Introduction to Wheat Seed Germination Process
Wheat is a widely adapted crop and is grown from temperate, irrigated to hot , high-rain, and moist, humid to dry , cold environments. Seed germination is a factor which contributes Wheat crop yield. Temperature is considered an important issue for Wheat germination among the abiotic factors, since it convinces the water rate and additional substrates needed for growth and development. Wheat’s life cycle is the same for all animals, but it can occur at different times. Wheat is one of the most commonly consumed grains of cereals in the world. Wheat comes from a grass variety which is cultivated in countless varieties around the world.The primary breeding species is bread wheat. Many other species closely related to each other include durum, emmer, einkorn, and Khorasan wheat.
The Guide to Wheat Seed Germination
Wheat holds the prime position of all the world’s food crops. In India, wheat is the second major food crop next to rice and contributes approximately 25% to the country’s total food grain production. Over the last few years it has played a very important role in stabilizing the country’s food grain production.
Soil Requirements for Wheat Cultivation
Wheat is produced in a variety of soils. Soils with a texture of clay loam or loam, good structure and a moderate capacity to hold water are ideal for. Care must be taken to avoid soils that are very porous and too drained. The soil must react neutrally. Under dry conditions, heavy soil with good drainage is suitable for Wheat cultivation. Such soils absorb rainwater and then hold it well. However, heavy soils with poor structure and poor drainage are not appropriate as Wheat is susceptible to waterlogging. Wheat can be effectively grown on lighter soils, provided the capacity to retain water and nutrients is increased.
Seed Size and Rate for Wheat Seed Germination
Seed size is a very important parameter that influences nursery seedlings’ germination , growth, and biomass and that trend leads to future crop. Sowing of a species ‘mixed seed can result in a non-uniform density of seedlings, which can lead to variability in the seedlings’ vigor and size. In many tree species, the seed size controls germination and initial growth of the seedlings. Germination can rely on the seed ‘s ability to use reserves more efficiently, by mobilizing seed reserves to germinate seed traits. A common practice for regulating seed germination and subsequent seedling growth is grading based on their size and weight.
Under irrigated, timely sown conditions a seed rate of about 100 kg/ha at 38 g/1000 seeds is required. Seed rate must be increased to 125 kg / ha for late sown and rainfed conditions. Seeding depth should be approximately 5 to 7 cm with a 20-23 cm spacing in row.
Factors Affecting Wheat Seed Germination
Germination in a Wheat seed starts after a short period of dormancy. Wheat’s have a low dormancy level, which is easily broken down , allowing germination to begin. Some varieties of Wheat have a dormancy derived from their seed coat, which lasts 3 to 7 months. This dormancy is then correlated with anthocyanins, the enzymes that give the red color to the seed coat.
Moisture from the soil affects seed germination speed. If the soil is warm, germination of seeds is fast. The speed of seed germination slows as the soil dries to near the permanent wilting point. Seed germination can take 10 days at 7 ° C when the soil hits the permanent wilting stage, instead of 5 days at 7 ° C when there is enough moisture. The seed germination process will stop and begin in response to the available humidity.
Temperature for Wheat seed germination
Is between 12°C and 25°C, but germination is between 4°C and 37°C. Germination velocity is driven by accumulated temperature or degree-day. Degree-days are the number of the maximum and minimum average daily temperature levels for consecutive days. Wheat requires 35 degree-days to germinate clear seeds. For example, it takes 5 days before visible germination, at an average temperature range of 7 ° C. It takes 3-5 days at 10 ° C.
Water requirement for Wheat seed sprouting
Water is a key seed germination element. A mature seed is extremely dry and needs to absorb a considerable amount of water, relative to the seed’s dry weight, through a process of imbibitions. The minimum water content required for Wheat germination in the grain is generally about 35 percent to 45 percent by weight.
Crop germination is typically impeded by excess moisture primarily due to a restricted supply of oxygen. When seed imbibes water, enzymes are activated that break down reserves of stored food in the seed into metabolically useful chemicals.
Sowing time in Wheat cultivation
On the basis of temperature requirements, it was found that for indigenous wheat last week of October, for long-lasting dwarf varieties such as Kalyansona and Arjun, etc., first fortnight of November and for short duration dwarf wheat such as Sonalika, and Raj 821, etc., second fortnight is the best time to sow. Under exceptionally late sown condition, it can be delayed to the latest by the first week of December beyond which it can be practiced if the area is very small transplanting.
The spacing of Wheat seed
A row spacing of around 15 to 22.5 cm is practiced for irrigated, timely sown Wheat but the optimal spacing is considered to be 22.5 cm between the rows. A row spacing of 15 to 18 cm is optimal, under irrigated late-sown conditions. The planting depth shall be between 5 and 6 cm for dwarf wheat’s. Beyond this depth planting results in a poor stand. For conventional high varieties the sowing depth may be 8 or 9 cm.
The seed treatment procedure for Wheat
Solar or hot water treatment must be given to the seeds of loose smut-susceptible varieties. If the seed of Wheat is used for sowing, and not for human consumption or cattle feeding, it can be handled with Vitavax. Fungicide seed treatments, however, help to reduce losses caused by transmitted seed and soil-borne Wheat fungal diseases. Some seed treatment products include a fungicide which insecticide, and provide additional protection against insects such as aphids from the fall season.
When seeds are located in warm , moist soil, food materials become soluble in the seed and move into the embryo to feed it. The Soil Temperature controls the rate of this germination process. The embryo pushes out the seminal or seed root that is rising downwards. The root anchor drives the seedling into the soil and raises the obtainable surface area to draw water from the soil into the seedling. For this root to appear in plants located in good soil moisture a certain number of heat units are needed.
The minimum water content required for Wheat seed germination in the grain is by weight of 35 to 45 per cent. Seed germination may occur between 4°C and 37°C, with an optimal temperature of between 12°C and 25°C. Size of seed does not alter germination but affect production, development and yield of crops. For example, when compared to smaller seeds, bigger seeds have several advantages, the advantages are faster seedling growth, higher number of fertile tillers per plant and higher grain yield. The advantage of larger seeds is demonstrated when growing the Wheat crop under environmental stresses, particularly drought.
When crop emergence occurs, the seed embryo has 3 to 4 primordia leaves, and approximately half of the primordia leaf has already been initiated. The seminal roots grow first during the germination process , followed by the coleoptile which protects the first leaf ‘s emergence. The length of the coleoptile limits the extent of the sowing, and its length varies with the genotype, slightly increasing as the seeds are sown more deeply. Semi-dwarf Wheat, though, has shorter coleoptiles than tall Wheat.
From sowing to emergence, when soil temperatures are high, seedling mortality, and thus crop establishment, is a problem. The emergence of plants and the establishment of population are the starting points for the growth of Wheat crops. In hot climates, however, if the soil surface is bare and dry, and radiation intensity is high, the maximum soil temperature in the top centimeters may exceed the average air temperature range by 10 ° to 15 ° C. Under such conditions, with serious effects on the seedling emergence, the maximum soil temperature can reach 40 ° to 45 ° C. The initial plant population may fall below 100 plants / m which are considered deleterious to the yield of Wheat crops.
Seedling stage of Wheat
Wheat seeds need sufficient temperature and humidity during the seed germination process to germinate. Wheat seeds enjoy an ideal temperature range of 12 ° to 25 ° C. Seedling emergence occurs within 7 days under favorable conditions. The seedling must rely on energy and nutrients stored in the seed of Wheat before the first leaf becomes functional.
Different phases of Wheat seed germination
Germination of the wheat seed starts when the seed consumes water and finishes with the radical presentation. Germination has 3 stages;
- Water absorption (imbibition)
- Visible germination
The first process begins when the seed starts absorbing the moisture. In general, for germination to begin, a Wheat seed needs to achieve a moisture content of about 35 to 45 percent of its dry weight. The seed germination process can be initiated by water vapor as quickly as liquid can. Wheat seeds begin to germinate at around 97.7 percent relative humidity. Soil so dry that roots can not extract water has still about 99 percent relative humidity, much higher than dry seed. So even under dry conditions, the seed can get enough moisture to absorb and start the first phase, but it takes longer than under humid conditions.
When the embryo has swelled, releasing hormones that activate the development of the enzymes. The enzymes break down starch, and then store protein in the seed for sugars and amino acids, supplying the growing embryo with energy. The greater the seed of Wheat, the more starch it will have and, therefore, the strength it will provide. If the seed of Wheat dries out before the embryo begins to grow, this will remain viable. Phase 2 continues until seed coat breakup, the first visible sign of germination of the seed.
In this process the embryo begins to develop visibly. The radical appears, followed by other main roots and the coleoptile shortly after. The enzymes produced in Phase 2 mobilize in the seed stored sugars and amino acids and allow their transfer to the growing embryo.
Why Wheat may be slow to emerge
Deep Planting – Deeper than the ability of the coleoptiles to elongate, this can delay the emergence of seeds or cause problems with the establishment of stands. Varieties vary in their coleoptile lengths, but Wheat must be planted approximately 1.5 inches deep for the majority. Where the soil is not too restrictive and temperatures are in the ideal range, most plant varieties growing emerge at slightly deeper depths. Yet if deeper than around 2.5 inches of wheat is planted, it is likely that the wheat can not emerge.
Poor Quality Seed – A licensed laboratory checked the seed for germination and had an appropriate rate of seed germination, seed quality being no problem. If a laboratory did not conduct germination testing on the seed lot, low seed quality can be a concern if other possible issues have been ruled out. At times, Wheat doesn’t just germinate as the seed takes an exceptionally long seed dormancy. This is then hard to detect in the field and can cause producers to replant if it is not needed. Seed dormancy variations are numerous, but this has not been checked recently.
Insects – False wireworms may be responsible for poor seed emergence. False wireworms are up to 11/2 inches long, soil-inhabiting, yellowish to orange-colored worms. A pair of short antennae is clearly visible on the front of the head, and when viewed from the foot, the head area does not appear flattened. On dry soils they follow the drill lines, feeding on the seeds before germination.
Wheat harvesting – The wheat crop is harvested in March-April by cutting the plants with a sickle near the base. The next step is thrashing and this includes removing the grain from the bolt. Thrashing is performed by bullocks or thrashing machines below. The Wheat is winnowed and sifted following the thrashing cycle.
Yield of Wheat
Wheat Grain’s national average yield is approximately 12 to 13.8 quintals per hectare.
Commonly asked Questions on Wheat Cultivation
Does Wheat need sunlight to grow?
Wheat requires lots of suns, so it grows best in full sun, but if partly shaded, some parts of a field will well expand. It is a grass which makes use of the sun to create energy for development. More light, as long as the water and temperature requirements of the plants are fulfilled, usually yields better.
How often does Wheat need to be watered?
Suitable winter soil water Wheat is critical in the stage of flowering production. The root zone must be increased from 50 cm to 100 cm during this period and the soil water should not go below 60 percent of the available water. Wheat is a good crop during the season; it doesn’t take much water. Wheat requires 12 to 15 inches of rain over a growing season to yield a successful crop of Wheat.
How much time does it take for Wheat to grow?
Wheat is planted in the fall, typically between October and December, and grows to be harvested in the spring or early summer through the winter. Usually it takes about 7 to 8 months to achieve maturity and in spring gardens it produces quite a golden contrast.
What affects wheat production?
Factors influencing the percentage of establishment include management factors such as sowing width, row spacing, seed size, and application of herbicide, as well as soil moisture and temperature environmental factors. Wheat crop establishment is often affected by the emergence of pests and diseases.
What are the problems of wheat cultivation in India?
Wheat seed is mostly sown through broadcasting seeds. While it is the fastest way to plant, it has many inconveniences such as inadequate germination due to uneven seed depth, increased seed rate, uneven row distribution.
The conclusion of Wheat grain
If you are a commercial wheat grower, pick a high percentage of wheat grain germination from a quality seed.