Maize MRCV Resistance Marker-Assisted Breeding

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Solution Overview

Problem

Current methods for controlling Mal de Rio Cuarto Virus (MRCV) in maize plants are ineffective, with limited commercially available hybrids showing strong resistance, and existing breeding techniques are slow and inaccurate for introducing MRCV resistance into elite corn hybrids.

Innovation Solution

A method using bi-parental QTL mapping to identify and select maize plants with decreased MRCV resistance by detecting specific alleles associated with marker loci on chromosomes 4 and 5, allowing for the introgression of resistance traits into new plants through marker-assisted breeding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional selective breeding methods are used to develop MRCV resistant maize lines, then resistance can be introduced into corn hybrids, but the process is slow and inaccurate with limited success in producing highly tolerant pedigrees

Engineering Contradiction:
ImproveMRCV resistanceVSAvoidbreeding time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces traditional mechanical selective breeding methods with molecular marker-assisted selection. Instead of relying on phenotypic observation and manual selection over multiple generations, the invention uses DNA markers (SSR, SNP, or other polymorphic markers) to directly identify and select plants carrying desired MRCV resistance alleles, dramatically accelerating the breeding process and improving accuracy.

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

Solution Approach 2:

The patent introduces molecular markers as intermediaries between the MRCV resistance trait and the selection process. These markers serve as genetic proxies that are closely linked to the resistance genes, allowing breeders to select for resistance without directly observing the trait or waiting for disease challenge, thus resolving the contradiction between reliability and time loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If Bt technology is widely adopted to control insect pests, then insecticide use decreases, but leaf hopper populations increase leading to amplified MRCV disease pressure

Engineering Contradiction:
Improveinsecticide useVSAvoidMRCV disease pressure
Core Design Contradiction:
Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The patent addresses the unintended consequence of Bt technology by developing MRCV resistant varieties that can withstand increased leaf hopper pressure. The resistance trait itself becomes the solution to the problem created by reduced insecticide use, converting the harmful increase in disease pressure into an opportunity to deploy genetically resistant cultivars.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the genetic parameters of maize varieties by introducing MRCV resistance alleles through marker-assisted selection. This genetic modification allows the crop to tolerate or resist the virus under conditions where leaf hopper populations are high, effectively adapting the crop to the new pest pressure regime created by widespread Bt adoption.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If marker loci are used to identify MRCV resistance alleles, then selection accuracy increases, but the complexity of genetic analysis and marker detection increases

Engineering Contradiction:
Improveresistance detection accuracyVSAvoidgenetic analysis complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the complex genome into manageable units by focusing on specific molecular markers (SSR, SNP, or other polymorphic markers) that are closely linked to MRCV resistance genes. Instead of analyzing the entire genome or relying on complex phenotypic assays, the invention breaks down the selection process into discrete marker-based steps, improving accuracy while controlling complexity through targeted analysis.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS10066271B2Genetic loci associated with Mal de Rio Cuarto virus in maize
Publication Date: 2018.09.04 AGRIGENETICS INC

AI summary

This invention relates to methods for identifying maize plants that having decreased MRCV. The methods use molecular markers to identify and to select plants with decreased MRCV or to identify and deselect plants with decreased MRCV. Maize plants generated by the methods of the invention are also a feature of the invention.