Wheat Varieties – Winter and Spring Wheats. Specifications And Milling

Wheat is the source of most flour for a wide range of baked goods. A great deal of attention must be paid to choosing the right type of flour for any process and in many cases this starts with the wheat variety. We have at our disposal the following types:-

• bread flour
• biscuit flour
• cake flour
• treated and chlorinated cake flour for sponges and cakes which need a high ratio
• pie pastry flour especially for meats
• wholemeal flour
• brown flour
• gluten-free flour

Wheat Varieties

Most wheat is classified according to the time of planting. The main divisions are winter wheat and spring wheat. Winter wheat is planted in autumn whilst spring wheat is planted when ever conditions are favourable enough in the spring.

Winter wheat

Winter wheat is a vital crop grown in many parts of the world, prized for its adaptability, productivity, and role in producing essential products such as bread, pasta, and animal feed. Understanding winter wheat varieties and their cultivation is key to optimizing yield and ensuring sustainable production. There are four basic types and we will cover these off here.

Group 1: Established varieties used for bread making.

Group 2: More recent varieties with wheats of more limited bread-making p[otential

Group 3: soft varieties for biscuit, cakes and other types of flour

Group 4: Wheat varieties for specialist uses.

Winter Wheat Overview

Winter wheat (Triticum aestivum) is primarily planted in temperate regions where winters are cold but not too severe. Unlike spring wheat, which is sown and harvested in a single growing season, winter wheat is sown in the fall and lies dormant during the winter, allowing it to establish a strong root system before resuming growth in the spring. This extended growing period often results in higher yields than spring wheat.

Varieties of Winter Wheat

Winter wheat varieties are categorized based on several factors, including hardness (hard vs. soft), color (red vs. white), and end-use (bread, pasta, pastry, etc.). Each variety has specific traits that make it suitable for certain climates, soil types, and end uses.

1. Hard Red Winter Wheat (HRW):
   • Use: Bread and all-purpose flour
   • Protein Content: 10-13%
   • Regions: Grown primarily in the Great Plains of the U.S., it is known for its high protein content, making it ideal for yeast bread.
   • Characteristics: It is hardy, resilient to cold weather, and produces strong gluten, which is ideal for baking leavened bread.
2. Soft Red Winter Wheat (SRW):
   • Use: Pastries, crackers, cakes
   • Protein Content: 8-10%
   • Regions: Commonly grown in the eastern U.S. and southern Canada.
   • Characteristics: This variety has a lower protein content and is used for products that require a soft, delicate crumb, such as pastries and cakes. SRW is less tolerant of drought but thrives in moisture-rich soils.
3. Hard White Winter Wheat (HWW):
   • Use: Bread, tortillas, Asian noodles
   • Protein Content: 11-13%
   • Regions: Grown in the U.S. (primarily Kansas), Australia, and China.
   • Characteristics: Hard white wheat is similar to HRW but has a lighter color and milder flavor, making it desirable for products like white bread and tortillas. It offers high nutritional value and strong gluten formation.
4. Soft White Winter Wheat (SWW):
   • Use: Pastries, cakes, flatbreads
   • Protein Content: 8-10%
   • Regions: Primarily grown in the Pacific Northwest.
   • Characteristics: With a low protein content, SWW is used for products requiring tender, crumbly textures. It is well-suited for regions with mild winters and ample rainfall.
5. Durum Wheat:
   • Use: Pasta and semolina
   • Protein Content: 12-15%
   • Regions: While primarily a spring wheat, some varieties of durum are grown as winter wheat in milder climates like parts of southern Europe and North Africa.
   • Characteristics: Durum wheat has the hardest kernels and is used predominantly for pasta and couscous due to its high protein and gluten content.

When to Sow Winter Wheat

The timing of sowing winter wheat depends on the specific variety and the local climate. Generally, winter wheat is sown between late September and early November, with regional variations based on weather patterns and frost dates. The goal is to give the wheat enough time to establish roots before freezing temperatures set in.

• Temperate Regions (e.g., U.S. Midwest, Europe): Winter wheat is typically sown in late September to October.
• Colder Climates (e.g., Canada, northern Europe): In areas with harsher winters, winter wheat may be sown earlier in September to allow sufficient time for germination before frost.
• Warmer Climates (e.g., Mediterranean, southern U.S.): Sowing can occur as late as November, as the winters are milder and the risk of frost is lower.

The ideal planting depth is usually around 1.5 to 2 inches, ensuring the seeds are deep enough to access moisture but not so deep that they cannot sprout easily. Proper soil moisture is critical for germination, so growers often wait until after the first fall rains to sow.

How Winter Wheat Grows

Germination and Early Growth (Fall)

Once sown, winter wheat undergoes several developmental stages:

1. Germination: If moisture and temperature conditions are favorable (optimal soil temperature is around 54°F to 64°F or 12°C to 18°C), the seed will absorb water and germinate within 5 to 10 days.
2. Tillering: As the wheat develops, it enters the tillering phase, where the plant produces additional shoots called tillers. This phase occurs during the fall and is crucial for increasing the potential number of heads (and grains) per plant, influencing yield. Tillers are important because each one has the potential to produce a wheat head, contributing to the overall yield. During this stage, the crop’s nitrogen demand increases, and adequate nutrition (especially nitrogen fertilization) is critical. It is claimed to be a more important feature for spring wheats.
3. Dormancy: Once the temperature drops, the wheat plant enters dormancy, halting visible growth but continuing to develop its root system below the soil. This dormancy allows the plant to survive the winter cold.

Overwintering and Growth Resumption (Winter to Spring)

Winter wheat is particularly hardy, capable of surviving freezing temperatures due to its ability to undergo vernalization— a process where exposure to cold is necessary for the wheat to flower in the spring. Snow cover can protect the plants during the winter, insulating them from extreme cold and preventing frost damage.

As the soil warms in early spring, winter wheat resumes growth. The plant’s energy shifts from root development to producing leaves and stems.

Growth Phases (Spring)

1. Stem Elongation: As temperatures rise in the spring, the wheat stems elongate, and the plant produces nodes. This growth phase marks the wheat’s transition into reproductive development.
2. Jointing Stage: During this phase, the wheat begins forming its grain head, which will later develop into kernels. Adequate rainfall and nutrient availability are critical during this time to ensure high yields.
3. Boot Stage: As the plant matures, the grain heads become more defined. At the boot stage, the heads are still enclosed within the leaf sheath, resembling a boot, hence the name. This phase is important for determining the potential number of kernels per head.
4. Heading and Flowering: The grain heads eventually emerge from the leaf sheath, marking the heading stage. This is followed by flowering, which usually occurs within 3 to 5 days after heading. During flowering, the wheat is particularly sensitive to environmental stresses like drought or extreme temperatures, as they can reduce yield.

Grain Development and Ripening (Late Spring to Early Summer)

Once the wheat flowers, grain development begins. This period is divided into three phases:

1. Milk Stage: At first, the developing kernels are filled with a milky fluid, which hardens as the grain matures.
2. Dough Stage: As the wheat progresses toward maturity, the kernels enter the dough stage, where they become firmer but still malleable.
3. Ripening: The final phase is the ripening stage, where the kernels harden and turn golden brown. At this point, the wheat is ready for harvest.

Environmental and Soil Requirements

Winter wheat thrives in a range of soils but performs best in well-drained loams with a pH between 6.0 and 7.0. It is adaptable to different climates but requires cold temperatures during its vernalization period to trigger flowering. Temperature fluctuations during its growth stages can affect yield, with frost during the heading and flowering stages causing the most damage.

• Moisture: Winter wheat is moderately drought-tolerant, but consistent moisture during the germination and jointing stages is essential for proper development.
• Fertilization: Nitrogen is the key nutrient for winter wheat, influencing tillering, leaf growth, and kernel development. Split nitrogen applications (before planting and during the jointing phase) can help optimize uptake and reduce losses from leaching.

Pest and Disease Management

Winter wheat can be vulnerable to a range of pests and diseases, which can vary depending on the region and weather conditions. Common pests include aphids, Hessian flies, and armyworms, while diseases like powdery mildew, rust, and Fusarium head blight can impact yield and grain quality.

To manage these issues, growers often implement integrated pest management (IPM) strategies that include crop rotation, resistant wheat varieties, and judicious use of fungicides and pesticides.

Harvesting Winter Wheat

Winter wheat is typically harvested in the late spring or early summer, depending on the region. The ideal harvest time is when the grain has reached full maturity, which occurs when the kernels are dry and hard, and the wheat stalks have turned golden. At this point, moisture content in the grain should be around 13-15%, making it suitable for storage.

Harvesting is usually done with combines, which cut the wheat, thresh the grain from the heads, and separate the chaff.

Spring Wheat

Spring wheat is the other of the two main types of wheat cultivated globally, the other being winter wheat we have just discussed earlier. It is classified as “spring” wheat due to its sowing and growing season, typically occurring in the spring months, although the specific timing can vary depending on the region. This wheat is primarily grown in regions with harsh winters, where winter wheat cannot survive the cold. In this response, I will cover the characteristics of spring wheat varieties, its sowing and growing practices, key environmental factors, and the challenges associated with its cultivation. Much of what is stated here is similar to winter wheat but for the sake of completeness it is important to highlight similarities and then differences.

Characteristics of Spring Wheat Varieties

Spring wheat (Triticum aestivum) is prized for its high protein content, which makes it ideal for bread and pasta production. It is generally divided into two main types:

1. Hard Red Spring Wheat (HRSW): Known for its high gluten content, hard red spring wheat is widely used in bread making. It has a high protein content, typically ranging from 12% to 15%, making it perfect for products that require strong dough structures, such as artisan breads, pizza crusts, and bagels.
2. Soft White Spring Wheat (SWSW): This variety is softer and has lower protein levels (9%–11%), making it ideal for products that require a lighter, finer texture, such as cakes, pastries, and noodles.

In addition to these two main types, there are specialized varieties of spring wheat developed to meet specific agricultural or nutritional goals, such as:

• Drought-resistant varieties: Bred for regions with limited water availability.
• Disease-resistant varieties: Developed to combat common wheat diseases like rusts and blights.

Optimal Growing Conditions

The regions where spring wheat thrives typically have distinct seasons, with cold winters and moderately warm summers. Spring wheat prefers:

• Temperature: It requires warm temperatures for germination, ideally between 15°C and 24°C (59°F to 75°F).
• Soil: Spring wheat does best in well-drained soils with good water-holding capacity, including loamy and clay-loam soils, though it can adapt to a wide range of soil types as long as the soil pH is between 6.0 and 7.5.
• Rainfall: A moderate level of rainfall (300–600 mm annually) is ideal for spring wheat. It needs a consistent water supply during the growing period but cannot tolerate waterlogging.
• Sunlight: Like most cereals, spring wheat requires full sunlight, particularly during the reproductive stages, to ensure a good yield.

Sowing of Spring Wheat

Timing of Sowing

The timing of sowing spring wheat is crucial for optimizing yields. Unlike winter wheat, which is sown in the autumn and overwinters in a dormant state, spring wheat is planted after the winter frost danger has passed. The exact timing of sowing varies depending on regional climates:

• Northern Hemisphere: In temperate regions such as Canada, the northern United States, and parts of Europe and Russia, spring wheat is usually sown in early spring, from March to May.
• Southern Hemisphere: In regions like Argentina or Australia, where the seasons are reversed, it is typically sown from August to October.

The goal is to sow the wheat as soon as the soil is workable and has warmed up sufficiently for germination, while also ensuring that the crop avoids late-spring frosts that could damage young plants.

Seed Preparation

Seed selection is a key aspect of spring wheat cultivation. Certified seeds, free from disease and with high germination potential, should be used. Farmers often treat seeds with fungicides or other protective treatments to minimize the risk of seed-borne diseases like smut, bunt, or rust.

Sowing Methods

Spring wheat is generally planted using a drill seeding method, which ensures even distribution of seeds and proper seed-to-soil contact. This method offers several advantages:

1. Even distribution: It prevents overcrowding and ensures the plants have adequate space to grow.
2. Optimal depth: Seeds are planted at a consistent depth of about 2.5 to 4 cm (1–1.5 inches), which promotes uniform germination.

Another method sometimes used is broadcast seeding, where seeds are scattered across the field and then harrowed into the soil. While this method is faster, it can lead to uneven distribution and may reduce yields due to competition between plants.

Growth Stages of Spring Wheat

1. Germination and Emergence

Once the seeds are sown and temperatures rise above 10°C (50°F), germination begins. This stage typically takes 7–14 days, depending on soil moisture and temperature. The seed absorbs water, swells, and sprouts, with the first leaves emerging above the soil surface shortly thereafter.

2. Tillering

The effect of tillering for spring wheat is not that much different for winter wheat. After emergence, the plant enters the tillering stage, where it begins producing additional stems or tillers. 

3. Stem Elongation

Following tillering, the plant shifts its energy toward stem growth. This stage is characterized by the rapid elongation of the main stem, and the formation of nodes and internodes. Proper irrigation during this phase is essential, as water stress can reduce the plant’s ability to support multiple tillers and limit grain production.

4. Booting and Heading

As the plant approaches maturity, it enters the booting stage, where the wheat head develops within the uppermost leaf sheath (the boot). Eventually, the head emerges, signaling the heading stage. The optimal conditions at this point include sufficient moisture and sunlight to promote grain formation. During heading, the plant begins the reproductive process, and good pollination is essential for grain development.

5. Flowering and Grain Fill

After heading, flowering (also called anthesis) occurs. Spring wheat is self-pollinating, so the flowers pollinate themselves. The most critical period for yield formation is the grain-filling stage, where the wheat kernels develop and grow. Adequate water and nutrients are key to ensuring plump, healthy grains.

6. Ripening and Harvest

As the wheat matures, the plant turns golden brown, indicating that it is nearing harvest. The grain moisture content decreases, and the kernels harden. Harvest typically occurs when the grain moisture content is around 14%–16%. Timing the harvest is crucial: if done too early, the wheat may be too moist to store, but if delayed, the grain could shatter or be damaged by weather.

Fertilization and Nutrient Management

Spring wheat requires a balanced supply of nutrients to achieve optimal yields. Key nutrients include:

• Nitrogen (N): Essential for vegetative growth, nitrogen should be applied at various stages, with a major portion applied at planting and smaller doses during tillering and heading.
• Phosphorus (P): Important for root development and early growth, phosphorus should be applied at planting.
• Potassium (K): Necessary for overall plant health and disease resistance, potassium can be applied along with phosphorus.
• Micronutrients: Zinc, copper, and manganese may be required depending on soil conditions.

Soil testing before planting is critical to determine nutrient levels and guide fertilizer application. Over-fertilization, particularly with nitrogen, can lead to lodging (where the plant falls over), reducing yield.

Pests and Diseases

Spring wheat faces a variety of pest and disease challenges:

• Wheat rusts (stem, leaf, stripe): Fungal diseases that can significantly reduce yields if left unchecked. Resistant varieties and fungicides are common control measures.
• Powdery mildew: A fungal infection that appears as white powdery spots on leaves, reducing photosynthesis and grain fill.
• Insects: Pests like aphids, wheat stem sawfly, and armyworms can damage spring wheat. Integrated pest management (IPM) practices, such as crop rotation, biological control, and judicious pesticide use, help manage insect pressure.

Harvesting and Post-Harvest Practices

Spring wheat is typically harvested using a combine harvester, which cuts, threshes, and cleans the grain in a single operation. The timing of harvest is critical to avoid losses due to over-ripening, lodging, or adverse weather. After harvest, the wheat grain must be dried to a moisture content of around 12% for safe storage. Proper drying and storage conditions (cool, dry environments) are essential to prevent spoilage or pest infestations.

Challenges in Spring Wheat Cultivation

1. Climate variability: Unpredictable weather patterns, such as late frosts or drought, can affect the timing of sowing and the overall yield.
2. Water availability: In regions with limited rainfall, water management is crucial. Irrigation may be needed during critical growth stages, but excessive water can lead to root diseases and lower yields.
3. Soil health: Continuous wheat cultivation without proper rotation can lead to soil depletion and increased pest and disease pressures.

Winter and spring wheat varieties offer farmers a versatile crop with several end uses, from bread flour to pasta. Its cultivation follows a seasonal cycle that relies on specific environmental conditions and management practices, from careful sowing in the fall to harvesting in the summer. Understanding the intricacies of winter and spring wheat varieties and their growth patterns allows farmers to maximize yield and produce high-quality grain. The adaptability of both types of wheat to diverse climates and soils, along with its higher yield potential compared to spring wheat, makes it a cornerstone of global agriculture.