CultivarRateParams

A data model that stores vernalisation rate parameters for a specific cultivar. These parameters are used within APSIM NG’s CAMP model to simulate the temperature and photoperiod sensitivity of flowering development in cereals such as wheat and barley.

Overview

The CultivarRateParams class defines a set of vernalisation-related parameters tailored to a single genotype or cultivar. These values quantify the rates and thresholds for vernalisation gene expression (e.g., Vrn1, Vrn2, and Vrn3) under different photothermal conditions.

It is not a computational function itself but a container of parameters used by other modules like CalcCAMPVrnRates to describe how vernalisation proceeds under varying temperatures and daylengths. It supports detailed phenological simulations in APSIM NG’s CAMP framework.

Inputs

This model is not user-configurable directly through the UI and does not require inputs at runtime. Instead, it is populated by the CalcCAMPVrnRates function based on controlled environment FLN observations.

Methodology

CultivarRateParams provides the following fields, which represent physiological and regulatory coefficients used to simulate flowering development:

  • BaseDVrnVeg (\(\Delta V_{\text{base, veg}}\)): Baseline rate of vernalisation gene expression (Vrn1) in the vegetative phase at high temperatures (e.g., >20°C).
  • MaxDVrnVeg (\(\Delta V_{\text{max, veg}}\)): Maximum upregulation of Vrn1 under cold conditions (e.g., 0°C).
  • BaseDVrnER (\(\Delta V_{\text{base, ER}}\)): Baseline rate of Vrn1 expression during early reproductive phase without photoperiod upregulation.
  • MaxDVrnER (\(\Delta V_{\text{max, ER}}\)): Maximum rate of Vrn1 expression during early reproductive phase under long photoperiod.
  • PpVrn3FactVeg (\(F_{\text{Pp, Vrn3, veg}}\)): Enhancement factor for Vrn1 expression in vegetative phase due to Vrn3 upregulation under long days.
  • PpVrn3FactER (\(F_{\text{Pp, Vrn3, ER}}\)): Enhancement factor for Vrn1 expression in early reproductive phase due to Vrn3 under long days.
  • MaxVrn2 (\(V_{\text{max, Vrn2}}\)): Maximum Vrn2 expression level under long photoperiods, which must be suppressed before full Vrn1 expression can proceed.
  • MethalationThreshold (\(M_{\text{threshold}}\)): Threshold level of cold-induced Vrn1 expression needed to enable persistent Vrn1 activation (methalation).
  • ColdVrn1Fact (\(C_{\text{Vrn1}}\)): Factor by which cold temperatures increase the rate of Vrn1 expression compared to the baseline.

These parameters are essential for simulating genotype × environment interactions that influence time to floral initiation and flowering in cereal crops.

Events

Events Listened For

No events are listened by this function.

Events Raised to

No events are raised by this function.

Properties

Configurable and Reportable Properties

Property Type Description
BaseDVrnVeg double Baseline Vrn1 expression rate in vegetative phase (>20°C)
MaxDVrnVeg double Max Vrn1 expression rate at 0°C during vegetative phase
BaseDVrnER double Baseline Vrn1 expression rate in early reproductive phase
MaxDVrnER double Max Vrn1 expression rate in early reproductive phase under long day
PpVrn3FactVeg double Relative increase in Vrn1 expression by Vrn3 in vegetative phase
PpVrn3FactER double Relative increase in Vrn1 expression by Vrn3 in early reproductive phase
MaxVrn2 double Maximum expression of Vrn2 in long days
MethalationThreshold double Cold requirement before persistent Vrn1 expression occurs
ColdVrn1Fact double Relative cold-induced increase in Vrn1 expression

Read-Only Reportable Properties

No read-only properties are available for this function.

User Interface

Not typically user-configurable through the UI. It is populated by the CalcCAMPVrnRates function based on genotype-specific FLN observations.

Practical Example

No practical example is available for this function.

See Also