Genetic diversity, developmental timing, and physiological efficiency for climate-resilient maize

Climate change threatens maize production globally, necessitating the development of resilient varieties adapted to environmental uncertainty. Assessing and utilizing genetic diversity is essential to enable crop adaptation. This dissertation examines genome-wide variation, developmental transitions, and physiological parameters in maize to identify genetic factors that control climate resilience traits. First, North American popcorn germplasm was genotyped to characterize genetic diversity and population structure critical for applying modern breeding techniques. Contrasting levels of diversity and inbreeding were observed between popcorn groups, with implications for heterosis. Genome-wide association identified novel nicosulfuron tolerance loci, demonstrating this panel’s utility for gene discovery. Next, diverse popcorn backgrounds introgressed with a null glossy15 allele exhibited modified timing of vegetative phase change and flowering, indirectly altering grain fill and drydown patterns. Complex interactions between developmental transitions, grain moisture, and quality traits highlight considerations for optimizing climate resilience. Finally, backcrossed inbred lines and mutants targeting quantitative trait loci were evaluated for impacts on carbon isotope discrimination, stomatal patterning, and gas exchange. Overlapping support implicates two intervals in mediating water dynamics through developmental and physiological mechanisms. Together, these objectives connect maize genomic diversity with validated gene effects and complex trait dissection to accelerate climate-resilient maize development. This research establishes resources to apply modern breeding techniques in popcorn, characterizes developmental and physiological genetic factors enabling adaptation, and identifies targets to optimize moisture dynamics and sustainable water use. Subsequent studies can build on these findings to drive rapid improvement of diverse maize germplasm.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Crop Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Sullivan, Madsen

Contributors dc:contributor

• Studer, Anthony J
• Juvik, John A
• Moose, Stephen P
• Williams, Martin M
• Thompson, Charles J

• Maize
• Climate Resilience
• Popcorn
• Genetic Diversity
• Population Structure
• Glossy15
• Drydown
• Water Use Efficiency
• Carbon Isotope Composition

Statement dc:rights

• Copyright 2024 Madsen Sullivan

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/124636

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F124636