抗旱转基因小麦(Triticum aestivum L.)的杂草性评价

Safety Assessment of Weediness of Transgenic Drought-Tolerant Wheat(Triticum aestivum L.)

【目的】全球转基因作物商业化迅猛发展,包括杂草化在内的一系列生态风险评估和研究尤为重要。文章中系统评价抗旱转基因小麦MGX-L大面积推广种植可能带来的演化为杂草的生态风险,为转基因抗旱小麦的环境安全评价标准制定提供科学依据。【方法】通过比较荒地和栽培地上抗旱转基因小麦、受体小麦和当地常规品种的农艺性状,评价转基因小麦的生存竞争能力;并比较荒地上生存的转基因小麦与受体的繁殖系数,评价转基因小麦群体在野外的生存能力。比较转基因小麦和受体品种的自生苗比率、种子落粒性、及深埋和浅埋地下种子萌发情况,评价转基因小麦的自然延续能力。比较转基因小麦和受体品种的花粉活力、花粉大小和花粉育性,评价转基因小麦的自然繁育能力。综合分析以上各项评价结果,评价抗旱转基因小麦演变为杂草的可能性。【结果】转基因小麦在栽培地上种植,其株高、总穗数和穗粒数与受体品种相比,没有显著差异,而转基因小麦的产量、千粒重显著高于受体品种。但和其他非转基因当地主栽小麦品种相比,或没有显著差异,或低于其他非转基因小麦品种,因此,转基因小麦与其非转基因小麦对照相似,在栽培地种植没有更强的生存竞争能力。在荒地环境下,转基因小麦生存竞争能力和受体品种没有显著差异。在荒地上种植且成熟的转基因小麦,单位面积内收获的总籽粒数少于上一年种下的种子粒数,其繁殖系数低于1。转基因小麦群体不可能在野外环境中自然维持下去。转基因小麦种子的落粒性和产生自生苗比率与受体品种相比没有显著差异。深埋20 cm以下土层的转基因小麦和受体品种的种子全部腐烂;浅埋3 cm土层的转基因小麦和受体品种的种子或者腐烂或者出苗,没有发现未萌发且保存完好能够保持活力继续发芽的种子,二者的种子腐烂或出苗的比率没有显著差异,说明转基因小麦和受体品种种子的延续能力低且无显著差异。【结论】转基因抗旱小麦MGX-L与其受体对照品种济麦22及其他非转基因当地主栽品种相似,耐旱性状的引入不会增加小麦的杂草化潜势。

【Objective】 Genetically modified（GM） plants have been widely used in both agriculture and food industry.A scientifically sound environmental risk assessment,including weediness risk,is required for crops derived from genetically modified prior to unrestricted release into the environment.The objective of this study was to assess the potential ecological risk for weediness of transgenic drought-tolerant wheat MGX-L,and to provide scientific data for the formulation of evaluation standard of environmental safety assessment of transgenic wheat in China.【Method】 In the cultivated lands and abandoned lands,the surviving competition ability of transgenic drought-tolerant wheat MGX-L,recipient variety and conventional wheat varieties were comparatively evaluated by investigating their agricultural traits.The propagation coefficient of wheat planted in abandoned lands was compared and the survival ability in abandoned lands was evaluated.Volunteer possibility,seed shattering and persisting possibility of transgenic drought-tolerant wheat MGX-L were analyzed and compared with the wild type for evaluating the ability of life continuous.The reproducing ability was evaluated by comparing the pollen viability,pollen diameter and sterility of MGX-L with the wild type.The weediness potential of MGX-L was evaluated based on the above results.【Result】There were no significant differences between transgenic wheat MGX-L and the wild type in plant height,spike number per hectare and per spike grain.The 1000-grain weight and yield of the transgenic wheat MGX-L were higher than that of the recipient variety Jimai 22.However,the 1000-grain weight and yield of the transgenic wheat MGX-L were lower than that of conventional wheat varieties or no significant difference.There were no significant differences between transgenic wheat MGX-L and the wild type in survival ability in the cultivated lands.Some wheat seeds could geminate and obtain seeds of next generation in abandoned lands.However,its propagation coefficient was less than 1 and the population size of transgenic wheat declined after the first year as a result of increased competition from native perennial plants.The transgenic wheat population couldn＇t persist in abandoned lands like its conventional counterpart.There were no significant differences in seed shattering ability and volunteer plants rate between the transgenic wheat and the wild type.When buried under soil 20 cm,the seeds of transgenic wheat and the wild type were all rotted.When buried under soil 3 cm,the seeds of transgenic wheat and the wild type were rotted or sprouted.There were no intact seeds buried under soil.So there was no significant difference between the transgenic wheat and the wild type in seed persisting ability.【Conclusion】 It was concluded that the transgenic drought-tolerant wheat MGX-L had the lowest potential weediness like the non-transgenic wheat varieties,based on the assessment of survival ability,seed shattering ability,volunteer plants rate and seed persisting ability.