SP6: Integrating Genetics into Crop Growth Models to Understand Genotype Response to Combined (Abiotic + Biotic) Stresses & Synthesis of Modelling

SP6 develops a novel process-based crop model — the MultiStress model — that simulates how different maize genotypes perform under combined abiotic and biotic stresses. By linking genetic information (QTLs) to ecophysiological model parameters, SP6 bridges the gap between genomics and field-scale crop prediction, enabling in silico evaluation of genotype × environment interactions under climate change.

Project description

Main research questions:
SP6 addresses the central question: How can genetic information be integrated into crop growth models to predict genotype-specific responses to combined abiotic (drought, nitrogen deficiency) and biotic (stem borer herbivory, Setosphaeria turcica foliar disease) stresses in maize? Starting from the base crop model SSM-iCrop, SP6 builds a new MultiStress crop model by incorporating biotic stress routines developed in SP4 and SP5, and linking QTL data from SP3 to ecophysiological crop parameters.

Methods applied:
Process-based crop simulation modelling, sensitivity analysis of the model, QTL-to-parameter mapping, and multi-environment calibration/validation using 12 commercial maize hybrids (6 tropical, 6 temperate) grown across the Research Unit’s (RU’s) Central Experiment.

Flowchart illustrating carbon allocation in a maize plant, showing pathways from photosynthesis to respiration, storage, root exudates, and interactions with herbivores, pathogens, and soil processes—key aspects for food security and ecophysiology. — Schematic of the envisaged new *MultiStress crop model* | Hoffmann/Köster 2026

Expected outcomes:

A validated modelling platform that simulates yield under multiple interacting stressors,
demonstrated proof-of-concept for QTL-informed parameterisation beyond phenology,
simulation-based testing of the RU’s core hypotheses on non-additive stress interactions and impact severity differences between tropical and temperate environments, and
ex ante identification of promising genetic trait combinations and environmental stress scenarios to guide the experimental design of the RU’s Phase 2.
SP6 thus provides the integrative synthesis framework that connects all subprojects of the RU.