Table 2.
Strategy parameters: model parameters determining dynamic development of root structure, with description, units (where relevant) and the value used in this study to define the base genotype from which the initial population is generated; these parameters ‘evolve’ during evolutionary simulations
| Model parameter | Description* | Units | Value |
|---|---|---|---|
| wt0 | The initial lateral root growth weighting | – | 0·1 |
| wtΔ | The rate at which the lateral root growth weighting changes down the main root | – | 0·05 |
| wtvar | The random variability in lateral root growth weighting | – | 0·001 |
| θgr | Gravitropism parameter | – | 0·99 |
| θvar | Variability in vertical growth direction | radians | 0·02 |
| pdownmax, bdown, adown | Parameters determining probability of normal lateral root branching | See text | 0·5; –0·1; 50 |
| delay | Delay before lateral branching begins | days | 10 |
| pupmax, bup, aup | Parameters determining probability of lateral root branching triggered by main root encountering impermeable layer | See text | 0·8; –0·1; 50 |
| θbranch | Branching angle of lateral roots | radians | π/4 |
| φph | Phyllotactic angle | radians | π/2 |
| pshbmb, pshbma | Proportion of biomass allocated to shoot before/after a wet crack is encountered | – | 0·1; 0·1 |
*Further details in text.