Maize Drought Tolerance via APSIM Regression Slope

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Solution Overview

Problem

Current methods for determining drought stress tolerance in crops are complex and lack a reliable, economically viable approach, particularly for maize production, as they fail to account for the variability in drought timing, duration, and severity across different environmental conditions.

Innovation Solution

A method involving multiple field trials across geographically separated locations to compute a linear regression between grain yield and stress index, using environmental parameters like soil water deficit, vapor pressure deficit, and heat stress, to determine drought tolerance, which is represented by the slope of the regression, with a more tolerant plant line having a slope closer to zero.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional phenotyping methods are used to assess drought stress tolerance, then breeding can identify tolerant genotypes, but the process is extremely time-consuming and requires large trial networks across multiple locations and years

Engineering Contradiction:
Improvedrought tolerance determinationVSAvoidbreeding evaluation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces complex mechanical phenotyping systems (large field trial networks, multiple locations, yearly evaluations) with a computational modeling approach using APSIM software. The model simulates plant responses to drought stress based on genetic parameters, eliminating the need for extensive physical trials while maintaining reliable drought tolerance assessment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs preliminary computational modeling and validation to establish accurate relationships between genetic parameters and drought responses before actual breeding evaluations. By pre-calibrating the APSIM model with existing data and validating it against field observations, the system prepares a ready-to-use predictive framework that accelerates subsequent breeding decisions without requiring time-consuming new trials.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If extensive field trials across multiple environments are conducted to account for genotype by environment interaction, then drought tolerance assessment becomes more accurate, but the complexity of the breeding program increases significantly

Engineering Contradiction:
Improvedrought tolerance measurementVSAvoidbreeding program complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent substitutes complex multi-environment field trial systems with a computational model (APSIM) that can simulate multiple environments and genotype responses simultaneously. The model incorporates environmental variables and genetic parameters to predict drought tolerance across diverse conditions, achieving high measurement precision without the logistical complexity of managing extensive physical trial networks.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The APSIM model serves multiple functions: it simulates different environmental conditions, predicts genotype responses to drought stress, evaluates genotype by environment interactions, and identifies tolerant genotypes all within a single integrated platform. This multi-functional approach replaces what would otherwise require separate trial programs for each assessment objective.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If drought stress is assessed using only flowering period stress index, then the assessment process is simplified, but the correlation with actual yield loss becomes non-significant

Engineering Contradiction:
Improvestress assessment simplicityVSAvoiddrought tolerance correlation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a dynamic, multi-stage stress assessment approach using the APSIM model that tracks drought stress effects throughout the entire plant growth cycle, not just during flowering. The model dynamically simulates water stress accumulation, plant response, and yield impact across different phenological stages, providing a comprehensive and reliable correlation between stress exposure and actual yield loss while maintaining operational efficiency through automated modeling.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3304377B1Method for determining drought tolerance in maize
Publication Date: 2020.01.15 LIMAGRAIN EURO SA
  • EP3304377B1 patent drawingFigure 1
  • EP3304377B1 patent drawingFigure 2
  • EP3304377B1 patent drawingFigure 3

AI summary

The present invention provides a method for determining the drought stress tolerance of a plant, said method comprising determining a stress index, measuring grain yield and drawing a linear regression between said stress index and grain yield on the basis of which drought tolerance is determined. Also provided herein are methods for comparing and ranking different plant lines based on their drought stress tolerance and identifying QTLs associated with drought stress tolerance.