谷子抗除草剂基因从栽培种向其近缘野生种漂移的研究

Gene Flow from Cultivated Herbicide-resistant Foxtail Millet to its Wild Relati ves: a Basis for Risk Assessment of the Release of Transgenic Millet

作物同种及栽培种与近缘野生种之间的基因漂移 (基因流 )是防范作物品种生物学混杂及评估转基因新种质田间释放后所产生的生态学效应的重要基础参数。本研究以显性抗除草剂 (拿捕净 )谷子种质作为花粉供体材料 ,以青狗尾草作为花粉受体材料进行了栽培种向其主要近缘野生种基因漂移的检测研究。研究结果表明 ,尽管一般认为谷子及其近缘野生种是自花授粉植物 ,栽培谷子的性状基因仍可向周围 60 m范围内的青狗尾草漂移 ,其基因流的频率随着距花粉供体中心距离的增加而递减 ,花粉供、受体植株相邻 0 .0 3m时基因流频率最高 ,平均达 1.14%,基因流锐减的陡坡发生在 0 .5 m以内 ,与花粉供体植株相距 2 0 m时基因流频率开始趋向于零 ,但某些方向 60 m时仍可检测到基因漂移。气候因素中影响基因流频率高低的主要因素是风 ,在本试验条件下顺、逆风基因漂移的频率相差 2倍多。

Gene flow within cultivated ( cv) populations, and between cv and its w ild relatives is a key issue of the bio contamination and the potential risk of the use of transgenic crops. The test of gene flow between cultivated population of foxtail millet ( Sataria italica) and its wild relative, green foxtail (S.viridis) was carried out in the field, using a dominant setho xydim resistant lin e as a pollen donor and a population of green foxtail as a recipient. The results showed that although it is well known that two species are autogamous, the polle n from a 10 m diameter plot could fertilize the green foxtail up to 60 m. The hi ghest frequency of gene flow was at 0.03 m, reached 1.14 % in average. The frequ ency decreased with distance increase. A sharp decrease of the frequency took pl ace within 0.5 m from pollen donor plant. Generally, the frequency of gene flow became 0 at 20 m, but it was possible that pollens dispersed from pollen donor s ources up to 60 m in some cases. The wind direction is the major climate factor influencing the frequency of gene flow. There was two times difference in freque ncy under two contrasting directions of wind.