Maize Ear Tip Expansion via Recessive Spo Determinants
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Solution Overview
Problem
Current maize breeding methods fail to effectively increase seed yield by manipulating the ear tip morphology using recessive genetic determinants, leading to limited commercial production of hybrids with expanded ear tips that contribute significantly to yield.
Innovation Solution
A method is developed to produce hybrid and inbred corn ears with expanded ear tips by selecting and combining recessive traits, known as 'spo' determinants, which enhance seed yield by increasing kernel number and size at the ear tip, using standard pure line inbred parents and self-pollination techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional dominant and additive gene actions are used to increase seed yield, then kernel weight and kernel number per ear improve, but the complexity of gene interactions increases making specific manipulation difficult
Solution Approach 1:
The patent extracts and isolates a specific recessive genetic determinant (ramosa allele) from the complex background of multiple gene interactions. By focusing on this single determinant that specifically controls ear tip morphology, the invention simplifies the genetic manipulation approach while achieving yield improvement through increased kernel number per ear without needing to manage complex polygenic interactions
Solution Approach 2:
The invention applies local quality by specifically modifying the ear tip region morphology through the ramosa allele without altering other parts of the plant or their beneficial traits. This localized genetic modification affects only the ear tip development, allowing increased kernel number in that specific region while maintaining heat tolerance, disease resistance, and fertilizer efficiency controlled by other genes
2Stability of the object's composition
If inbred lines are self-pollinated and selected for many generations to become homozygous, then uniform population and true breeding progeny are produced, but seed yield decreases due to inbreeding depression
Solution Approach 1:
The patent converts the harmful effect of inbreeding depression into a benefit by deliberately using self-pollination and selection to fix the recessive ramosa allele in homozygous state. The inbreeding process, which normally reduces yield, is used here to stabilize the desired ear tip morphology trait, and the resulting uniform population shows increased yield due to the specific genetic determinant being fixed
3Quantity of substance
If recessive traits are selected and combined to produce expanded ear tips, then kernel number per ear increases, but the trait expression requires specific breeding procedures and generation selection
Solution Approach 1:
The patent applies preliminary action by first identifying and selecting the ramosa allele in the F2 generation, then systematically advancing through F3, F4, and subsequent generations with specific selection criteria at each stage. This pre-planned multi-generational selection process efficiently fixes the recessive trait and produces uniform homozygous lines, minimizing the time required compared to traditional breeding methods that do not target specific determinants
Data Source
AI summary
This invention provides a novel means of making maize hybrids and inbreds with expanded ear tip phenotypes for promoting increased seed yield from recessive genetic determinants. This is achieved by making standard inbred×hybrid as well as inbred×inbred crosses followed by selection in the subsequent self-pollinated generations from these plants for expanded ear tip phenotype characteristics to produce new parent inbred lines. Next, the resulting inbreds, having a different pedigree but possessing the recessive expanded ear tip genetic determinants, are crossed to cause the expanded ear tip trait to express as a homozygous recessive trait in an otherwise primarily heterozygous hybrid.