Figure 6.

ABC SMC allows selection of competing mechanistic models for root growth. (a) Model selection posteriors from comparing a simple, constant-rate growth model to the negative-exponential model used in CRootBox [29] for decreasing ABC tolerance ε. The negative-exponential model acquires greater support as the tolerance decreases. (b) Model selection posteriors from comparing a uniform branching model to a model imposing a minimum separation from existing branches. The more parsimonious uniform model experiences higher support with relaxed tolerance but the minimum-separation model gains support with tighter tolerances (tolerances are higher for this model selection run, reflecting a tradeoff with the greater computational resource required). (c) Posterior for the minimum branch separation, δ, required when the minimum spacing model is implemented. (Online version in colour.)