Hybrid Maize 33Y74 Breeding via Genetic Male Sterility
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Solution Overview
Problem
Current maize breeding methods face challenges in efficiently producing hybrid maize with high grain yield, good dry down, and resistance to diseases and pests, while maintaining genetic uniformity and vigor, often relying on labor-intensive male sterility systems and limited by the need for precise control of male fertility.
Innovation Solution
The development of hybrid maize plant 33Y74, produced by crossing proprietary Pioneer Hi-Bred International inbred lines GE760321 and GE3260835, which combines high grain yield with good dry down and resistance traits, utilizing advanced breeding techniques such as backcross conversion and molecular marker-enhanced selection to introduce desired traits and ensure genetic stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional male sterility systems are used to control male fertility in maize breeding, then hybrid seed production is enabled, but the process becomes labor-intensive and complex
Solution Approach 1:
The patent extracts the male sterility function from complex manual or mechanical systems and integrates it into a simplified genetic control mechanism. By using a recessive sterile allele (st) in combination with a restorer allele (Rf), the system automatically determines male fertility without requiring external intervention, thus reducing breeding system complexity while maintaining reliable control.
Solution Approach 2:
The maize plants themselves determine their own male fertility status through their genetic composition. The interaction between the sterile allele (st) and restorer allele (Rf) creates a self-regulating system where plants with the stst genotype are male sterile and those with Rfst or RfRf are fertile, eliminating the need for external male sterility systems.
2Stability of the object's composition
If inbred lines are self-pollinated for multiple generations to achieve homozygosity, then genetic uniformity is improved, but vigor decreases
Solution Approach 1:
Instead of continuing to self-pollinate inbred lines to increase homozygosity (which would further reduce vigor), the patent inverts the approach by creating hybrids from two different inbred lines. This hybridization process restores vigor through heterosis while maintaining the genetic uniformity achieved during the inbreeding phase, effectively reversing the negative effect of prolonged self-pollination.
3Strength
If cross-pollination is used to produce hybrid progeny, then vigor is restored, but genetic uniformity is reduced
Solution Approach 1:
The patent applies local quality by maintaining different genetic characteristics in different parts of the breeding system. The inbred parent lines remain highly uniform and homozygous, while the hybrid progeny exhibit restored vigor through heterosis. This allows the system to simultaneously achieve both genetic uniformity in the parents and vigor in the hybrids, as each component serves its specific function.
Data Source
AI summary
A novel hybrid maize variety designated 33Y74 and seed, plants and plant parts thereof, produced by crossing Pioneer Hi-Bred International, Inc. proprietary inbred maize lines. Methods for producing a maize plant that comprises crossing hybrid maize variety 33Y74 with another maize plant. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into 33Y74 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. This invention relates to the hybrid seed 33Y74, the hybrid plant produced from the seed, and variants, mutants, and trivial modifications of hybrid 33Y74. This invention further relates to methods for producing maize lines derived from hybrid maize variety 33Y74 and to the maize lines derived by the use of those methods.