To be successful in dual-purpose systems, wheat varieties often require traits sometimes overlooked in grain-only systems. These include fall forage yield potential, date of first hollow stem, recovery potential from grazing, resistance to viral diseases more commonly transmitted under early sowing, high temperature germination sensitivity, long coleoptile, and tolerance to low soil pH and aluminum toxicity.
A recently revised publication from the Department of Agronomy and K-State Research and Extension examines the fall forage yield, date of first hollow stem, plant height, and grain yield of current varieties in dual-purpose versus grain-only systems.
Fall forage yield potential 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 can be produced for every 1,000 pounds of wheat forage produced in an acre. Forage production is dependent on variety selection, planting date, seeding and nitrogen rates, and fall temperatures and precipitation.
Date of first hollow stem is an important trait in dual-purpose systems (Figure 1). Terminating grazing at the right time is essential to maintaining grain yield potential. Grazing past first hollow stem can decrease wheat grain yield by as much as 1 to 5 percent per day. Varieties with a shorter vernalization requirement might reach first hollow stem up to 30 days earlier than varieties with a longer vernalization requirement, depending on environmental conditions. An early occurrence of first hollow stem reduces the grazing window into early spring. Date of first hollow stem depends on temperature and day length in photoperiod-sensitive varieties.
Figure 1. Wheat plant reaching the first hollow stem stage of growth, characterized by approximately 1.5 cm (or roughly the diameter of a dime) of hollow stem underneath the developing grain head. Photo by Romulo Lollato, K-State Research and Extension.
Grain yield following grazing is another important variety-specific trait in dual-purpose systems. Varieties that rely mostly on fall-formed tillers to produce grain yield generally show a greater yield penalty from grazing than varieties with good spring tiller potential.
To evaluate the above traits in grain-only and dual-purpose systems in Kansas, thirty-six commonly grown winter wheat varieties 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 early sowing date, increased nitrogen rate, and higher seeding rate; while a third trial was sown to the same varieties under grain-only management.
Check out how varieties compared in fall forage production, date of first hollow stem, and grain yield under both dual-purpose or grain only management systems in the full publication, which can be found online at: https://www.bookstore.ksre.ksu.edu/pubs/MF3312.pdf.
Romulo Lollato, Extension Wheat and Forages Specialist