An updated publication is now available in the Wheat Rx series that examines the performance of several wheat varieties grown for use in a dual-purpose system (grazing and grain). To be successful in dual-purpose systems, wheat varieties require traits sometimes overlooked in grain-only systems. These include fall forage yield, date of first hollow stem, grazing recovery potential, resistance to viral diseases transmitted when the crop is planted early, no high-temperature germination sensitivity, long coleoptile, and greater tolerance to low soil pH and aluminum toxicity. This publication evaluates fall forage yield, date of first hollow stem, plant height, grain yield, and test weight of current varieties in a dual-purpose system versus a grain-only system.
This article summarizes the updated publication. The full publication, MF3312 Dual-Purpose Wheat Variety Performance, is available online at: https://bookstore.ksre.ksu.edu/pubs/MF3312.pdf. Wheat Rx is a partnership between Kansas Wheat and K-State Research and Extension to disseminate the latest research recommendations for high-yielding and high-quality wheat to Kansas wheat farmers.
Fall forage yield is an important trait in dual-purpose systems because it sets the potential beef production from wheat grazing in the fall, winter, and early spring. Approximately 100 pounds of beef per acre can be produced for every 1,000 pounds of wheat forage produced in an acre. Forage production depends on variety, planting date, seeding and nitrogen rates, fall temperature, and precipitation.
The date of the first hollow stem is also an important trait in dual-purpose systems because terminating grazing at the right time is essential to maintaining the grain yield potential for subsequent harvest. Grazing past the first hollow stem can decrease wheat grain yield by as much as 1 to 5% per day.
Depending on environmental conditions, varieties with a shorter vernalization requirement might reach first hollow stem 15 to 20 days earlier than varieties with a longer vernalization requirement. An earlier occurrence of first hollow stem reduces the grazing window into early spring. The date of first hollow stem is dependent on temperature and day length.
Grain yield following grazing is another variety-specific trait important in dual-purpose systems. Varieties that rely mostly on fall-formed tillers to produce grain yield generally show a greater yield penalty due to grazing than varieties with a good spring tiller potential.
Description of site and methods
Sixteen commonly grown winter wheat varieties, as well as pre-release lines, were sown in three neighboring trials in the South Central Experiment Field near Hutchinson, Kansas. Two trials were sown to simulate dual-purpose management, characterized by an early sowing date, increased nitrogen rate, and higher seeding rate, while a third trial was sown using the same varieties under grain-only management. The publication provides more information on the experiment methods and site characteristics.
Fall forage yield
Fall forage production of the varieties evaluated ranged from 871 to 1,969 pounds of dry matter per acre, averaging 1,457 pounds of dry matter per acre (Table 1). There were significant statistical differences among the varieties, with 11 varieties falling into the highest forage-yielding group (range within the highest yielding group: 1,370 to 1,969 pounds of dry matter per acre).
First hollow stem
The first hollow stem is reported in the day-of-year format. For reference, day of the year 80 is equivalent to March 21. Average occurrence of first hollow stem was day 76 (Table 1), ranging from day of year 72 for early varieties to day of year 83 for late varieties. These dates represent a normal release from winter dormancy; for reference, about 15 days before the dormancy release measured in 2022-23. The earliest varieties to reach first hollow stem were AP24 AX and AR Iron Eagle 22AX. The latest variety to achieve first hollow stem was KS Providence. All studied varieties reached first hollow stem within an 11-day interval. Previous reports of first hollow stem from Oklahoma have shown that early varieties may reach first hollow stem as much as 30 days earlier than later varieties, depending on environmental conditions. Kansas results may differ from Oklahoma results due to cooler winter temperatures holding crop development across varieties, and its interaction with photoperiod as day lengths were already long when temperatures were warm enough to allow for crop development.
Plant height
Varieties and cropping systems also differed significantly in plant height (Table 1). Plant height in the grain-only system averaged 24.9 inches, ranging from 23.6 to 26.9 inches. This average was null to 5.3 inches taller than the heights measured in the dual-purpose system (22.3 inches average height). The range in plant height was narrower in the grain-only system (3.2 inches) versus the dual-purpose system (4.8 inches), with varieties ranging from 19.4 to 25.9 inches.
Table 1. Fall dry matter forage yield, date of first hollow stem, and plant height under grain-only (GO) and dual-purpose (DP) systems in Hutchinson, KS, during the 2023-24 production year. Shaded values refer to the highest testing group. Values pertaining to the highest group are highlighted in bold.
Grain yield and grain test weight in grain-only or dual-purpose systems
The average grain yield in the grain-only trial was 53.5 bushels per acre, whereas the dual-purpose trial averaged 28.1 bushels per acre (Table 4 in the publication). Varieties that yielded statistically better than their counterparts in the grain-only trial were AP Sunbird and WB4347. The yield penalty from simulated grazing averaged 13.6 bushels per acre and ranged from 6.9 to 19.7 bushels per acre. Varieties included in the highest-yielding group of the dual-purpose trial were AR Iron Eagle 22AX, CP7017AX, Guardian, Golden Hawk, and WB4347. The weather conditions – characterized by enough moisture for forage production followed by drought conditions during the spring – likely worsened the effects of grazing since the larger crop likely used more water early in the season and had no moisture to recover later in the spring.
Test weight ranged from 55.1 to 62.7 pounds per bushel in the grain-only system and from 49.5 to 67.1 in the dual-purpose system (Table 4 in the publication). Guardian was the only variety with the highest test weight in both grain-only and dual-purpose systems. The experimental line AP Sunbird was in the highest test weight group under grain-only, and WB4347 was in the highest test group in the dual-purpose system.
Romulo Lollato, Extension Wheat and Forage Specialist
lollato@ksu.edu
Jane Lingenfelser, Assistant Agronomist
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