Table 1.
Hypothetical selective pressures on annual plants associated with seed-saving and planting.
Fig 1.
Fruit (achene) dimorphism in erect knotweed: A) thick, tubercled pericarp morph fruit (achene) that is >80% dormant after 6 weeks of cold, moist stratification; B) thin, smooth pericarp morph fruit (achene), which is >50% non-dormant after 6 weeks of cold, moist stratification, and; C) pericarp cross-sections, showing relative thickness of the pericarp, which restricts germination by preventing moisture from reaching the seed.
Table 2.
Harvest date, plant density and frequency of thin pericarp morphs in erect knotweed harvests Free-living parent populations are shaded.
Fig 2.
A) A typical senesced plant, example from the 2020 experiments, harvested at Tyson Research Center, MO, on October 23; B) a typical high-density stand of senescing, free-living erect knotweed along a dirt farm road, Big River, MO, October 22, 2014; C) 2018a experiment on October 30, shade treatment used in 2016 and 2018b experiments in background, and; D) an example of a plant that was harvested before senescence because heavy snow fall was predicted, 2019 experiment, November 15.
Fig 3.
Examples of differences in plant size and architecture between typical individual free-living (inset) and experimental erect knotweed plants.
Images are to scale.
Fig 4.
Correlation between the percent thin pericarp morphs in the harvest and the harvest date with line of best fit.
Points within the shaded area are outside the range of variation documented for free-living erect knotweed.
Fig 5.
Correlation between the percent thin pericarp morphs in the harvest and plant density with line of best fit.
Points within the shaded area are outside the range of variation documented for free-living erect knotweed.