Agricultural adaptation in the native North American weed waterhemp, Amaranthus tuberculatus (Amaranthaceae)

There is increasing interest in documenting adaptation of weedy plant species to agricultural ecosystems, beyond the evolution of herbicide resistance. Waterhemp (Amaranthus tuberculatus) is a native plant of the Midwestern U.S. that began infesting agricultural fields in the 20th century within the central portion of its range. We hypothesized that the vegetative growth and reproductive traits of waterhemp from this heavily infested central region provide differential fitness benefits in agricultural environments. We collected seeds from across the species’ native range, representing regions with varying degrees of waterhemp infestation, and planted them together in common garden soybean plots. A 2010 common garden experiment was conducted within the range of agriculturally weedy waterhemp (in Missouri), and a 2011 common garden experiment was conducted outside of this range (in Ohio). Days to flowering and flowering plant height, mature plant size data (height, number of branches, and...

除除草剂抗性演化外，学界对记录杂草植物物种适应农业生态系统的研究兴趣与日俱增。瘤果苋（Waterhemp, Amaranthus tuberculatus）是美国中西部本土植物，自20世纪起便开始在其分布范围的中部区域侵染农田。我们提出如下假说：来自侵染严重的中部区域的瘤果苋，其营养生长与生殖性状可在农业环境中带来差异化的适合度收益。我们从该物种的整个本土分布范围内采集种子，覆盖了瘤果苋侵染程度各异的区域，并将这些种子共同种植于大豆田的共同花园试验地块。2010年的共同花园试验在农业杂草型瘤果苋的分布范围内（美国密苏里州）开展，而2011年的共同花园试验则在该范围之外（美国俄亥俄州）进行。试验测定的性状包括开花天数、开花期株高，以及成熟植株的形态数据（株高、分枝数，以及……