Evaluation of Publicly Available Maize Germplasm Adaptation to Environments in Nebraska

Authors

• Garrett Snodgrass, University of Nebraska-LincolnFollow

First Advisor

Blaine Johnson

Committee Members

Andrew Hopkins, Brian Rice, Reka Howard

Date of this Version

3-2026

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Agronomy

Under the supervision of Professor Blaine Johnson

Lincoln, Nebraska, March 2026

Comments

Copyright 2026, Garrett Snodgrass. Used by permission

Abstract

Publicly available maize germplasm represents an important resource for breeding programs seeking to expand genetic diversity and improve hybrid performance. However, effective use requires characterization of per se phenotypic performance of parental lines and evaluation of the parental line’s hybrid progeny adaptation to a given target population of environments. Furthermore, understanding population structure and heterotic grouping is imperative for maximizing efficiency of breeding decisions. The objectives of this study were to (1) evaluate phenotypic performance of parental lines and hybrids across environments in Nebraska, and to (2) refine heterotic group classification of parental lines within the University of Nebraska-Lincoln’s Hybrid Maize Breeding Project (HMBP). Genetic units (GUs) representing the HMBP’s germplasm collection were evaluated for per se performance at York, Nebraska in 2024, and a subsequent multi-environment trial (MET) was executed in 2025 on HMBP hybrids across five environments in Nebraska. Genomic and pedigree analysis clarified population structure of the HMBP germplasm collection and supported classification into heterotic groups. Together, findings provide a framework for utilizing publicly available maize germplasm for purposes of hybrid development and genetic improvement of the HMBP germplasm’s adaptation to environments in Nebraska. This project provides the foundation for future educational opportunities to students at the University of Nebraska–Lincoln.