Marker-Assisted Brachytic Corn Breeding for Yield and Lodging
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Solution Overview
Problem
Existing corn breeding methods have not effectively utilized brachytic mutants due to severe yield reduction and lack of commercially relevant alleles, necessitating the identification of novel brachytic alleles and development of polymorphic markers for enhancing plant productivity and stability.
Innovation Solution
Methods for detecting and introgressing brachytic alleles in corn plants using polymorphic markers associated with specific genomic sequences, such as SEQ ID Nos: 1-22 and 86-109, to create hybrid, dwarf, or semi-dwarf corn plants with improved mechanical stability and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional corn breeding methods are used to increase crop yield, then grain yield increases, but plant height increases making plants more susceptible to lodging
Solution Approach 1:
The patent applies parameter changes by modifying the Br2 gene to create brachytic alleles that specifically alter plant height parameters while maintaining other agronomic parameters. The br2-10 allele, for example, reduces plant height by approximately 10-15 inches compared to wild-type, while preserving kernel yield and other organ sizes. This selective parameter modification resolves the contradiction between increasing yield (which typically requires taller plants) and maintaining lodging resistance (which requires shorter plants).
Solution Approach 2:
The patent employs local quality by creating alleles with localized effects on specific plant parameters rather than global changes. The brachytic mutations specifically target internode length and plant height while leaving car size, leaf area, and tassel structure relatively unchanged. This localized modification allows the plant to achieve the desired short stature for lodging resistance without compromising the reproductive organs needed for high yield.
2Reliability
If existing brachytic mutants are used to reduce plant height, then plant height decreases improving lodging resistance, but grain yield severely decreases
Solution Approach 1:
The patent resolves this contradiction through precise parameter changes in the Br2 gene sequence. By creating specific alleles like br2-10, br2-11, and br2-12 with controlled levels of functionality, the invention achieves moderate height reduction (10-20 inches shorter than wild-type) while maintaining grain yield at or above wild-type levels. This is in contrast to severe brachytic mutants that reduce height but also severely impact yield.
Solution Approach 2:
The patent applies partial action by creating alleles with intermediate functionality rather than complete loss-of-function mutations. The br2-10 allele, for example, retains partial Br2 protein functionality while still producing the desired brachytic phenotype. This partial modification is sufficient to reduce plant height for lodging resistance but not so severe as to compromise grain yield, thereby resolving the contradiction between these two parameters.
3Reliability
If brachytic alleles are introgressed into elite corn lines, then mechanical stability improves, but the complexity of breeding programs increases
Solution Approach 1:
The patent uses molecular markers as intermediaries to simplify the breeding process. Specific markers (e.g., umc10a-058, umc10a-138, umc10a-140) are tightly linked to the Br2 locus and serve as proxies for selecting plants carrying desired brachytic alleles. This marker-mediated selection acts as an intermediary that eliminates the need for complex phenotypic evaluation, allowing breeders to efficiently select for mechanical stability through simple DNA-based assays.
Solution Approach 2:
The patent replaces mechanical/phenotypic selection methods with molecular detection methods. Instead of manually measuring plant height and assessing mechanical stability in the field, the invention uses DNA-based marker detection to identify plants carrying brachytic alleles. This substitution of mechanical evaluation with molecular analysis significantly reduces breeding program complexity while maintaining accuracy in selecting for mechanical stability.
Data Source
AI summary
The present disclosure is in the field of plant breeding. The disclosure provides methods for breeding corn plants having a brachytic trait using marker-assisted selection. The disclosure further provides brachytic germplasm, markers associated with a brachytic trait for introgressing the trait into elite germplasm in a breeding program. This disclosure also provides brachytic or dwarf elite corn varieties having yield equal to or higher than conventional non-brachytic corn varieties.