共查询到20条相似文献，搜索用时 31 毫秒
1.
Guoping Li Hongqiang Feng Jeremy N. McNeil Bing Liu Peiyu Chen Feng Qiu 《Crop Protection》2011,30(12):1573-1578
Transgenic Bt (Bacillus thuringiensis) cotton has been effectively used to control the cotton bollworm, Helicoverpa armigera (Hübner) in China. However, in recent years, following the wide commercialization of Bt cotton in northern China there have been frequent outbreaks of the non-target pest Apolygus lucorum (Meyer-Dür). To clarify how transgenic cotton contributes to these outbreaks, a four-year field investigation of population dynamics and laboratory life table studies were carried out from 2007 to 2010 to evaluate the impact of two transgenic cotton cultivars (SGK321 expressing Cry1Ac + CpTI and GK12 expressing Cry1Ac) and their corresponding parental non-transgenic lines (Shiyuan321 and Simian3) on A. lucorum. There were no significant differences in the population densities of A. lucorum found in Bt cotton and non-Bt cotton plots, whether one compared those that had received insecticide treatments or those that had not. However, population densities of A. lucorum were significantly lower in pesticide treated plots than in controls. Furthermore, there were no significant differences in the net reproductive rates, generation times or intrinsic rates of increase of A. lucorum when reared on either Bt or non-Bt cotton cultivars. These results suggest that Bt cotton has no direct positive or negative effects on the biology of A. lucorum, so the most logical explanation for the observed outbreaks is the decrease in pesticide applications following the commercial release of Bt cotton. 相似文献
2.
Bacillus thuringiensis (Bt) transgenic cotton has been planting in large-scale for more than 10 years in China. It was observed that resistance to bollworm was reduced with the application of big-boll cultivars in China. The objective of the study was to investigate the effects of boll size on the contents of CryIA insecticidal protein in boll shell and cotton seed during the course of boll development. Two experiments were conducted at the Yangzhou University Farm, Yangzhou, China. In 2004, three cultivars including Sikang 1 (small-boll), Xiangza 3 (medium-boll) and Kemian 3 (big-boll) were compared for boll shell volume and 100-seed weight from 10 to 40 days after flowering (DAF), and insecticidal protein contents in boll shell and cotton seed from 10 to 50 DAF. As expected, the differences between cultivars were significant for all the four characteristics. Cultivars with bigger boll shell volume had higher 100-seed weight but lower insecticidal protein contents in both of the boll shell and cotton seed. The correlation between boll size and boll insecticidal protein content was negative (−0.653). The correlation between 100-seed weight and cotton seed insecticidal protein content was significantly negative (−0.645). In 2005, leaf cut (LC) and square removal (SR) treatments were applied to Sikang 1 and Sikang 3. The boll shell volume and 100-seed weight were decreased by LR, but increased by SR. LC significantly enhanced and SR significantly reduced the insecticidal protein contents of boll shell and cotton seed. The correlation between boll size and boll insecticidal protein content (−0.870) and the correlation between 100-seed weight and cotton seed insecticidal protein content were both highly significant and negative (−0.841). Therefore, the results of the study indicated that the boll insecticidal protein content was significantly affected by boll size. The implications of the observed results in breeding, cultural practices and pest management were discussed. 相似文献
3.
我国转基因棉花研究与应用进展 总被引：4，自引：0，他引：4
我国转基因棉花研完近10年，取得重大进：研制出单价Bt和双价Bt/CpTI转基因抗虫棉。已审定的品种正在生产上大面积推广，累计达160khm^2；建立了Bt棉的遗传育种、栽培、良种繁育、抗虫性鉴定、棉铃虫的抗性治理、棉田害虫综合防治以及安全性评估等一整套技术体系；棉花抗病基因工程和棉纤维品质改良的基因工程也取得了进展。 相似文献
4.
Cotton bollworm (Heliothis armigera) is a major pest of cotton and other crops. It is important to understand the mechanisms of insecticide tolerance of cotton bollworm on cotton cultivars with host plant resistance to this insect pest. The objectives of this study were to investigate the effects of cotton pigment glands and their gossypol on the growth, development and insecticide tolerance of cotton bollworm. Three pairs of cotton isogenic lines with glanded versus glandless leaves, as well as artificial diets with 5 levels of gossypol, were used to raise cotton bollworm larvae for five generations. The growth, development and insecticide tolerance of larvae were studied. The results indicated that the cotton pigment glands and higher levels of gossypol resulted in a significant decrease in larval weights and moth eclosion rates and delayed the development of larvae and pupae. Larvae that fed on glanded cotton leaves were significantly more tolerant to two insecticides, cyhalothin and monocrotophos, than those fed on glandless cotton leaves. LD50 values were only increased where they were in amount per unit body weight, and not where were calculated in amount per individual. Also the insecticide tolerance of cotton bollworm larvae increased as the gossypol content was raised from 0 to 0.225% in artificial diets. Meanwhile, the activities of two detoxifying enzymes, carboxylesterase and glutathione s-transferase, were significantly higher in the larvae fed on glanded cotton leaves than those fed on glandless cotton leaves. The activities of two enzymes also increased greatly with the increase of gossypol content from 0 to 0.225% in artificial diets. Across 5 generations of feeding and investigation, the significant inhibition effect on larval growth and larval tolerance to two pesticides were found to be only associated with the feeding by current generation, but were not related to previous diets. The activities of two detoxifying enzymes in larvae were also not enhanced significantly when they were fed continuously on glanded cotton leaves or artificial diet with high gossypol. These results indicated that pigment glands and higher levels of gossypol not only inhibited the growth of cotton bollworm larvae but also enhanced their insecticide tolerance. However, the inhibition effect and enhanced insecticide tolerance were inducible but could not be accumulated or inherited. These results will help us better understand the interaction and co-evolution of insecticide tolerance in larvae of cotton bollworm and host chemical components, and also has provided useful information on cotton bollworm management in cotton production, especially in glandless cotton. 相似文献
5.
Morphological and physiological responses and the recovery ability of Paspalum accessions to water deficit and waterlogging 
下载免费PDF全文
下载免费PDF全文 T. Beloni C. G. Pezzopane G. A. Rovadoscki A. P. Fávero M. B. Dias‐Filho P. M. Santos 《Grass and Forage Science》2017,72(4):840-850
Limited knowledge about the agronomic potential of Paspalum species from the Americas hinders their use in pastures. The response mechanisms to water deficit and waterlogging were studied in five accessions of Paspalum sp. (P. regnellii cv. BRS Guará and BGP 397, P. conspersum BGP 402 and P. malacophyllum BGP 289 and BGP 293) and Urochloa brizantha cv. Marandu. Morphological and physiological traits at the end of the stress and after the recovery period were measured. All Paspalum accessions, especially BGP 289, BGP 402 and BGP 397, and also cv. Marandu, showed survival mechanisms to water deficit. BRS Guará showed adaptive features to waterlogging, although had with a low survival rate to water deficit. Under waterlogging, BGP 289 and cv. Marandu showed reduced growth, and after the recovery period, they presented low plant survival and root recovery. Although growth of BGP 293 was reduced during waterlogging, it presented high tiller survival rate. BGP 293, BGP 402 and BGP 397 showed adaptive potential strategies for waterlogging and water deficit. There is genetic variability among the evaluated accessions for water deficit and waterlogging stresses, suggesting that they may be used per se or as progenitors in crosses with other genotypes in breeding programmes. 相似文献
6.
Quang Le Dang Gee Young Lee Yong Ho Choi Gyung Ja Choi Kyoung Soo Jang Myung Soo Park Ho Seob Soh Young Hee Han Chi Hwan Lim Jin-Cheol Kim 《Crop Protection》2010
Several organic solvent extracts of Chenopodium ficifolium were tested for their insecticidal activity against melon and cotton aphid, Aphis gossypii, on cucumber plants. Both methanol and ethanol extracts, at 5000 μg ml−1, were highly active giving over 80% control. The other crude extracts displayed moderate or weak insecticidal activity giving control in the range of 16–69%. Two phospholipids were isolated as insecticidal active substances from C. ficifolium. Their chemical structures were identified as 1-palmitoyl-2-(3-trans)-hexadecenoyl-sn-glycero-3-phosphoglycerol and 1-palmitoyl-2-linoleoyl-3-glycerophosphocholine by GC–MS, EDS, mass and NMR spectral analyses. Both compounds displayed a dose-dependent mortality of A. gossypii. Furthermore, the liquid formulation that was obtained by partitioning with n-hexane from the methanol extract of C. ficifolium controlled melon and cotton aphid on cucumber plants effectively. These results indicate that extracts of C. ficifolium have potential for development as botanical insecticides for controlling A. gossypii infesting cucumber plants. 相似文献
7.
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
8.
9.
Pheromone-baited traps are an important sampling tool in integrated pest management programmes. Studies were conducted to determine the relationship between catches of male insects in these traps, and crop infestation. Numbers of male moths of the pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), caught daily in cotton fields at the University of Arizona Cotton Research Center, Phoenix, Arizona, in gossyplure-baited traps were variable. However, average catches of male moths for 3–7 days between boll-sampling periods were strongly correlated with oviposition on cotton bolls, percentages of infested bolls and numbers of larvae per boll. Average weekly numbers of moths emerging from infested cotton were also strongly correlated with the number of males caught: the number of females emerging was strongly correlated with oviposition on cotton bolls. Insecticide applications of carbaryl and fenvalerate reduced catches of male moths of pink bollworm in gossyplure-baited traps compared with catches in traps in untreated fields (average 56%). However, 13–48 male moths/trap per night were caught in the treated fields after applications. Thus, scheduling treatments on the basis of male moth trap catches, except for the initial treatment, was not feasible. Small field sizes, moth immigration and/or continuing emergence from the infested cotton in the fields may have obscured the impact of the insecticide treatments on adult moth populations. 相似文献
10.
《Plant Production Science》2013,16(4):451-459
AbstractSoil compaction often creates combined physical stresses of drought, anaerobiosis, and mechanical impedance in field soil. This paper aims to analyze the effect of combined and independent soil physical stresses on crop root growth to find out the species-specific response to the physical stresses, which has not been reported before. Drying stress without the increase of mechanical impedance was evaluated in a very loose pot soil environment. This drying stress did not modify the root elongation rates of rice and pea by the 48 h exposure to the stress environment. For maize and cotton, however, mild drying stress (?80 kPa Ψw) enhanced root elongation by 17-18%, but severe drying stress (?900 kPa Ψw) reduced it by 17-21% as compared with the control environment (?10 kPa Ψw). The combined stress of drying and mechanical impedance nearly stopped the root elongation in all the species, while that of anaerobiosis and mechanical impedance did not stop the elongation of rice and cotton; cotton elongated about 32% of control environment. In maize, root diameter was reduced by the severe drying stress due to the reduction in the number of cortical cell layer and diameters of both central cylinder and xylem vessel. In contrast, cotton showed a significant increment of cortex diameter, although overall diameter was not statistically increased by the severe drying stress. The ability of cotton to continue elongation under anaerobiosis and mechanical stress implied the higher penetration ability to the hard pan layer under the anaerobic condition just after the heavy rainfall. 相似文献
11.
Spodoptera cosmioides (Walker), Spodoptera eridania (Stoll) and Spodoptera frugiperda (J. E. Smith) have caused significant damage on soybean Glycine max (L.) Merrill in Brazil. Genetically-modified MON 87701 × MON 89788 soybean that expresses the Cry1Ac protein is potentially an alternative tool for the management of these species. Purified protein bioassays were done to evaluate the susceptibility of S. cosmioides, S. eridania and S. frugiperda to Cry1Ac protein. The level of efficacy of the Bt soybean plants in controlling these species was measured through laboratory and greenhouse trials under high artificial insect infestations. The biology of these insects was evaluated over their development cycles to understand their life history when fed on Bt soybean. Purified Cry1Ac protein at the maximum concentration tested (100 μg Cry1Ac mL−1 diet) resulted in low mortality of S. cosmioides and S. eridania (<13%) and intermediate mortality of S. frugiperda (50%). No significant effects of the Bt soybean plants were observed in the life table parameters of S. cosmioides and S. eridania. However, S. frugiperda fed on Bt soybean plants had a prolonged larval stage (by 5 days), reduced larvae viability, increased mean generation time (by 8 days) and reduced intrinsic rate of increase. In general, the Bt soybean plants showed poor control of Spodoptera species when evaluated by leaf-disc bioassay and greenhouse trials. Consequently, other control tactics must be used in combination with MON 87701 × MON 89788 soybean in the field for the efficient management of S. cosmioides, S. eridania and S. frugiperda. 相似文献
12.
《Field Crops Research》1998,56(3):287-299
Transgenic cotton varieties expressing Cry IA(c) insecticidal proteins from Bacillus thuringiensis (`Bt cotton') remain vulnerable to non-lepidopteran insects. In addition, they are susceptible to lepidopteran pests when the efficacy of Bt toxins falls because of ontogenetic and/or environmental factors. Hence the importance of knowing to what extent Bt cotton is able to tolerate damage. The degree of tolerance of Bt cotton to actual and simulated insect damage was assessed in three field experiments. Exp. 1 compared the effects of Helicoverpa spp. (Lepidoptera: Noctuidae) on the growth, development and yield of Bt cotton with those of its near isogenic non-Bt counterpart in two genetic backgrounds (Siokra V15, Sicala V2) under two regimes of chemical control of insects (S1: nine insecticide applications during the growing cycle, S2: six insecticide applications). Exp. 2 compared insecticide-protected Bt crops with crops manually damaged to simulate (a) early-season loss of vegetative buds, (b) loss of flowerbuds, and (c) loss of both vegetative and reproductive buds. Also using manual damage, Exp. 3 evaluated the effect of timing of flowerbud loss on the yield and maturity time of insecticide-protected Bt crops. In Exp. 1, well-protected Bt crops (S1) yielded 24% more than their less-protected counterparts (S2). The less protected crops had, however, substantially more immature fruit at the end of the season highlighting a considerable potential for recovery. Poor soil conditions, interacting with season length accounted for the difference between potential and actual compensation in crops that were exposed to almost continuous damage by Helicoverpa spp. Under more favourable growing conditions, maturity was delayed but yield of damaged Bt crops was unaffected by discrete episodes of simulated herbivory (Exps. 2 and 3). The introduction of B. thuringiensis genes into cotton does not seem to have reduced the considerable capacity of the crop to tolerate insect damage, and this attribute should be considered in the development of pest management strategies for Bt crops. 相似文献
13.
通过室内生物测定,研究球孢白僵菌和苏云金芽胞杆菌联合防治玉米螟的效果。研究表明,确定白僵菌与苏云金芽胞杆菌浓度分别为1.0×106孢子/mL、1.0×109孢子/mL条件下,杀虫效果达到最佳,LT90为6.64(±0.07)d,较1.0×109的Bb LT90缩短26.06%。通过助剂悬浮率、乳化效果以及助剂对微生物活性影响等确定1个白僵菌与苏云金芽孢杆菌水悬浮剂剂型配方。田间防治玉米螟结果表明,两种生防菌均在防治过程中起作用,田间玉米受害株数、活虫数均明显低于未施药对照,防治效果优于单一使用白僵菌或苏云金芽胞杆菌。 相似文献
14.
Xiaojun Yang Xingxia Ma Lijun Yang Dazhao Yu Yixin Qian Hanwen Ni 《Crop Protection》2009,28(12):1031-1035
Rheum officinale liquid formulation, the ethanol extract from roots of R. officinale Baill., formulated as physcion 5 g l−1 aqueous solution (AS), has been commercialized in China for controlling cucumber powdery mildew (Podosphaera xanthii (Castagne) U. Braun & Shishkoff). The efficacy of the product was evaluated in pot tests under controlled conditions and in open and protected fields in China over 2 years. In most trials, the efficacy reached above 80% at the rates of 10–50 mg a.i l−1 water after three applications and at the rates of 20–50 mg a.i l−1 water after two applications. The cucumber fruit yield in the product treatment was as many or more as triadimefon treatment, and over 53.1% compared to the untreated control. These results showed that Chinese rhubarb extract could be an effective alternative plant protecting agent in the integrated and biological management of cucumber powdery mildew. 相似文献
15.
Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a serious pest of cotton and many other crops in northern China. To evaluate the contribution of alternative hosts as an effective refuge for transgenic cotton expressing the Bacillus thuringiensis (Bt) Cry1Ac toxin, the susceptibility to this toxin was measured in progeny derived from field-collected H. armigera larvae and pupae from different hosts in the Xiajin’s region of the Shandong Province in northern China. During 2008-2010, progeny from a total of 258,56,184 and 160 single-pair crosses derived from wheat (first-generation), Bt cotton (second-generation), Bt cotton (third-generation), and corn (third-generation) were screened on Cry1Ac diets, respectively. Based on relative average development rates (RADR) of H. armigera larvae in these F1 tests, the second and third-generation moths emerging from Bt cotton fields were more tolerant to the Bt toxin than the first and third-generation moths emerging from wheat and corn each year. These results suggest that there is significant variation in susceptibility to Bt toxins among H. armigera populations derived from different host crops. Alternate crops, such as corn, that maintain Bt susceptible populations of H. armigera could be used as refugia to minimize the evolution of resistance to Bt cotton. 相似文献
16.
Field experiments were conducted in 2012 and 2013 during drought conditions in South Texas and the Texas High Plains to test whether cotton water-deficit stress, age, and cultivars are moderating and interacting factors that affect cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae), abundance and yield loss. Irrigation and sequential plantings of several cultivars were used to simulate a range of water stress, plant ages, and cultivar variability. Cotton grown under these experimental conditions were exposed to cotton fleahopper using natural and artificial infestation. Cotton cultivars had a strong influence on cotton fleahopper abundance, with higher densities on Stoneville cultivar 5458 B2RF, which is relatively pubescent, than on the Phytogen cultivar 367 WRF, which is relatively glabrous, in South Texas (p < 0.04). But the strong cultivar effects on cotton fleahopper abundance did not correspond to yield reduction. No water stress effects on cotton fleahopper densities were observed in 2012 (p > 0.05), whereas cotton fleahopper densities increased on older cotton grown under no water stress in 2013 in South Texas (p < 0.05). In contrast, yield response was primarily sensitive to soil moisture conditions (up to 50% yield reduction when grown in dryland mimic conditions below 75% crop ET replacement, p < 0.0009). Water and cotton fleahopper stress synergies were detected but variable, with greatest lint yield loss attributable to cotton fleahopper seen in cotton grown in high water stress conditions in the High Plains (p < 0.05). Yield trends were consistent across cultivars (no interaction with cultivar), even though cotton fleahopper populations varied significantly across cultivars and exceeded regional economic thresholds beginning the second week of squaring (p < 0.05). 相似文献
17.
Pheromone trap catches as a means of predicting damage by pink bollworm larvae in cotton 总被引：3，自引：0，他引：3
The male moth catches in gossyplure-baited traps were used to predict larval infestation of pink bollworm, Pectinophora gossypiella (Saunders), in cotton fields during 1988 and 1989. The mean moth catches per trap per night were positively correlated with percentage larval infestation. The moth counts in traps and larval infestation in green bolls increased with advance in reproductive stage of the cotton plants. A mean trap catch of 9–12 pink bollworm moths per night was associated with economically damaging infestation. It is, therefore, inferred that insecticidal sprays may be scheduled when 9–12 moths are captured per trap per night. 相似文献
18.
转Bt基因抗虫棉毒蛋白检测方法及其表达规律研究进展 总被引：1，自引：0，他引：1
研究转Bt基因抗虫棉毒蛋白的表达规律及其对标靶害虫毒杀性,对评价Bt基因成功转化、转Bt基因抗虫棉选育和推广、目标害虫抗性预测以及生物安全评价管理都具有重要意义。概述了国内外转Bt基因棉毒蛋白检测方法及其表达变化规律,并提出引起Bt毒蛋白表达变化的原因及改进对策。 相似文献
19.
转Bt毒蛋白基因玉米及其抗虫性研究进展 总被引：4，自引：3，他引：4
本文从转Bt毒蛋白基因玉米的培育及商品化，Bt毒蛋白基因在转基因玉米中的遗传分离与整合、对玉米螟及其它害虫的杀虫效果、对天敌种群数量和玉米病害发生程度的影响、玉米螟对转Bt毒蛋白基因玉米产生抗性及解决措施、应用转Bt毒蛋白基因玉米潜在的生态风险性等方面对国内外最新研究进展进行了综述。 相似文献
20.
Large-scale adoption of transgenic crops expressing genes from Bacillus thuringiensis (Bt) imposes high selection pressure for evolution of field-relevant resistance that can reduce pest control efficacy, such as reported for Cry1F maize (Zea mays L.) in populations of fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), of Puerto Rico, Brazil, and the United States. As part of our effort to improve fall armyworm resistance management to Bt crops, here we determined the genetic basis of Cry1F resistance in two S. frugiperda strains originated from field collections in different regions of Brazil and further selected in the laboratory for high levels of resistance to Cry1F maize. Continuous exposure to the TC1507 event for 11 generations resulted in more than 183-fold resistance to Cry1F in the two strains studied, and such a high resistance level enabled the insects to complete larval development on the Bt maize plants. Genetic analyses using concentration-response bioassays with progenies from reciprocal crosses between resistant and susceptible insects indicated that the inheritance of the resistance is autosomal, recessive and without maternal effects. Backcross of the F1 progeny with the parental resistant strains revealed that the resistance in the two selected strains is conferred by a single locus or set of tightly linked loci. These results support some of the assumptions of the strategy in use for fall armyworm resistance management to Bt Cry1F maize, but survival rates of heterozygotes on the Bt plants were higher than 5%, showing that the Cry1F maize does not produce a high dose of the insecticidal protein for S. frugiperda. Additionally, we detected a delay in larval development time that may favor assortative mating of individuals carrying resistance alleles. These findings are consistent with the rapid evolution of Cry1F resistance in certain field populations of fall armyworm. Implications for resistance management of S. frugiperda to Bt maize are discussed. 相似文献