2025 Corn Grain Hybrid Testing Report

2025 Corn Grain Variety Testing Report

Prepared by Dayton Spackman, Cassidy Bumbaugh, and Daniela Carrijo
The Pennsylvania State University, Department of Plant Science

This report summarizes the performance of corn hybrids in Pennsylvania in 2025. Early-season hybrids (90-100 days relative maturity, i.e., zone 1) were evaluated in Lycoming and Centre Counties, mid-season hybrids (100-105 days relative maturity, i.e., zone 2) in Lycoming and Centre Counties, and late-season hybrids (105-118 days relative maturity, i.e., zone 3-4) in York, Lancaster, and West Chester Counties. Results are summarized by individual location (single trial) and by climatic zone, which combines data from multiple trials within each zone. We recommend using data summaries by climatic zone. We do not recommend using data from a single trial to make hybrid selection choices, even if the trial was conducted close to your farm. Individual location data summaries are only provided to support the zonal data summaries. The first step when using this report is to select the zone that best represents your operation, based on the location and hybrid relative maturity practiced in your farm.

All trials were laid out in small plots (4 rows spaced 30 inches apart and 20 feet long) in a randomized complete block design with four replications. Production details are described below for each trial. Plant population was determined early in the season. Each plot had approximately 34,000 plants per acre at post-emergence. Yield was determined by harvesting the center two rows with a research combine. Harvest moisture refers to the grain moisture at harvest, determined by a near-infrared spectroscopy system housed in the combine. Harvest moisture can be used to compare the maturity of hybrids of similar relative maturity. For example, comparing two 110-day hybrids, the one with higher harvest moisture likely has a longer maturity (requires more days from planting to harvest maturity). Lodging was determined by visual percentage immediately before harvest. All measurements were taken on all four replications and Analysis of Variance (ANOVA) was conducted within each trial for individual location data summaries and within each climatic zone for the zonal data summaries. The Least Significant Difference (LSD) by Fisher’s Test was calculated when ANOVA results indicated a significant difference between hybrids.

Using the LSD Value

The Least Significant Difference (L.S.D.) value is derived from a statistical test and can be used to compare varieties within each data summary. If the difference between any two varieties exceeds the L.S.D. value, they are considered "significantly different." The L.S.D. value is expressed in the same units as the measurement in question. For example, if within a given climatic zone, Variety #1 yielded 200 bushels/acre, Variety #2 yielded 180 bushels/acre, and the L.S.D. value is 10 bushels/acre, then Variety #1 yielded significantly higher than Variety #2 in that zone. The L.S.D. value can also be used to identify the "top yielding group". For example, if the highest yielding variety produced 200 bushels/acre and the L.S.D. value is 50 bushels/acre, then all varieties that yielded 150 bushels/acre or more are not significantly different than the highest yielding variety and can be considered the "top yielding group". The L.S.D. values can be calculated at different significance levels. Higher levels allow for better separation between varieties (lower L.S.D. values) at the cost of committing the error of separating varieties that are not truly different. Lower levels allow less separation between varieties (higher L.S.D. values) at the cost of overlooking true differences. In this report, L.S.D. values are given at the significance levels of 0.1 and 0.2. Based on the strong arguments of Carmer (1976)¹ specific to using L.S.D. values in variety performance tests, we generally recommend the 0.2 significance level when interpreting results in this report.

¹ Carmer, S.G. "Optimal Significance Levels for Application of the Least Significant Difference in Crop Performance Trials."  Crop Science 16:95-99, 1976.

Data Summary Zone 1

Data Summary Zone 2

Data Summary Zone 3-4

Production Details Zone 1 and 2

Weather Summary Zone 1 and 2

Production Details Zone 3/4

Weather Summary Zone 3/4