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 varieties in a dual-purpose system versus a grain-only system.
This article summarizes information from the 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 is dependent on variety, planting date, seeding and nitrogen rates, and fall temperature and precipitation.
Date of first hollow stem is also an important trait in dual-purpose systems because terminating grazing at the right time is essential to maintain the grain yield potential for subsequent harvest. Grazing past 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 of importance 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
Twenty-one 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. More information on the experiment methods and site characteristics can be found in the publication.
Fall forage yield
Fall forage production of the varieties evaluated ranged from 213 to 679 pounds of dry matter per acre, averaging 354 pounds of dry matter per acre (Table 3). There were significant statistical differences among the varieties, with the highest forage producers being Guardian and KS Ahearn (489 – 679 pounds of dry matter per acre), followed closely by AP Prolific, LCS Atomic AX, and LCS Galloway AX (about 450 pounds of dry matter per acre).
First hollow stem
First hollow stem is reported in day-of-year format (for example, day of year 80 is March 21). The average occurrence of first hollow stem was day 91 (see Table 3 in the publication), ranging from day of year 85 for early varieties to day of year 92 for late varieties. These dates represent a fairly late release from winter dormancy, which was due to prolonged cold temperatures and dry winter conditions. The earliest varieties to reach first hollow stem were LCS Atomic AX and KS Hatchett. The latest variety to achieve first hollow stem was Whistler. All varieties reached first hollow stem within a 7-day interval. 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 the interaction with photoperiod.
Varieties and cropping systems also differed significantly in plant height (see Table 3 in publication). Plant height in the grain-only system averaged 22.9 inches, ranging from 19.2 to 28.0 inches. This average was only an inch taller than the average of all varieties in the dual-purpose system (21.9 inches). The range in plant height was narrower in the dual-purpose system, with varieties ranging from 19.4 to 25.9 inches. The tallest variety was Whistler at both management systems.
Grain yield and grain test weight in grain-only or dual-purpose systems
The average grain yield in the grain-only trial was 51.0 bushels per acre, whereas the dual-purpose trial averaged 48.9 bushels per acre (see Table 4 in publication). The weather conditions — characterized by severe drought across the season with cool and moist conditions after May 15 – were beneficial to late-maturing varieties across both systems. Varieties that yielded statistically better than counterparts in the grain-only trial were LCS Steel AX and Whistler. The yield penalty from simulated grazing averaged 2.1 bushels per acre and ranged from a positive gain of 3.6 bushels per acre to a loss of 7.5 bushels per acre. Varieties included in the highest-yielding group of the dual-purpose trial were CP7869, LCS Steel AX, and Whistler.
The only variety with the highest test weight at both grain-only (average: 60.8 pounds per bushel) and dual-purpose (average: 60.8 pounds per bushel) systems was Guardian, whereas the varieties CP7050 AX, CP7869, and LCS Atomic AX were in the highest test weight group under dual-purpose (see Table 4 in publication).
Romulo Lollato, Extension Wheat and Forage Specialist
Jane Lingenfelser, Assistant Agronomist