Adugna Asfaw, Sweeney Patty M, Bekele Endashaw
Department of Biology, Addis Ababa University, Addis Ababa, Ethiopia.
J Genet. 2013 Apr;92(1):3-10. doi: 10.1007/s12041-013-0214-6.
Because transgenic sorghum (Sorghum bicolor L.) is being developed for Africa, we investigated the potential for transgenes to spread to conspecific wild/weedy sorghum populations in Ethiopia, which is considered the centre of origin of cultivated sorghum. In the current study, the extent of outcrossing, and uniparental and biparental inbreeding were investigated in seven wild/weedy sorghum populations collected at elevations ranging from 631 to 1709 m. Based on allele frequency data of 1120 progenies and 140 maternal plants from five polymorphic microsatellite markers, outcrossing rates were estimated using standard procedures. The average multilocus outcrossing rate was 0.51, with a range of 0.31-0.65 among populations, and the family outcrossing rate was in the extreme range of 0 to 100%. The highest outcrossing (t(m) = 0.65) was recorded in a weedy population that was intermixed with an improved crop variety in Abuare (Wello region). It was also observed that the inbreeding coefficient of the progenies (F(p)) tend to be more than the inbreeding coefficient of both their maternal parents (F(m)) and the level of inbreeding expected at equilibrium (F(eq)), which is a characteristic of predominantly outbreeding species. Biparental inbreeding was evident in all populations and averaged 0.24 (range = 0.10-0.33). The high outcrossing rates of wild/weedy sorghum populations in Ethiopia indicate a high potential for crop genes (including transgenes) to spread within the wild pool. Therefore, effective risk management strategies may be needed if the introgression of transgenes or other crop genes from improved cultivars into wild or weedy populations is deemed to be undesirable.
由于正在为非洲培育转基因高粱（Sorghum bicolor L.），我们研究了转基因扩散到埃塞俄比亚同属野生/杂草高粱种群的可能性，埃塞俄比亚被认为是栽培高粱的起源中心。在当前研究中，对在海拔631至1709米范围内采集的七个野生/杂草高粱种群的异交程度以及单亲本和双亲本近亲繁殖情况进行了调查。基于来自五个多态性微卫星标记的1120个后代和140个母本植株的等位基因频率数据，使用标准程序估算异交率。平均多位点异交率为0.51，种群间范围为0.31 - 0.65，家系异交率在0至100%的极端范围内。在阿瓦雷（韦洛地区）与改良作物品种混生的一个杂草种群中记录到最高异交率（t(m)=0.65）。还观察到后代的近亲繁殖系数（F(p)）往往高于其母本的近亲繁殖系数（F(m)）以及平衡时预期的近亲繁殖水平（F(eq)），这是主要进行异交繁殖物种的一个特征。双亲本近亲繁殖在所有种群中都很明显，平均为0.24（范围 = 0.10 - 0.33）。埃塞俄比亚野生/杂草高粱种群的高异交率表明作物基因（包括转基因）在野生种群中扩散的可能性很高。因此，如果认为转基因或其他作物基因从改良品种渗入野生或杂草种群是不可取的，可能需要有效的风险管理策略。
