Dissertation
Dissertation > Agricultural Sciences > Plant Protection > Harmful plants and their removal > Weeds

Risk Assessment of Gene Flow from Herbicide-Resistant Genetically Modified Rice and Oilseed Rape Respectively to Weedy Rice and Wild Brown Mustard under Artificial Cultural Conditions Through Ecological Fitness

Author WangZhou
Tutor QiangSheng
School Nanjing Agricultural College
Course Developmental Biology
Keywords Transgenic rice (Oryza sativa) The transgenic oil Levin (Brassica napus) Weedy rice (Oryza sativa f. Spontanea) Wild mustard (Brassica juncea var. Gracilis Tsen et Lee) Fitness Genetic drift Introgression of genes Safety Evaluation Hybridization Backcross
CLC S451
Type Master's thesis
Year 2007
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Herbicide-resistant transgenic crop field release of one of the ecological problems caused by the resistance gene drift through gene flow to wild / weed related species, which pose a threat to the local biodiversity. Therefore, before the release of their potential risk assessment is essential. Pollen-based gene drift of genetically modified crops and wild / weed related species hybrid, backcross, and continued in this way produce offspring fitness. Wild / weed related species ability to survive in the habitat settlers resistance gene depends on its ecological fitness. Studied under greenhouse conditions, that is, from the point of view of fitness of herbicide-resistant transgenic rice (Oryza sativa) and weedy rice (O.sativa f.spontanea) the hybridized rapeseed (Brassica napus) and wild the mustard (B.juncea var. gracilis Tsen et Lee) backcross resulting offspring carrying the resistance gene in two phases on nutrition, reproductive performance. Analysis of their fitness and compared to the respective wild / weed related species differences, in order to evaluate its success to the possibility of genetic drift. Suitable degree of two different transgenic crops and future ecological research helps comparison reveals the goodness of fit in the universal significance of the safety evaluation of genetically modified crops. Weeds in rice hybrid offspring F main research content of this paper and the results are as follows: 1. Accept genetically modified rice herbicide resistance gene 1 F 2 ecological fitness to two anti-glufosinate transgenic rice Y0003 ,99-4, t, and three types of weedy rice AH, share177 hybrid from the carry resistance genes progeny F 1 F 2 for the study of these offspring fitness components, including plant height, tillers number, stem diameter, leaf length, leaf width, flag leaf area, net photosynthetic rate and other nutrition indicators; pollen viability, individual panicles of spikelets / inflorescence, bagged outcrossing rate, the shattering rate spike length, grain length, grain width, grain thickness, kernel weight and other reproductive indicators. The results show that the 4 × YF 1 , Y × ? F 1 total fit respectively 1.12,1.1-transgenic Y0003 1.2 was no significant difference, but obviously high weedy rice parents on the 4th; 4 × YF 2 Y x 4 F 2 total fitness were 1.02,1.04, all this weedy rice pro 4 No significant differences. visible, F 2 suitable ratio F 1 decreased slightly, but close to the level of weeds Rice Parents. other words, F < sub> 1 , F 2 with similar or even slightly higher survival weedy rice competitiveness. Therefore, to the success of weedy rice resistance gene drift caused by the risk of genetic pollution can not be underestimated. Characteristics of weedy rice parents a great impact on the performance of hybrid offspring, direction by hybrid and transgenic rice genotypes. The hybrid generation also has the formation from seedlings potential. 2 the weedy rice Hybrid Progeny F to accept genetically modified rice herbicide resistant gene 2 , F 3 's ecological fitness of comparing two anti-grass phosphinothricin transgenic rice Y0003 No. 4 ,99-t, and two types of weedy rice AH hybridization resulting carry resistance genes progeny F 2 F 3 as the research object, research These offspring fitness components, including plant height, number of tillers per plant, stem diameter, leaf length, leaf width, flag leaf area, aboveground biomass, chlorophyll fluorescence parameters Fv / Fm nutrition indicators; pollen viability per plant, number of panicles, spikelet / inflorescence, bagged outcrossing rate, the shattering rate spike length, grain length, grain width, grain thickness, kernel weight and other reproductive indicators. The results show that the terms corresponding weeds Rice in total fitness value as a standard for comparison \reach 0.93,0.95, AH × YF 2 F 3 's were 0.94,1.02,4 × 99-t F 2 , F < sub> 3 's as 0.98,1.04 AH × 99-t F 2 F 3 0.92,0.99 their weedy rice parents no significant differences. F 3 fitness is not reduced, maintained at a similar level to its weedy rice parents, has strong competition for survival and, therefore, to the success of weedy rice resistance gene drift occurs causing gene the risk of contamination should not be underestimated. Characteristics of weedy rice parents a great impact on the performance of hybrid offspring, direction by hybrid and transgenic rice genotypes. The hybrid generation also has the formation from seedlings potential. Accept the the wild mustard backcross second generation of the genetically modified oilseed rape herbicide-resistant gene, backcrossed three generations and backcross second generation sub-generation the ecological fitness glufosinate and glyphosate-resistant transgenic oilseed rape and wild mustard backcross obtained carrying the resistance gene backcross second generation backcross three generations of backcrossing second generation sub-generation study, these offspring fitness components in a single species, double, mixed three cropping patterns, including bolting stage per plant, plant height, number of branches per plant, stem diameter, rosette diameter, chlorophyll fluorescence parameters Fv / Fm nutrition indicators; flower number, pollen viability, pod number per plant, pod length, pod full grains per pod seed rate, seed weight and other reproductive indicators. The results show that, through the continued infiltration of constantly backcross wild mustard gene, will back the account total fitness back to the level of the recurrent parent wild mustard. This means that they are on their own under natural conditions the possibility to complete its life cycle is greatly threatened around the Brassica plant diversity of wild relatives. But under the conditions of this experimental design, reverse backcross, planting the impact on the total fitness value is smaller. Backcross also has the potential to form a self-seedlings. 4 the wild mustard backcross second generation of the second generation to accept genetically modified oilseed rape herbicide-resistant gene, backcrossed three generations of first generation and backcrossed four generations of ecological fitness glufosinate and resistance to glyphosate in genetically modified oilseed rape and wild mustard back the cross carrying resistance genes from the the backcross second generation of the second generation, backcross three generations of first generation backcross four took the study of these offspring fitness components in a single species, double, mixed three cropping patterns, including bolting, plant height, number of branches per plant, stem diameter, the diameter of the rosette, aboveground biomass and other nutrition indicators; flowering, pod number per plant, pod length, full grains per pod, each pod seed setting rate and reproductive indicators. The results show that, through the continued infiltration of constantly backcross wild mustard gene, will back the account total fitness back to the level of the recurrent parent wild mustard. This means that they are on their own under natural conditions the possibility to complete its life cycle is greatly threatened around the Brassica plant diversity of wild relatives. Our results also show that the reverse backcross, planting a certain extent affect the total for the size of the value. In summary, its wild / weed parents because of the viability of hybrid or backcross progeny comparable, herbicide-resistant transgenic rice and rapeseed gene flow to weedy rice and wild mustard does not exist on the fitness obstacles. And the the seed offspring knot has become a potential risk from seedlings. Light of these risks, the large area field promotion needs careful consideration, as far as possible to take effective measures to prevent the occurrence of genetic pollution.

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