Wheat fields under a thermal gradient, symbolizing growing degree days.

Decoding Wheat: How Sowing Dates Impact Growth and Yield

Nico Varela in Climate & Environment August 2025 • 4 min read.

"Unlock the secrets to optimizing your wheat crop by understanding the critical relationship between sowing dates, climate, and cultivar selection."

Wheat (Triticum aestivum L.) stands as a cornerstone of global nutrition, providing sustenance through bread, pasta, and more. Brazil, particularly its southern region, holds significant potential for wheat cultivation due to favorable soil and climate conditions.

However, achieving consistent yields requires a deep understanding of how environmental factors influence the crop's development. Unpredictable weather patterns, such as variations in rainfall and temperature, highlight the need for precise agricultural strategies.

This article delves into the critical relationship between sowing dates, climate, and the growth cycle of various wheat cultivars. By analyzing the growing degree-days sum and the duration from sowing to physiological maturity, we aim to provide insights that can help farmers optimize their wheat production.

The Science of Sowing: How Timing Affects Wheat Development

Wheat fields under a thermal gradient, symbolizing growing degree days.

A study conducted in Cascavel, Paraná, Brazil, from 2007 to 2011, examined thirteen wheat cultivars sown on three different dates: April 25th, May 15th, and May 25th. Researchers meticulously tracked the number of days from sowing to silking (flowering) and physiological maturity (when the grain is fully developed), as well as the growing degree-days sum for each period. The data also included grain yield and hectoliter weight (a measure of grain density).

Growing degree-days (GDD) are a measure of heat accumulation, directly related to the average daily air temperature. For wheat, the base temperature is 5°C. By calculating the GDD, it’s possible to predict how different sowing dates, and therefore different temperature exposures, affect crop development. The study used the following formula:

GD = ∑(Ti - Tb)
Where: Ti = Average daily temperature (°C)
Tb = Base temperature 5°C
n = Number of days in the period considered

The results revealed that the average time from sowing to silking was 71 days. The average length from silking to physiological maturity was 54 days. Later sowing dates (May 25th) led to an increase in the time from sowing to silking, likely due to decreased air temperatures. The average growing degree-days sum from sowing to physiological maturity was 1487.

Optimizing Wheat Production: Key Takeaways

The study highlights the importance of sowing date selection for wheat production. Sowing date significantly affects the duration of different growth stages and the accumulation of growing degree-days, which, in turn, influences yield and grain quality.

Cultivars like CD 114, CD 120, CD 121, CD 122, CD 124, and Onix stood out for their shorter silking to physiological maturity period and high productivity. These cultivars may be particularly well-suited for regions with specific temperature patterns.

By carefully considering the thermal requirements of different wheat cultivars and the climate of the growing region, farmers can make informed decisions about sowing dates to maximize yield and grain quality. This knowledge is especially crucial in the face of increasingly variable weather conditions.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.5897/ajar2013.7809, Alternate LINK

Title: Growing Degree-Day Sum And Crop Growth Cycle Duration For Wheat Cultivars At Different Sowing Dates

Subject: General Agricultural and Biological Sciences

Journal: African Journal of Agricultural Research

Publisher: Academic Journals

Authors: Maia Noreto Lorena, Yuji Tsutsumi Claudio, Carlos Torres Da Costa Antonio, De Assis Franco Francisco

Published: 2015-01-15

Everything You Need To Know

What is the significance of wheat in the context of global nutrition and specifically in Brazil?

Wheat is a vital crop, providing sustenance globally through items like bread and pasta. In Brazil, especially its southern region, the potential for wheat cultivation is considerable due to favorable conditions. Consistent yields depend on understanding how environmental factors influence wheat's development. Unpredictable weather, such as variations in rainfall and temperature, necessitates precise agricultural strategies.

How do sowing dates impact the different growth stages of wheat?

Sowing dates significantly affect the duration of different growth stages in wheat, specifically the time from sowing to silking (flowering) and from silking to physiological maturity (when the grain is fully developed). A study in Cascavel, Paraná, Brazil, examined how sowing dates of April 25th, May 15th, and May 25th, influenced the growth cycle of thirteen wheat cultivars. The analysis of growing degree-days sum and the length of these stages helps optimize wheat production.

What are growing degree-days (GDD) and how are they used in wheat farming?

Growing degree-days (GDD) are a measure of heat accumulation used to predict crop development. For wheat, the base temperature is 5°C. By calculating GDD, it’s possible to understand how different sowing dates, and thus different temperature exposures, affect crop development. The formula is GD = ∑(Ti - Tb), where Ti is the average daily temperature, Tb is the base temperature, and n is the number of days. The average GDD sum from sowing to physiological maturity was 1487 in the study.

What were the key findings of the study conducted in Cascavel, Paraná, Brazil, regarding sowing dates?

The research in Cascavel, Paraná, Brazil, from 2007 to 2011, examined thirteen wheat cultivars sown on three different dates: April 25th, May 15th, and May 25th. Researchers tracked the number of days from sowing to silking (flowering) and physiological maturity (when the grain is fully developed), as well as the growing degree-days sum for each period. The data also included grain yield and hectoliter weight (a measure of grain density). The results revealed that later sowing dates (May 25th) led to an increase in the time from sowing to silking, likely due to decreased air temperatures.

Why is it important to consider sowing dates when cultivating wheat?

The study emphasizes the importance of selecting the right sowing date for wheat production. The sowing date impacts the duration of growth stages and the accumulation of growing degree-days, which in turn influences the yield and quality of the grain. Understanding the relationship between these factors allows for optimizing agricultural practices to maximize wheat production in regions like Brazil.