To know a plant, grow a plant!
After ten days of growth, we decided to conduct our selection on the metric of plant height. Due to the process of bolting (rapid extension of the stem prior to flowering), our selection could become biased if we selected based on the heights of the plants at only day 10, because bolting was beginning in some plants. To avoid this bias, we calculated which plants were in the 90th percentile for height (the top 10% of tallest plants) for every day that we were able to obtain data. The plants that were in the 90th percentile most often were selected for and all other plants were removed and fed to our employer's chickens.
Please see this link for a representation of plants that fell into the 90th percentile for height.
After this process, we were left with thirteen plants from which we will collect seed and raise our next generation.
Here is a link for the photo of the tallest plants at Day 14.