Planting date and seeding rate effects on soft red winter wheat

Authors: MUDIYANSELAGE, PRABATH - The Ohio State University; Baik, Byung-Kee; LINDSEY, LAURA - The Ohio State University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2025
Publication Date: 6/16/2025
Citation: Mudiyanselage, P.S., Baik, B.V., Lindsey, L.E. 2025. Planting date and seeding rate effects on soft red winter wheat. Agronomy Journal. 117(3). Article e70099. https://doi.org/10.1002/plr2.20419.
DOI: https://doi.org/10.1002/agj2.70099

Interpretive Summary: Wheat planting date critically influences disease and insect pest management, grain yield, and seed composition. There is a recommended planting date for soft red winter wheat, but farmers often have to plant later due to frequent rainfall and the late maturation of soybeans, which are the preceding crops in the double-cropping system. To offset possible yield loss due to delayed planting, farmers tend to increase their seeding rate. The existing wheat seeding rate recommendation needs to be updated based on planting date, especially considering modern cultivars and production techniques under current environmental conditions. Our study found that delayed planting resulted in smaller yield penalties than previously thought, particularly under mild winters and favorable conditions for kernel development and grain fill during late spring and early summer. The agronomic optimal seeding rate for early and timely planted wheat was determined to be 2.69 million seeds per hectare. For wheat planted approximately four weeks after the fly-free date or later, the agronomic optimal seeding rates were 3.12 and 4.39 million seeds per hectare, respectively. These findings provide wheat growers with a guideline for selecting a seeding rate that maximizes crop yield for early or timely planting and minimizes yield loss when planting is delayed due to frequent rainfall and late maturation of the preceding soybean crop.

Technical Abstract: In Ohio, it is recommended to plant soft red winter wheat [Triticum aestivum (L.)] within 10-days following the county’s Hessian fly (Mayetiola destructor)-free date to achieve maximum yields. However, due to wet weather in the fall and late maturing soybean [Glycine max (L.) Merr.] varieties, wheat is often planted after the optimum time. To mitigate yield losses due to late planting, a higher seeding rate may be necessary. Objectives of this research were to a) assess the main and interaction effects of planting date and seeding rate on soft red winter wheat grain yield, and (b) to determine the agronomic and economic optimum seeding rates (AOSR and EOSR, respectively) of wheat based on the planting date. An experiment was established during two growing seasons at two locations in Ohio with five wheat planting date and five seeding rate treatments ranging from 1.24 to 6.18 million seeds ha-1. Average AOSR for early and timely planted wheat was 2.69 million seeds ha-1. For wheat planted approximately four weeks of the fly-free date and beyond that time frame, average AOSRs were 3.12 and 4.39 million seeds ha-1, respectively. The EOSRs for the same three-time frames were 2.10, 3.00, and 4.37 million seeds ha-1, respectively. Results also indicated a lower yield penalty for late-planted wheat in Ohio than previously observed, which may be due to mild winters and the favorable conditions for kernel development and grain fill during late spring and early summer.