Watermelon Sex Expression Breeding Using QTL Marker Selection

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Solution Overview

Problem

Current breeding methods for watermelon plants face challenges in identifying and utilizing alleles conferring beneficial traits due to difficulties in phenotypic assays, epistasis, and polygenic inheritance, which hampers the production of desired sex expression phenotypes in watermelon varieties.

Innovation Solution

The use of introgressed allele loci associated with specific genomic regions, such as those on linkage groups LG2, LG7, LG10, and LG11A, and linked markers for marker-assisted selection to introduce desired sex expression phenotypes, including percent male, female, and hermaphroditic flowers, into watermelon plants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional breeding methods are used to select watermelon plants based on phenotypic traits, then breeding efforts can produce watermelon lines with beneficial traits, but the process is hampered by difficulties in identifying alleles conferring beneficial traits due to lack of definitive phenotypic assays and issues such as epistasis and polygenic inheritance

Engineering Contradiction:
Improvephenotypic assay precisionVSAvoidbreeding efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces traditional phenotypic measurement methods with molecular genetic marker-based detection. Instead of relying on visual phenotypic assays that are subject to environmental influences and human error, the invention uses DNA markers to directly detect alleles associated with desired traits, providing objective and precise genetic information for selection decisions.

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

Solution Approach 2:

The patent introduces molecular genetic markers as intermediaries between the genotype and phenotype. These markers serve as detectable indicators that link directly to specific alleles or quantitative trait loci (QTL), allowing breeders to indirectly assess genetic composition without relying on complex phenotypic expression that may be influenced by epistasis or polygenic inheritance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If marker-assisted selection is implemented to identify alleles conferring beneficial traits, then the precision of trait identification improves, but the complexity of the breeding process increases due to the need for molecular tools and genetic analysis

Engineering Contradiction:
Improveallele detection precisionVSAvoidbreeding process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the complex trait selection process into discrete, manageable components by identifying and targeting specific molecular genetic markers or QTL regions. Instead of attempting to evaluate entire complex traits through phenotypic assays, the invention segments the problem into detecting individual marker alleles that can be analyzed independently using standardized molecular techniques.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If phenotypic assays are used to determine sex expression in watermelon plants, then selection for desired sex ratios can be performed, but the process becomes time-consuming and costly due to the need for extensive field observations and manual scoring

Engineering Contradiction:
Improvetrait selection easeVSAvoidbreeding cycle time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent performs genetic analysis at the molecular level during early plant development stages, before phenotypic expression becomes apparent. By detecting allele presence through marker analysis in seedling or juvenile plants, the invention enables selection decisions to be made early in the breeding cycle, eliminating the need to wait for plants to mature and express their phenotypic traits in the field.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3363284B1Methods and compositions for watermelon sex expression
Publication Date: 2026.04.08 SEMINIS VEGETABLE SEEDS INC
  • EP3363284B1 patent drawingFigure 1A~1C
  • EP3363284B1 patent drawingFigure 2(a)~2(d)
  • EP3363284B1 patent drawingFigure 3

AI summary

The present disclosure provides for unique watermelon plants with a desired sex expression phenotype and their progeny. Such plants may comprise an introgressed QTL associated with a desired sex expression phenotype. In certain aspects, compositions, including distinct polymorphic molecular markers, and methods for producing, breeding, identifying, selecting, and the like of plants or germplasm with a desired sex expression phenotype are provided.