Introduction

Fall forage production potential is one of the major considerations in deciding which variety to plant. Dual-purpose wheat producers, for example, may find varietal characteristics such as grain yield after grazing and disease resistance to be more important selection criteria than an advantage in early forage production potential. Forage-only producers might place more importance on planting an awnless wheat variety or one that germinates readily in hot soil conditions. Ultimately though, fall forage production is a selection criterion that should be considered. For more information on variety characteristics, please refer to OSU Fact Sheet PSS-2142 Wheat Variety Comparison Chart.

Fall forage production potential is determined by genetics, management and environmental factors. The purpose of this publication is to quantify some of the genetic differences in wheat forage production potential and grazing duration among the most popular varieties grown in Oklahoma. Management factors such as planting date, seeding rate and soil fertility are very influential and are sometimes more important than variety selection in determining forage production. Environmental factors such as rainfall amount and distribution and temperature also play a heavy role in dictating how much fall forage is produced. All of these factors along with yield potential after grazing and the individual producer’s preferences will determine which variety is best suited for a particular field.

Site Descriptions and Methods

The objective of the fall forage variety trials is to give producers an indication of the fall forage production ability of wheat varieties commonly grown throughout the state of Oklahoma. The forage trials were conducted under the umbrella of the Oklahoma State University Small Grains Variety Performance Tests. During the 2023-2024 crop year, the forage trials were conducted at the Chickasha and Stillwater test sites. Additionally, first hollow stem measurements were collected at both sites in 2024. Weather data for each location are provided in Figures 1 and 2.

A randomized complete block design with four replications was used at each site. Plots at each location were established in a conventionally tilled seedbed. At planting, 5 gal/acre of 10-34-0 was applied in seed furrow at Stillwater and Chickasha. The seeding rate at both locations was 120 lbs/acre. Forage was measured by hand clipping two, 1-m by 1-row samples approximately ½ inch above the soil surface from the interior rows within each plot. There was only one forage sampling date at each location. All samples were placed in a forced-air dryer after collection for approximately seven days and weighed. Fertility, planting date and clipping date information is provided in Table 1.

First hollow stem sampling began in early February at the Stillwater and Chickasha locations. It continued every three to four days on a by-variety basis until all varieties reached first hollow stem. Plant samples were collected for each variety by digging an approximately eight-inch section of row and selecting ten plants randomly from this sample. The largest tiller on each plant was split longitudinally, and the hollow stem below the developing grain head was measured. Varieties were considered to be at first hollow stem when the average measurement of the ten plant samples was 1.5 cm (5/8 inch) or greater. For more information on first hollow stem, refer to OSU Fact Sheet PSS-2147 First Hollow Stem: A Critical Wheat Growth Stage for Dual-Purpose Producers.

Figure 1. Average daily temperature (line graph) and rainfall (bar chart) from September 1, 2023 to April 1, 2024, at Stillwater, OK. Weather data courtesy Oklahoma Mesonet.

Figure 2. Average daily temperature (line graph) and rainfall (bar chart) from September 1, 2023 to April 1, 2024, at Chickasha, OK. Weather data courtesy Oklahoma Mesonet.

Results

As indicated in Figures 1 and 2, the 2023-2024 fall forage production season included moderate temperatures and low rainfall that was conducive to moderate fall forage production in our fields. Our results reflect these conditions in the sites evaluated. The average fall forage production at Stillwater was 2,915 lbs/acre, and values ranged from 1,452 to 4,433 lbs/acre (Table 2). Average forage production at Chickasha was 676 lbs/acre and values ranged from 377 to 1,220 lbs/acre (Table 3).

First hollow stem data are reported in ‘day of year’ (day) format for the winter wheat varieties in Table 4. To provide a reference, keep in mind that March 1 is day 60.The fall and winter months were characterized by moist conditions in Sillwater with temperatures somewhat normal. Adequate moisture resulted in timely wheat emergence, good plant development and slightly accelerated onset of first hollow stem for our region when considering the long-term average.The average winter wheat first hollow stem date at Stillwater was day 48 (February 17). This was 21 days earlier than 2023 (March 10), similar to 2022 (February 18), and 17 days earlier than the 20-year average (March 6). There was a 21-day difference between the earliest and latest varieties at Stillwater compared to a 14-day difference in 2023 and 32-day difference in 2022. The average winter wheat first hollow stem date for the Chickasha location was 58 (February 27). This was 13 days earlier than 2023 (March 12), 8 days later than 2022, and 7 days earlier than the 20-year average (March 6). There was a 13-day difference between the earliest and latest varieties at this location, compared to a 11-day difference in 2023 and 36-day difference in 2022.

Acknowledgments

The authors want to thank the Oklahoma Wheat Commission and the Oklahoma Wheat Research Foundation for providing partial funding for this research, as well as undergraduate. students Lettie Crabtree and Camila Bayer for their assistance with forage sampling collection and first hollow stem measurements. 

Seed Sources and Abbreviations

• AgriPro = AgriPro|Syngenta Seeds
• AGSECO = AGSECO Inc.
• KWA = Kansas Wheat Alliance
• LCS = Limagrain Cereal Seeds
• OGI = Oklahoma Genetics Inc.
• OSU = Oklahoma State University
• PlainsGold = PlainsGold Seeds
• WestBred = WestBred Wheat

Notes:
   STP: soil test P index;
   STK: soil test K index

Notes: Bolded values are not statistically different from the highest-yielding variety within a column.

Notes: Bolded values are not statistically different from the highest-yielding variety within a column.

NS: no statistical differences were detected among varieties within a column.