Field Conditions In China Research Articles

Effects of seaweed fertilizer application on crops' yield and quality in field conditions in China-A meta-analysis.

Seaweed fertilizer, formulated primarily with seaweed extract as its main ingredient, has been extensively studied and found to significantly improve nutrient use efficiency, increase crop yield and quality, and enhance soil properties under field conditions. This growing body of evidence shows that seaweed fertilizer is a suitable option for sustainable agriculture in China. However, a comprehensive and quantitative analysis of the overall effects of seaweed fertilizer application in China is lacking. To address this gap, we conducted a meta-analysis of relevant studies on the effects of seaweed fertilizers under field conditions in China with MetaWin and SPSS software. Our analysis examined the effects of seaweed fertilizers on crop yield, quality, and growth under different preparation methods, application techniques, and regions. Our results showed that the application of seaweed fertilizer led to a significant average increase in crop yield of 15.17% compared with the control treatments. Root & tuber crops exhibited the most pronounced response, with a yield boost of 21.19%. Moreover, seaweed fertilizer application significantly improved crop quality, with elevations in the sugar-acid ratio (38.32%) vitamin C (18.07%), starch (19.65%), and protein (11.45%). In addition, plant growth parameters such as height, stem thickness, root weight, and leaf area showed significant enhancement with seaweed fertilizer use. The yield-increasing effect of seaweed fertilizers varied depending on their preparation and use method, climate, and soil of application location. Our study provides fundamental reference data for the efficient and scientific application of seaweed fertilizers in agricultural practices.

Development of Food-Luring Baited Traps for Solenopsis invicta (Hymenoptera: Formicidae) Monitoring in the Field in Southern China

Solenopsis invicta Buren (Hymenoptera: Formicidae), a red imported fire ant that originated from South America, is a worldwide invasive pest. This study investigated the efficacy of the newly designed baited trap to detect red imported fire ants, Solenopsis invicta Buren, under field conditions in China. Among the five food lures tested for red imported fire ants, the ants preferred ham sausage and fish powder, followed by mixed powder (50% fish powder + 50% black soldier fly powder) and black soldier fly powder. These lures were compared to sugar water (control) to determine their efficacy in trapping red imported fire ants. Field data revealed that the ham sausage powder trap was more efficient than the fish powder trap based on its ability to trap more red imported fire ants under field conditions and ease of use. Thus, it was concluded that the baited traps are efficient for longterm red imported fire ants monitoring.

Residue analysis and dietary risk assessment of thiamethoxam, flonicamid and their metabolites in cucumber under field conditions in China.

Thiamethoxam and flonicamid are two representative insecticides of neonicotinoids which are used to treat cucumber aphids, causing food safety and human health problems. A 60% thiamethoxam-flonicamid commercial mixture water dispersible granule (WDG) is being prepared for registering in China, so it is essential to investigate the residue levels of these neonicotinoids and their metabolites in cucumber and evaluate the dietary risks of these insecticides. We developed a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method combined with high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) for the simultaneous determination of thiamethoxam and its metabolite clothianidin, flonicamid and its metabolites 4-trifluoromethylnicotinic acid (TFNA), 4-trifluoromethilnicotinamide (TFNA-AM), 4-(trifluoromethyl) nicotinol glycine (TFNG) in cucumber. Method validation indicated good selectivity, linearity (r ≥ 0.9996), accuracy (recoveries of 80-101%), precision (relative standard deviations (RSD) ≤ 9.1%), sensitivity (limits of detection (LOD), 0.28-1.44 × 10-3mg/L; limits of quantification (LOQ), 0.01mg/kg) and minor matrix effect (ME) ( ≤|± 5%|). In the terminal residue trials under good agricultural practice (GAP) conditions, the residue levels of six analytes in cucumber samples were ˂0.01-0.215mg/kg after application trice with an interval of 7days based on pre-harvest interval (PHI) of 3days under the high recommended dosage of 54g active ingredient/ha (g a.i./ha). Relevant toxicological, residual chemistry parameters and dietary consumption of the residents were applied to assess the potential risk of dietary exposure. The chronic and acute dietary exposure assessment risk quotient (RQ) values were less than 1. The above results indicated that the potential dietary intake risk of this formulation was negligible to consumers.

Application of Non-Aflatoxigenic Aspergillus flavus for the Biological Control of Aflatoxin Contamination in China.

Biological control through the application of competitive non-aflatoxigenic Aspergillus flavus (A. flavus) to the soil during peanut growth is a practical method for controlling aflatoxin contamination. However, appropriate materials need to be found to reduce the cost of biocontrol products. In this study, a two-year experiment was conducted under field conditions in China, using a native non-aflatoxigenic strain to explore its effect. After three months of storage under high humidity, aflatoxin levels remained low in peanuts from fields treated with the biocontrol agent. Three types of substrates were tested with the biocontrol agent: rice grains, peanut meal (peanut meal fertilizer) and peanut coating. Compared to untreated fields, these formulations resulted in reductions of 78.23%, 67.54% and 38.48%, respectively. Furthermore, the ratios of non-aflatoxigenic A. flavus recovered in the soils at harvest in the treated fields were between 41.11% and 96.67% higher than that in untreated fields (25.00%), indicating that the rice inoculum was the most effective, followed by the peanut meal fertilizer and peanut coating. In 2019, the mean aflatoxin content of freshly harvested peanuts in untreated fields was 19.35 µg/kg higher than that in the fields treated with 7.5 kg/ha rice inoculum, which was 1.37 µg/kg. Moreover, no aflatoxin was detected in the two other plots treated with 10 and 15 kg/ha rice inoculum. This study showed that the native Chinese non-aflatoxigenic strain of A. flavus (18PAsp-zy1) had the potential to reduce aflatoxin contamination in peanuts. In addition, peanut meal can be used as an alternative substrate to replace traditional grains, reducing the cost of biocontrol products.

Grasses are able to harbor the oversummering of urediospores and the overwintering of teliospores of Puccinia striiformis f. sp. tritici in China

Puccinia striiformis f. sp. tritici (Pst), the cause of wheat stripe rust, is a biotrophic and heteroecious rust fungus with five spore types. Cool and humid climatic conditions are conducive for the development of wheat stripe rust, and in turn, temperatures above 22 °C limit or even cease the disease. The survival of Pst during summer after wheat harvest is responsible for the infection on autumn-sown wheat to maintain disease cycle all the year round. Teliospores formed at late stage of wheat growth are essential for initiating sexual reproduction in spring. Although Chinese native grasses have been experimentally testified as susceptible hosts for Pst and teliospores produced on wheat have been shown to be potential inoculum sources causing infection on alternate hosts (mainly Berberis) in spring, the roles of grass hosts in harboring the survival of urediospores and teliospores of Pst and promoting the emergence of diverse races under field conditions in China have not been known. Herein, Gansu, as a hotspot and an important oversummering region for Pst, was exemplified to demonstrate these roles of grass hosts. As a result, 63 Pst isolates, derived from 2184 uredial samples collected from grass hosts during harvesting period (from mid-June to mid-to-late July) and seeding period (mid to late September) in 2012 and 2013, were identified as 52 diverse phenotypes (82.5%) on the Chinese differential hosts. Subsequently, after inoculation of barberry, 52 Pst isolates with high infection type, 20 known races and 32 new races, were recovered from 1,712 single aecium, which are derived from 35 telial samples of grass hosts. Our experiments showed that Pst urediospores can oversummer on grass species in Gansu or other oversummering regions with similar ecological and climatic conditions. Pst teliospores, which are produced on these grass hosts, are important inoculum source for barberry infection in spring. Therefore, treatment of grasses hosts should be taken into consideration in management of wheat stripe rust.

Assessment of ballast layer under multiple field conditions in China

Ballast layer condition should be more regularly and accurately inspected to ensure safe train operation; however, traditional inspection methods cannot sufficiently fulfil this task. This paper presents a method of ground penetrating radar (GPR) application to reflect ballast layer fouling levels under diverse field conditions (annual gross passing load, cleaning and renewal year, fouling composition and transportation type). The results show that the GPR-based inspection method can assess the ballast layer fouling level with a 1–7% difference from the traditional sieving results. Fouling composition (especially metal materials) has a great effect on the GPR signals, thus affecting the inspection accuracy of ballast layer fouling level. Developing diverse GPR-based fouling indicators (by distinguishing different GPR signal features) can improve the GPR inspection applicability to the diverse field conditions.

Evidence of Occurrence of Barley Crown Rust Caused by Puccinia coronata var. hordei and Sexual Reproduction of the Pathogen Under Field Conditions in China.

Crown rust of barley, caused by Puccinia coronata var. hordei, was first reported by Jin and Steffenson in 1992, and the fungus has been reported only in the United States and Hungary. In China, stripe, stem, and leaf rusts have been reported on barley, but not for crown rust. Recently, a sample (HZJ0004) of rust collected from barley in Qilian county in Qinghai, China, appeared different from the three rusts based on color, size, arrangements of uredinia and/or telia. Teliospores had crown-shaped appendages on the top. Based on the disease symptoms and morphology of urediniospores and teliospores, the fungus was identified as P. coronata var. hordei. Using the internal transcribed spacer sequences, the isolates HZJ0004 from barley and POR3 from buckthorn (Rhamnus sp.) were clustered in one clade with P. coronata var. hordei isolates from barley and Elymus repens but in a different clade from the isolate POC8 from wild oat and the varieties of P. coronata from oats and grasses. At the seedling stage, most of the tested cultivars of barley and rye were susceptible to P. coronata var. hordei isolates HZJ0004 and POR3, but the cultivars of oats, triticale, wheat, and most grasses of genera Aegilops, Brachypodium, Bromus, Calamagrostis, Deschampsia, Elymus, Festuca, and Phleum were resistant, indicating their host specialization on barley. To our knowledge, this is the first report of crown rust on barley in China.

Assessment of Ballast Layer Under Multiple Field Conditions in China

Assessment of Ballast Layer Under Multiple Field Conditions in China

Greenhouse and field evaluation of the novel herbicide QYC101 for weed control in maize (Zea mays L.) in China

A novel 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide, 4-(2-chloro-4-(methylsulfonyl)-3-((2,2,2- trifluoroethoxy) methyl) benzoyl)-1-ethyl-1H-pyrazol-5-yl 1,3-dimethyl-1H- pyrazole-4-carboxylate (QYC101), was evaluated under greenhouse and field conditions in China to determine its efficacy against weeds and safety towards maize via post-emergence (POST) applications. In the greenhouse experiment, QYC101 application at 15 g a.i. ha−1 was highly effective (>80% dry weight reduction) at controlling some major weed species present in maize production systems in China such as Solanum nigrum L., Amaranthus retroflexus L., Digitaria ischaemum (Schreb.) Schreb. ex Muhl., Setaria glauca (L.) Beauv., Setaria viridis (L.) P. Beauv. and Eleusine indica (L.) Gaertn. The tolerance results revealed that 22 of the tested maize hybrids displayed different levels of tolerance to QYC101 application at 90 and 180 g a.i. ha−1. The results obtained from the field experiments in 2016 and 2017 showed that QYC101 applications at 45, 67.5, 90 and 135 g a.i. ha−1 provided an 88.7–97.4% weed biomass reduction and a 10.1–22.2% yield increase in maize fields. These results indicate that QYC101 has great potential for weed management in maize production systems in China.

Novel haplotypes and networks of AVR-Pik alleles in Magnaporthe oryzae

BackgroundRice blast disease is one of the most destructive fungal disease of rice worldwide. The avirulence (AVR) genes of Magnaporthe oryzae are recognized by the cognate resistance (R) genes of rice and trigger race-specific resistance. The variation in AVR is one of the major drivers of new races. Detecting the variation in the AVR gene in isolates from a population of Magnaporthe oryzae collected from rice production fields will aid in evaluating the effectiveness of R genes in rice production areas. The Pik gene contains 5 R alleles (Pik, Pikh, Pikp, Pikm and Piks) corresponding to the AVR alleles (AVR-Pik/kh/kp/km/ks) of M. oryzae. The Pik gene specifically recognizes and prevents infections by isolates of M. oryzae that contain AVR-Pik. The molecular variation in AVR-Pik alleles of M. oryzae and Pik alleles of rice remains unclear.ResultsWe studied the possible evolutionary pathways of AVR-Pik alleles by analyzing their DNA sequence variation and assaying their avirulence to the cognate Pik alleles of resistance genes under field conditions in China. The results of PCR products from genomic DNA showed that 278 of the 366 isolates of M. oryzae collected from Yunnan Province, China, carried AVR-Pik alleles. Among the isolates from six regions of Yunnan, 66.7–90.3% carried AVR-Pik alleles. Moreover, 10 AVR-Pik haplotypes encoding five novel AVR-Pik variants were identified among 201 isolates. The AVR-Pik alleles evolved to virulent from avirulent forms via stepwise base substitution. These findings demonstrate that AVR-Pik alleles are under positive selection and that mutations are responsible for defeating race-specific resistant Pik alleles in nature.ConclusionsWe demonstrated the polymorphism and distribution of AVR-Pik alleles in Yunnan Province, China. By pathogenicity assays used to detect the function of the different haplotypes of AVR-Pik, for the first time, we showed the avoidance and stepwise evolution of AVR-Pik alleles in rice production areas of Yunnan. The functional AVR-Pik possesses diversified sequence structures and is under positive selection in nature.

Evaluation of fluopyram for southern root-knot nematode management in tomato production in China

The southern root-knot nematode (Meloidogyne incognita) is one of major challenges tomato growers face in vegetable production; and phase out of methyl bromide and the restricted use of soil fumigants have been accelerating application of non-fumigant nematicides for control of this economically important plant-parasitic nematode. Fluopyram, a succinate dehydrogenase inhibitor fungicide, has been widely used to control fungal diseases in vegetable crops. However, in China, little information is currently available about the efficacy of fluopyram against M. incognita and its effect on tomato yield. In this study, the nematicidal effect of fluopyram on M. incognita was investigated under laboratory and field conditions in China. In the laboratory, fluopyram was highly toxic to the second-stage juveniles (J2) and the eggs of M. incognita with the median lethal concentration (LC50) value of 2.78 and 1.70 mg L−1, respectively. In the field trials, fluopyram was effective in reducing population levels of M. incognita, meanwhile enhancing plant growth, particularly at 480 and 640 g ha−1 in two consecutive years, which was significantly greater than that of abamectin (a standard treatment) at 480 g ha−1. Moreover, there was a yield increase of 21.4%-58.5% from the treatments with fluopyram at three doses compared with the untreated control. The results from this study indicated that fluopyram was effective against M. incognita and could be used for control of root-knot nematodes in tomato production, while enhancing tomato growth and yield.

Differential effects of ozone on photosynthesis of winter wheat among cultivars depend on antioxidative enzymes rather than stomatal conductance

Five modern cultivars of winter wheat (Triticum aestivum L.): Yangmai16 (Y16), Yangmai 15 (Y15), Yangfumai 2 (Y2), Yannong 19 (Y19) and Jiaxing 002 (J2) were investigated to determine the impacts of elevated ozone concentration (E-O3) on photosynthesis-related parameters and the antioxidant system under fully open-air field conditions in China. The plants were exposed to E-O3 at 1.5 times the ambient ozone concentration (A-O3) from the initiation of tillering to final harvest. Pigments, gas exchange rates, chlorophyll a fluorescence, antioxidants contents, antioxidative enzyme activity and lipid oxidation were measured in three replicated plots throughout flag leaf development. Results showed that significant O3 effects on most variables were only found during the mid-grain filling stage. Across five cultivars, E-O3 significantly accelerated leaf senescence, as indicated by increased lipid oxidation as well as faster declines in pigment amounts and photosynthetic rates. The lower photosynthetic rates were mainly due to non-stomatal factors, e.g. lower maximum carboxylation capacity and electron transport rates. There were strong interactions between O3 and cultivar in photosynthetic pigments, light-saturated photosynthesis rate and chlorophyll a fluorescence with O3-sensitive (Y19, Y2 and Y15) and O3-tolerant (J2, Y16) cultivars being clearly differentiated in their responses to E-O3. E-O3 significantly influenced the antioxidative enzymes but not antioxidant contents. Significant interactions between O3 and cultivar were found in antioxidative enzymes, such as SOD and CAT, but not in stomatal conductance (gs). Therefore, it can be concluded that antioxidative enzymes rather than gs or antioxidants are responsible for the differential responses to E-O3 among cultivars. These findings provide important information for the development of accurate modeling O3 effects on crops, especially with respect to the developmental stage when O3 damage to photosynthesis becomes manifest.

Effects of elevated ozone concentration on CH4 and N2O emission from paddy soil under fully open-air field conditions.

We investigated the effects of elevated ozone concentration (E-O3) on CH4 and N2O emission from paddies with two rice cultivars: an inbred Indica cultivar Yangdao 6 (YD6) and a hybrid one II-you 084 (IIY084), under fully open-air field conditions in China. A mean 26.7% enhancement of ozone concentration above the ambient level (A-O3) significantly reduced CH4 emission at tillering and flowering stages leading to a reduction of seasonal integral CH4 emission by 29.6% on average across the two cultivars. The reduced CH4 emission is associated with O3-induced reduction in the whole-plant biomass (-13.2%), root biomass (-34.7%), and maximum tiller number (-10.3%), all of which curbed the carbon supply for belowground CH4 production and its release from submerged soil to atmosphere. Although no significant difference was detected between the cultivars in the CH4 emission response to E-O3, a larger decrease in CH4 emission with IIY084 (-33.2%) than that with YD6 (-7.0%) was observed at tillering stage, which may be due to the larger reduction in tiller number in IIY084 by E-O3. Additionally, E-O3 reduced seasonal mean NOx flux by 5.7% and 11.8% with IIY084 and YD6, respectively, but the effects were not significant statistically. We found that the relative response of CH4 emission to E-O3 was not significantly different from those reported in open-top chamber experiments. This study has thus confirmed that increasing ozone concentration would mitigate the global warming potential of CH4 and suggested consideration of the feedback mechanism between ozone and its precursor emission into the projection of future ozone effects on terrestrial ecosystem.

Effects of elevated ozone concentration on yield of four Chinese cultivars of winter wheat under fully open-air field conditions

Four modern cultivars of winter wheat (Triticum aestivum L.) were grown under elevated ozone concentration (E-O3) in fully open-air field conditions in China for three consecutive growth seasons from 2007 to 2009. Results indicated that a mean 25% enhancement above the ambient ozone concentration (A-O3, 45.7 p.p.b.) significantly reduced the grain yield by 20% with significant variation in the range from 10% to 35% among the combinations of cultivar and season. The varietal difference in the yield response to E-O3 became nonsignificant when the anova was done by omitting one cultivar which showed unstable response to E-O3 among the seasons. The reduction of individual grain mass accounted mostly for the yield loss by E-O3, and showed significant difference between the cultivars. The response of relative yield to E-O3 was not significantly different from those reported in China, Europe and India on the basis of experiments in open-top chambers. Our results thus confirmed the rising threat of surface O3 on wheat production worldwide in the near future. Various countermeasures are urgently needed against the crop losses due to O3 such as mitigation of the increase in surface O3 with stricter pollution control, and enhancement of the wheat tolerance against O3 by breeding and management.

Differential responses in two varieties of winter wheat to elevated ozone concentration under fully open-air field conditions

Two modern cultivars [Yangmai16 (Y16) and Yangfumai 2 (Y2)] of winter wheat (Triticum aestivum L.) with almost identical phenology were investigated to determine the impacts of elevated ozone concentration (E-O3) on physiological characters related to photosynthesis under fully open-air field conditions in China. The plants were exposed from the initiation of tillering to final harvest, with E-O3 of 127% of the ambient ozone concentration (A-O3). Measurements of pigments, gas exchange rates, chlorophyll a fluorescence and lipid oxidation were made in three replicated plots throughout flag leaf development. In cultivar Y2, E-O3 significantly accelerated leaf senescence, as indicated by increased lipid oxidation as well as faster declines in pigment amounts and photosynthetic rates. The lower photosynthetic rates were mainly due to nonstomatal factors, e.g. lower maximum carboxylation capacity, electron transport rates and light energy distribution. In cultivar Y16, by contrast, the effects of E-O3 were observed only at the very last stage of flag leaf ageing. Since the two cultivars had almost identical phenology and very similar leaf stomatal conductance before senescence, the greater impacts of E-O3 on cultivars Y2 than Y16 cannot be explained by differential ozone uptake. Our findings will be useful for scientists to select O3-tolerant wheat cultivars against the rising surface [O3] in East and South Asia.

Analysis of cyprodinil in leek and pepper and its decline under field conditions

A HPLC-UV method for determination of cyprodinil in leek, pepper, and soil was developed and the decline of cyprodinil under field conditions in China was investigated. The samples were extracted with acetonitrile. For leek and pepper samples, further clean-up with a florisil SPE column was necessary. Average recoveries of cyprodinil were found in the range of 82.92-107.43% with relative standard deviations of 2.48-14.55%. The pesticide cyprodinil showed a relatively fast decline rate. The half lives were from 2 to 4 days in leek and pepper, from 2-5 days in soil except in Beijing (14.7 days). So the decline of cyprodinil in leek and pepper was almost same in different experiment plots. However, the decline in soil was much complicated, and affected by the precipitation and other climate condition. The results could provide guidance to safe and reasonable use of this pesticide in agriculture.

Molecular Characterization and Pathogenicity of Infectious Bronchitis Coronaviruses: Complicated Evolution and Epidemiology in China Caused by Cocirculation of Multiple Types of Infectious Bronchitis Coronaviruses

Objective: To monitor and study the molecular epidemiology, evolution and pathogenicity of infectious bronchitis viruses (IBVs) in China in recent years and further our knowledge of the evolution of IBVs. Methods: Thirty-seven IBV isolates were isolated from commercial chickens in China. The isolates were characterized by RT-PCR, sequencing, typing and analyzing the entire S1 gene. In addition, 4 selected IBV isolates were used to experimentally infect the specific pathogen-free chickens to study their pathogenicity. Results: Three types of IBV have been cocirculating in chicken flocks in China in recent years. Unique insertions and deletions in S1 protein regions were identified among different types of IBV. Moreover, a new IBV strain was isolated and identified in a layer hen. S1 gene analysis showed that a recombination event had occurred in the virus’s evolutionary process. In addition, experimental infection has shown that IBV isolates have been nephropathogenic in China in recent years. Conclusion: Mutations, insertions, deletions and recombination of the S1 protein gene contribute to the genetic diversity of IBV in China. Cocirculation of multiple types of IBV in field conditions in China renders its epidemiology and evolution very complicated, indicating the necessity for development of new vaccines or vaccine strategies.

Free and bound phenolic compounds in leaves of pak choi (Brassica campestris L. ssp. chinensis var. communis) and Chinese leaf mustard (Brassica juncea Coss)

Eleven pak choi cultivars and two leaf mustard cultivars grown under field conditions in China were investigated for the free polyphenol content in their outer and inner leaves, as well as in their leaf blades and leaf stalks. In most cases, there were no significant differences between the hydroxycinnamic acid derivative and flavonoid derivative contents in the outer and inner leaves for the 13 cultivars. However, the contents of blades and stalks differed: hydroxycinnamic acids and flavonoids were present in greater amounts in the leaf blade than in the leaf stalk. Trace or small amounts of flavonoids were detected in the pak choi and leaf mustard stalks. Additionally, the bound phenolic contents of two pak choi cultivars and two leaf mustard cultivars were investigated. The concentrations of cell wall-bound phenolic compounds were higher in the leaf blade than in the leaf stalk under field conditions in China. These compounds represent only a minor portion of the total phenolic contents (flavonoids and hydroxycinnamic acids) in leaf stalks (0.81–1.18%) and leaf blades (0.05–0.08%) from fresh plant material. The storage of plant samples from four Chinese cabbage cultivars resulted, in most cases, in an increase of phenolic content, within six days, at 4°C and 20°C. The increase might have been triggered by post-harvest plant stresses, which stimulate the biosynthesis of polyphenols.

Expression of Bt cry1Ac in transgenic oilseed rape in China and transgenic performance of intraspecific hybrids against Helicoverpa armigera larvae

The expression of a synthetic Bacillus thuringiensis (Bt) cry1Ac gene in oilseed rape (OSR, Brassica napus) was monitored under field conditions in China, and performance against Helicoverpa armigera larvae was compared in intraspecific hybrids with a Chinese OSR variety. Leaf samples from transgenic OSR were collected at various developmental stages in two separate field experiments. The Bt Cry1Ac concentrations in the third uppermost leaves increased before pod formation stage and either increased or decreased after pod formation stage whereas the total soluble protein increased before and decreased after pod-fill in the later growing season. Spontaneously formed intraspecific hybrids between transgenic OSR and a Chinese conventional OSR were obtained in the field and transgenic status was confirmed by a green fluorescent protein (GFP) phenotype and polymerase chain reaction. A bioassay on the neonate larvae of a susceptible strain of H. armigera was performed to test the efficacy of Bt Cry1Ac toxin in hybrid OSR plants. Both the original transgenic OSR and hybrid plants had a negative effect on body-weight gain of insect larvae. It was assumed that Bt Cry1Ac toxin concentration was similar in hybrids compared to the original transgenic OSR at the investigated developmental stages. The frequency of hybrid production and volunteerism could potentially enhance the evolution of insect pest tolerance in the field.