At 32 days after planting, the wild species (Setaria viridis, A10.1, green foxtail) takes a commanding lead in life cycle over the domesticated crop (Setaria italica, foxtail millet).
But don’t despair, you fans of working with domesticated species: Foxtail millet still have a good chance of taking the lead in the generations per year game. After they are harvested seeds from that green foxtail plant won’t be ready to germinate for months, while the foxtail millet seeds can be planted as soon as they are mature enough to harvest.
So I’m now confident the Setaria photo in the last post was yellow foxtail (Setaria pumila). One of the key diagnostic criteria is the larger spikelets of yellow foxtail relative to green foxtail (Setaria viridis), which sounds fine on paper, but you need a reference point to compare against. Now I have one. This is either Setaria viridis or Setaria faberi* but either way you can see the much smaller spikelets than yellow foxtail.
*From the description of Setaria faberi “Characteristic foxtail-like seedhead that droops when mature and leaves with many hairs on the upper leaf surface, which helps to distinguish this weed from both Green Foxtail (Setaria viridis) and Yellow Foxtail (Setaria glauca**). Giant foxtail may be identified by the presence of many short hairs on the upper surface of the leaf blades, unlike the other foxtails.”
Source: Division of Plant Biology, University of Missouri: http://weedid.missouri.edu/weedinfo.cfm?weed_id=256
Today’s innovation was figuring out how to manually set the exposure/AEB setting on the camera so images didn’t look frightening washed out when photographed against a traditional black background.
So here’s today’s procrastination figure:
Of course we really should compare to the wild progenitor, Seteria viridis (Green foxtail). Unfortunately, our Setaria viridis isn’t flowering the greenhouse yet. Fortunately, my tomatillo batch at home is prone to weeds. Unfortunately, I’m not enough of a botanist to code this plant out beyond the genus level. The image below is either Setaria viridis (the direct progenitor of Setaria italica), or (according to the list of grasses native to Nebraska) it could be Setaria faberi, Setaria pumila or Setaria verticillata. I’m reasonably confident it isn’t S. faberi or S. verticillata but S. pumila (Yellow foxtail) is a real possibility. Actually, the more I read about it the more I think this is Setaria pumila given the largish spikelets and tan color of the bristles.
Study of the S. viridis clade also needs to include S. pumila (Poir.) Roem. & Schult., a common weed that often grows in mixed populations with S. viridis and its relatives. Although it appears to be of African origin (Rominger, 2003) and is not closely related to S. viridis in phylogenies (Doust et al., 2007; Kellogg et al., 2009), the ecological preferences of S. pumila are similar to S. faberi and S. viridis (hereafter collectively the “S. viridis clade”).*
So just a tiny bit of DNA sequencing would answer my question once and for all….
In the meantime, I’ll just have to wait for our validated S. viridis plants to flower. Currently twenty one days after planting.
*Daniel J. Layton and Elizabeth A. Kellogg “Morphological, phylogenetic, and ecological diversity of the new model species Setaria viridis (Poaceae: Paniceae) and its close relatives” Am. J. Bot. March 2014 101:539–557 doi: 10.3732/ajb.1300428
Remember how similar grass species look prior to flowering? Flowering is a whole different story. Here’s a couple of nice pictures we took in lab this week now that we’re no longer constrained by the use of cell phone cameras. (Click to zoom in to a ridiculously high resolution.)
If I am lucky our Paspalum vaginatum will flower sometime in September. Until them I’ll continue to use this blurry iPhone photo.