what causes low test weight in wheat



Test weight is an essential quality parameter in wheat production. It refers to the weight of a given volume of wheat and is used as an indicator of grain quality. Low test weight in wheat affects its marketability and can result in economic losses for farmers. There are several factors that can contribute to low test weight in wheat. Understanding these factors is crucial for farmers and agronomists in order to optimize wheat production and maximize yields. In this article, we will explore the various causes of low test weight in wheat and discuss potential solutions to overcome this issue.

Environmental Factors

Environmental conditions play a significant role in determining the test weight of wheat. Under adverse weather conditions, such as drought or extreme temperatures, wheat plants may experience physiological stress, leading to lower test weight. Water stress during the grain filling period is particularly detrimental to wheat yield and test weight. Insufficient moisture availability can reduce the development and filling of wheat kernels, resulting in lower test weight. High temperatures during grain filling can also negatively impact test weight by hastening grain maturation and reducing the duration of the grain filling period.

Furthermore, excessive rainfall or prolonged periods of high humidity can promote the growth of fungal pathogens, such as Fusarium spp. and Aspergillus spp., which can cause kernel damage and reduce test weight. These pathogens produce mycotoxins, which not only decrease test weight but also pose a risk to human and animal health. Another environmental factor to consider is soil fertility. Nutrient deficiencies or imbalances, such as nitrogen or potassium deficiencies, can affect wheat development and reduce test weight.

Cultural Practices

Cultural practices can significantly influence the test weight of wheat. Planting density is one of the crucial factors. When wheat is sown at high plant populations, competition for resources like nutrients, sunlight, and water intensifies, resulting in smaller and lighter kernels. On the other hand, low plant populations can lead to excessive tillering, which may result in poor kernel development and lower test weight.

The timing of planting is another cultural practice that can impact test weight. Late planting can expose wheat to adverse environmental conditions during critical growth stages, reducing grain filling and ultimately lowering test weight. Additionally, improper crop rotation, especially continuous wheat cultivation, can lead to the build-up of pests and diseases that affect grain quality and test weight. Therefore, practicing crop rotation with non-host crops can help mitigate such issues.

Genetic Factors and Varietal Selection

Genetic factors also play a crucial role in determining test weight in wheat. Different wheat varieties exhibit varying levels of resistance to environmental stress and pathogens, which can affect their test weight. Selecting high-quality and adapted varieties that are known to have good test weight can help farmers overcome low test weight issues.

Breeding programs have been successful in developing varieties with improved test weights. Genetic traits associated with test weight, such as grain size, kernel density, and kernel shape, are key considerations in varietal improvement. Breeding for disease resistance and tolerance to environmental stresses can also indirectly contribute to higher test weight. Farmers should consult local agricultural extension offices or seed companies to choose varieties that perform well under their specific growing conditions.

Pest and Disease Pressure

Insects, weeds, and diseases can have a detrimental impact on wheat test weight. Insect pests, such as Hessian fly and aphids, can infest wheat plants and cause direct damage, resulting in lower test weight. Weeds compete with wheat for resources and can reduce grain filling, ultimately affecting test weight. Proper weed management practices, including timely herbicide application and crop rotation, can mitigate these issues.

Diseases, such as rusts, powdery mildew, and Fusarium head blight, can significantly impact wheat yield and test weight. Fusarium head blight, caused by Fusarium spp., not only reduces test weight but also leads to the accumulation of mycotoxins, such as deoxynivalenol (DON), in the grains. To manage these diseases, farmers should consider planting resistant varieties, implementing crop rotation, and applying fungicides, if necessary.

Harvesting and Post-Harvest Factors

Improper harvesting techniques and post-harvest conditions can also contribute to low test weight in wheat. Harvesting wheat either too early or too late can result in low test weight due to incomplete grain filling or shattering, respectively. It is crucial to harvest wheat when it has reached physiological maturity to ensure optimal test weight.

Post-harvest factors, such as storage conditions and transportation, can also influence test weight. Improper storage conditions, such as high humidity or inadequate aeration, can lead to spoilage and the growth of molds, which can impact test weight. Similarly, rough handling during transportation can cause kernel damage and decrease test weight.


Low test weight in wheat can be attributed to various factors, including environmental conditions, cultural practices, genetic traits, pest and disease pressure, and harvesting and post-harvest factors. Understanding these factors and their interactions is crucial for farmers and agronomists to make informed decisions and implement appropriate measures to improve test weight. By selecting suitable varieties, optimizing planting density and timing, managing pests and diseases, and adopting proper harvesting and post-harvest practices, farmers can overcome low test weight issues and ensure optimal wheat production. Ultimately, a holistic and integrated approach is necessary to tackle this challenge and improve the overall quality and marketability of wheat crops.


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