Interrelationship Between Biomass and Architecture during Growth in Setaria

Development of plant architecture in grasses is a complex process that happens throughout the lifespan of the plant. The final architecture results from the interplay of genetic, developmental & environmental factors. We have evaluated several plant architectural characters and biomass in a set of recombinant inbred lines developed from a cross between the domesticated cereal foxtail millet (Setaria italica) and its wild progenitor green foxtail (S. viridis).  We analyzed the genetic regulation of plant architecture and biomass at both flowering and harvest stages, at two different planting densities.  We find a conserved regulation of flowering time, height, and biomass, but great variation in branching patterns.  Further analysis of candidate genes underlying QTL regions is expected to reveal how both developmental genetics and environmental responses (plasticity) contribute to adaptation to varying environmental regimes throughout growth.