for all traits except lodging. The grain-filling period exhibited a positive genotypic correlation of 0.66 with hundred-seed weight, whereas a negative genotypic correlation of ?0.53 was found between pod damage index (%) and weight of healthy seeds. In general, a shorter pod-filling period, lower weight of hundred-seeds, lower indices of pod damage, and higher seed-yield per plant were phenotypic traits of genotypes resistant to these insects.  相似文献   

18.
大豆对食叶性害虫田间抗性的相对稳定性   总被引：4，自引：0，他引：4  
在已有的7年工作基础上,以叶面积损失百分率为指标,继续于2000年和2001年对51份大豆材料开展了对食叶性害虫综合虫种抗性的鉴定工作.综合分析1993-2001年历年各次田间抗性鉴定结果,发现虽然每年抗性鉴定的结果并不完全一致,但各品种的抗性水平还是保持了一定的相对稳定性.通过对各年抗性鉴定分级结果的综合分析,结合9年综合抗性分级结果,确立了10个较为稳定、并具一定代表性的抗感材料,作为大豆对食叶性害虫田间综合虫种抗性鉴定的标准品种.分别是,抗性材料:吴江青豆3、PI227687、沔阳白毛豆、通山薄皮黄豆甲、赶泰-2-2;感性材料:山东大豆、大青瓤黑豆、矮杆黄、商丘7602和皖82-178.  相似文献   

19.
Metabolic syndrome is a risk factor for cardiovascular diseases and has become increasingly common in Japan. Epidemiological studies show inverse associations between intake of whole wheat grains and metabolic syndrome, but few dietary intervention trials have investigated the effect of whole wheat grain consumption. It was investigated whether a diet in which refined wheat bread (RW diet) was substituted by whole grain wheat bread (WW diet) would reduce visceral fat obesity in Japanese subjects. A randomized double-blind placebo-controlled intervention study was conducted in 50 Japanese subjects with body mass index (BMI)?≥?23 kg/m2. Subjects were randomly assigned WW (WW group) or RW diets (RW group) for 12 weeks. Blood samples and computed tomography scans were obtained every 6th week. The WW group showed decrease (?4 cm2) in visceral fat area (VFA) (p <?0.05), whereas the RW group showed no significant changes. These time-dependent changes were significantly different between the groups. WW diet led to significant and safe reductions in VFA in subjects with BMI?≥?23 kg/m2. WW diet may contribute to preventing visceral fat obesity.  相似文献   

20.
Three types of poison (parathion, strychnine and bromadiolone) were evaluated with regard to their efficacy in controlling mouse plagues in a standing crop such as irrigated sunflower. Two techniques, mark-recapture and census baiting, were used in these evaluations. Census baiting appeared to give the most realistic appraisal of the efficacy of each poison: by this method the population reductions were estimated as 42, 63 and 90% respectively. Bait was applied into the crop aerially at a rate of 5 kg/ha total coverage. Movement data collected during the mark-recapture study are also discussed in terms of relevance to poisoning strategy.  相似文献   

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