Theses and Dissertations

Advisor

Reed, Vaughn

Committee Member

Dhillon, Jagmandeep

Committee Member

Soignier, Tyler

Committee Member

Bumguardner, Amee

Committee Member

Bryant, Corey

Date of Degree

5-15-2026

Original embargo terms

Immediate Worldwide Access

Document Type

Graduate Thesis - Open Access

Major

Plant & Soil Sciences (Agronomy)

Degree Name

Master of Science (M.S.)

College

College of Agriculture and Life Sciences

Department

Department of Plant and Soil Sciences

Abstract

In Mississippi (MS), a 5.6 Mg ha-1 yield gap exists between the potential and actual corn (Zea mays L.) grain yield. The disparity underscores unrealized yielding potential of modern hybrids under current agronomic management practices. This study evaluated the yield response of four commercially grown top performing hybrids planted at five plant densities (6.2, 7.4, 8.6, 9.9, and 11.1 plants m-2) across four locations in MS over two years. Grain yield and kernel weight were subject to analysis of variance. The analysis was performed two ways: hybrid-level analysis (HA) using two hybrids common across all site-years, and location-level analysis (LA) conducted separately by location for Starkville, Stoneville, Raymond, and Verona, MS. Results from HA showed that the hybrid by location and main effect of plant density were significant for grain yield. Hybrid by location differences only existed due to yield differences observed at one location, where hybrid DeKalb 67-44 outperformed Revere 1627. Moreover, grain yield was maximized at 7.4 plants m-2 plant population as per HA. The LA analyses indicated a hybrid main effect in Starkville and Verona, and plant density main effect in Stoneville and Raymond. At Starkville, hybrid Revere 67-44 produced the highest yield (13.0 Mg ha-1). At Verona, hybrid Revere 1627 produced the highest yield (9.3 Mg ha-1), which was not significantly different from DeKalb 67-44 (8.7 Mg ha-1). Similar to HA analysis, plant density of 7.4 plants m-2 produced the highest yield at Stoneville and Raymond, reaching 10.5 and 13.2 Mg ha-1, respectively. The LA analyses indicated that kernel weight was influenced by hybrid by plant population, hybrid by year, and plant population by year interactions, in addition to a significant main effect of year. Overall, the yield differences among top performing hybrids were minimal, indicating that optimizing plant population may be more important than hybrid choice for maximizing yield under the conditions evaluated.

Sponsorship (Optional)

Mississippi Corn Promotion Board

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