EarlyGrainFilling
The EarlyGrainFilling phase in Chickpea represents the developmental period from EndPodInitiation to MidGrainFilling. This phase marks the beginning of the grain filling period when seeds start to accumulate dry matter rapidly.
Overview
The GenericPhase model simulates the time between EndPodInitiation and MidGrainFilling stages.
- This phase starts at EndPodInitiation and ends at MidGrainFilling
- The model uses daily Thermal Time, retrieved from the
[Phenology].ThermalTimefunction - The Target thermal time is cultivar-specific
Early Grain Filling Process
During early grain filling:
- Seeds begin rapid accumulation of starch, protein, and other reserves
- Grain filling rate is typically highest during this phase
- Seeds increase in size and weight substantially
- Assimilate demand by grains is very high
- Source-sink relationships strongly influence grain growth
Target Thermal Time
The target thermal time for this phase is dynamically adjusted based on the duration of the Pod Initiation phase:
\[ \text{Target} = T_{\text{max}} - \frac{TT_{\text{PodInit}}}{2} \]
Where: - \(T_{\text{max}}\) = Maximum early grain filling duration (300 °Cd by default) - \(TT_{\text{PodInit}}\) = Total thermal time accumulated during the Pod Initiation phase
\(\text{Target}\) is capped at zero to prevent negative durations.
Cultivar-Specific Parameters
| Name | Description | Default Value |
|---|---|---|
| [Phenology].EarlyGrainFilling.Target.Reducer.Max | Maximum thermal time for early grain filling (°Cd) | 300 |