Graduate Studies
Embargoed Master's Theses
First Advisor
Cody F. Creech
Second Advisor
Amanda C. Easterly
Committee Members
Katherine A. Frels, Ismail Dweikat
Date of this Version
5-2025
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 Professors Cody F. Creech and Amanda C. Easterly
Lincoln, Nebraska, May 2025
Abstract
Crop productivity in the semi-arid High Plains of the United States is primarily limited based on the low and unpredictable precipitation that the region receives. While winter wheat is the central crop in most rotations, growers are continually looking to diversify and intensify their cropping system rotations for both economic and system sustainability reasons.
Winter barley has gained farmer and stakeholder interest in recent years in the region. As a good option to be used as feed to livestock, having good drought tolerance and low fertility requirements, the crop is a great option for growers. Also, as a winter crop with many similarities to winter wheat, winter barley could be easily introduced to the system, with few logistical or equipment changes needed for integration. One of the challenges is the lack of recent, regional information regarding best performing genotypes, management, and fertilizer requirements. This work reports a series of experiments performed in Cheyenne and Banner Counties from 2021 to 2024 evaluating commercial and experimental genotypes, different seeding rates and different fertility strategies. The results indicate that the best performance varieties are P-954 and advanced breeding lines from the UNL Small Grains Breeding Program. Minimum seeding rate required to achieve optimum yields is 2.47 million seeds ha⁻¹. Winter barley’s yielding components are highly benefited by phosphorus fertilization, especially when combined with spring nitrogen top-dress.
Grain sorghum is known for its drought and heat tolerance and can be used as a livestock feed with nutritional value close to maize (Zea mays). The crop suffers from yield reductions from early fall frosts, decreasing the season’s length. Breeding efforts on early-season chilling tolerance can increase the viability of shifting to an earlier planting date, thus increasing the growing season, and protecting yield. This work studied 38 commercial and experimental genotypes with various levels of early-season chilling tolerance in split-plot trials with two planting dates. The trials were performed in 2023 and 2024 in Sidney, Nebraska. Results identified commercial genotypes that maintained performance under chilling conditions and experimental material that can be selected and used for breeding improvements towards both early-season chilling and drought tolerance.
Advisors: Cody F. Creech and Amanda C. Easterly
Comments
Copyright 2025, Rafael Marino Bley Cottica. Used by permission