MAZAO

WHEAT PRODUCTION (UZALISHAJI WA NGANO)

INTRODUCTION
Wheat (Triticum spp) is a cereal grain from the Levant region of the Near East (eastern Mediterranean) and Ethiopian Highlands but now cultivated worldwide. Wheat is one among the most important cereal crop produced in the world.
Wheat is grown on more land area than any other commercial crop and is the leading source of cereal protein in human food having higher protein content than either maize or rice
Areas of Wheat Production in Tanzania
Arusha – Karatu and Monduli.
Manyara – Basuto
Njombe – especially Makete district.
Mbeya – Mbozi
Tanga – Usambara

Taxonomy of Wheat (Botanical Classification Some of Wheat Varieties grown in Tanzania are:-
Azimio 87 - its grain colour is red and matured at about 110 up to 120 days.
Viri its grain colour is white and mature at about 110 up to 120 days.
Juhudi its grain colour is white and mature about 95 up to 100 days.
Selian 87 its grain colour is white and mature about 125 up to 130 days.
Njombe 07 its colour is red and mature about 125 up to 120 days
Data from MATI-UYOLE, MBEYA

BIOLOGY (BOTANICAL DESCRIPTION) OF WHEAT CROP

Wheat is one of annual cereal crop which is grown in areas with low temperature (in temperate region but not typically temperate). It develops to a height of 1.0 – 1.5 m, although it may depend on variety used.
The fruit is a caryopsis, commonly called the “grain” or the “seed”.
Wheat is self pollinated but sometime it can be cross pollinated

Description of Wheat Crop Parts
Kernel The kernel is the seed of the wheat plant and is housed in the head (spike of an immature plant)
The kernel, or wheat berry, is composed of three parts:
o The endosperm (soluble fiber),
o The bran (insoluble fiber).
o The germ (the sprouting section of the seed
The material which protects the wheat kernel is called Beard
The Stem Wheat grasses have stems that upkeep the head of the plant. The nature of stems are hollow and ones the kernel have been harvested are called straw. Some farmers grow wheat for straw fabrication only. Straw is used as mulch, animal bedding and feed, and decoration.
Leaves The leaves of the wheat grass plant are long and thin. They protect the head of the plant and gather light for photosynthesis. The main protector is called the flag leaf. It is the topmost and youngest leaf on the stem. The flag leaf emerges when at least three nodes (joint stems) are noticeable above the soil and provides proof of a plant's maturity.
Roots The roots' main purpose is to gather nourishment from the soil so the wheat plant grows strong and healthy.. The primary root system begins when the seed germinates and provides nutrients for the wheat seedlings. Deep and fast root growth is ideal
As the plant matures, the secondary permanent root system replaces the primary root system and provides stability.
Tiller
The first tiller to emerge is the ones formed between the axils of the coleoptiles and the first true leaf. A rapid increase in tiller number occurs with warmer spring temperatures. There are several tillers on each plant; the number depends on such factors as variety, seed rate, soil fertility and the rain fall at the time of tillering.
Spikelet This serene of the flowers called florets, this vary from one to five. Florets in each spikelet are enclosed by two glumes. The fruit is oval with a central groove on the ventral surface and a terminal tuft of hairs

ECOLOGICAL REQUIREMENTS FOR WHEAT PRODUCTION

Climatic Requirements
Humidity
The optimum relative humidity required for wheat is 50-60%. If relative humidity is less than this then moisture loss occurs due to heavy evapotranspiration and it results in more water requirement for irrigation. Disease increase when there is high humidity coupled with high temperature
Rainfall Requirement for Wheat
Wheat is cultivated in the region where annual precipitation occurs from 250mm to 1750mm. though 75% wheat area falls where annual rainfall precipitation occurs between 375mm to 875mm. Regions with 625mm to 870mm rainfall are most suitable for wheat cultivation. Rainfall at time of maturity cause severe losses to wheat crop affecting yield and seed quality adversely
Temperature Requirement for Wheat
The temperate requirements of the wheat plant during the spike development, pollination and grain filling stages has a significant bearing on the choice of a suitable planting date as temperatures outside the physiological limits at these stages may significantly affect yields. Spike-elongation increases linearly when the air temperature increases from 10°C to 30°C. The optimum temperature for pollination is between 10°C and 25°C with a minimum of 10°C and a maximum of 32°C. Temperatures outside these limits result in yield losses due to pollen sterility and the deformation of the pistil and stamens.
However it requires different temperatures at different stages of plant growth and development. Temperature requirement may slightly differ from one variety to another at the time of germination, however general minimum temperature is required from 3.5 – 5.50C and optimum 20 – 250C and maximum temperature is 350C. On temperature below or above the optimum, germination of seeds decreases slowly
Soil or Edaphic Requirements
Soil Characteristics
Soil texture - For best yields wheat needs well drained soil with a high nutrient content. It yields very poorly in water logged conditions. Wheat can be established on flats or raised bed with zero tillage situations. Conventionally, wheat is planted after several ploughing, disking and planting operations.
Soil pH – Wheat prefers to grow in soil that has a pH between 5.4 and 5.8

Soil Fertility
Wheat is very sensitive to insufficient nitrogen and very responsive to nitrogen fertilization. Nitrogen is the structural component of protein, the most important building substance from which the living material or protoplasm of every cell is made, chlorophyll formation. Insufficient nitrogen results in light colour, reduced tillering and disturbance of normal cell growth division, decrease rate and extent of protein synthesis.
Excessive nitrogen causes lush succulent growth, resulting in greatly increased danger of lodging, delayed maturity and greater susceptibility to diseases such as rusts septoria and powdery mildew. Generally the soil should be fertile

AGRONOMIC PRACTISES

CROP ETABLISHMENT
Land Selection
Wheat is most productive when planted on soils that have good surface and internal drainage, a fertility level of at least medium and a neutral of slightly acidic soil.
Fields that have poor surface or internal drainage or that are subject to prolonged overflow should not be planted with wheat. Test soils to determine fertilizer and lime needs well before planting time.
CROP ETABLISHMENT
Seedbed Preparation
Seedbed grounding should be thorough enough to incorporate existing vegetation and permit unvarying establishing of a crop. Plowing may be required where excessive vegetation exists as when following corn or grain sorghum with wheat.
If little vegetation is present, disking may provide a good seedbed and allow proper drill operation
Planting of Wheat
Planting with a grain drill is the preferred method because it allows uniform depth of planting and results in a more uniform stand. Broadcast seeding followed by light disking or harrowing to cover the seed can be used where drilling is not convenient.
Planting depth should range from 2 to 5 cm; row spacing of 30 to 90 cm is recommended, depending on available water and planting density of 70 to 90 kg seed/ha under dry land and 100 to 150 kg seed/ha under irrigation. The seed should be planted evenly and shallowly in a moist,
firm seedbed. A no-till planter can be used for seeding or a planter fitted with tines can be used for planting.
Planting with a no-till drill may be successful if the surface is smooth and little vegetation is present. Planting wheat earlier than the recommended planting dates will subject the plants to greater insect and disease pressure and also make the plants more prone to winter injury.
Although wheat emerges sooner and the shoot develops faster in warm soil (23.9 to 32 o C), the root system develops much faster and more extensively if the soil is cools (12.8 to 15.6 o C).
Cultural Control Methods
Weeds are often effectively controlled using cultural practices that result in rapid wheat emergence and development. Recommended cultural practices include the following:
1) Planting certified seed (free of weed seeds and garlic bulblets)
2) Good seedbed preparation including free of emerged weeds at planting
3) Proper fertilization
4) Seeding at the proper rate and time
5) Management of diseases and insects
Fertilizer application
It is advised that nitrogen should be applied at planting. Direct contact between seed and fertilizer should be avoided. Excessive fertilizer application of nitrogen should be avoided owing to luxuriant vegetative growth with the resultant lodging. If recommended, incorporate Phosphorus and Potassium into the seedbed before planting time. Split applications are recommended for sandy soils for maximum productivity. Potassium deficiencies are seldom observed in the wheat production areas
Irrigation
Irrigation scheduling must be according to evaporation and needs, as per growth stage. It is, however, very important that irrigation is not stopped too early and the last irrigation must be applied when the total plant is almost stained. This is to ensure an even ripening and to produce grain with a high percentage plumpness and acceptable nitrogen content.
Proper irrigation scheduling can also minimize lodging and disease occurrence and optimize yield quality. The method of irrigation will depend on the water availability and the available irrigation equipment.

Weed control
Planting must be done on a clean field. This will avoid unnecessary weed control during early seedling growth. Weeds can harbor deleterious insects and diseases and decrease harvest efficiency. The presence of weedy plant fragments may also reduce the food and feed value of wheat. These factors result in dockage and lower yields thereby reducing profits.
As soon as the crop has covered the soil surface, the chances of weed to develop are minimal. However, any weeds during seedling stage should be eradicated. Weeds can be controlled chemically or mechanically or by cultural methods. Mechanical control needs to be done judiciously to avoid seedling injuries.
Pest Management
Some of these pests cause damage that results in reduced yield, reduced grain quality and lowers the price received for grain.
Planting resistant varieties; following recommended planting time, cultivation, and fertilization guidelines; crop rotation; planting high quality, weed-free seed; timely field inspection and pesticide applications are all part of an efficient and effective pest control program. Continuous damage without treatment results in reduced yield or zero yields. Wheat is susceptible to various kinds of pests that negatively affect the vegetative growth, flowering, pod filling, water and nutrient cycle of the plant
. Major pests are
 American bollworm,
 Aphids (green and brown),
 Black maize beetle
AMERICAN BOLLWORM
The moths fly at sunrise and sunset and lay their eggs directly on the plant. The young larvae of previous generations feed on the chlorophyll of the leaves and later migrate to the spike to feed on developing grain. The colour of the final stage larva can vary from bright green to brown and it has a distinct white lateral line on both sides. The larva can get as long as 40 mm and can cause considerable damage.
Damage
Direct as well as indirect yield losses can occur on account of damaged grain with the consequent downgrading of the grain.

Control/Management.
Under dry land conditions, chemical control can be considered when three to four larvae are found per walking meter. Under irrigation, the threshold value is six to seven larvae per walking meter. Only registered chemical agents must be applied and the label instructions must be followed.
BLACK MAIZE BEETLE
The female beetle lays approximately seven to ten eggs in the soil and the larvae develop in three instars, followed by a pupal stage. The adult beetles inflict the most damage. The larvae survive on organic material in the soil.
Damage
Beetles chew on the base of the seedling stem which causes a decline in the stand.
Control
Given the mobility of the adult beetle, seed treatment agents are registered as a pre-planting method of adult beetle population management.

DISEASES OF WHEAT

Stripe rust (Yellow rust)
The disease is caused by the fungus Puccinia striiformis . The disease-causing fungus is an obligate parasite and can therefore only survive on living plant material. Stripe rust requires cool and wet conditions to infect the crop. Free moisture on the leaves and an optimal temperature (10-15°C) are required for infection
Symptoms
 elongated,bright yellow to orange stripes which consist of rust pustules that run parallel to the leaf veins.
 The stripe formation is less distinguishable on the younger leaves and the rust pustules appear more in spots on the leaf.
 Under very favourable conditions for the development of stripe rust, the leaf veins, glumes, beards and young kernels can also be infected.
Control
Chemical control must be applied after correct disease identification, confirmation of cultivar susceptibility and with accompanying favorable environmental conditions for the spreading of
the disease. Use of resistant cultivars – some varieties resistant to stripe rust (yellow rust) has been developed.
Leaf rust (Brown rust)
Leaf rust is caused by the fungus Puccinia triticinia (previously called Puccinia recondite f. sp. tritici). The spores require 15 to 20ºC temperature and free moisture (dew/rain/irrigation) on the leaves to successfully infect wheat. The first signs of the disease (sporulation) occur 10-14 days after infection
Symptoms
Pustules (containing masses of urediospores ) are dark reddish brown, and may occur on both sides of the leaves, on the stems, and on the spikes. With light infections the pustules are usually separate and scattered, but with heavy infections they may coalesce. Prior to pustule formation, "flecks" may appear. Before the spore masses break through the epidermis, the infection sites feel rough to the touch; as the spore masses break through, the surface tissues take on a ragged and torn appearance.
Control Removal of volunteer wheat plants, which forms a green bridge for the fungus through the summer, can eliminate or delay the onset of leaf rust.
STEM RUST (Black rust)
The fungus responsible for stem rust is air-borne and distinguished by the appearance of large, elevated reddish brown rust spots on the leaves, leaf veins, ears, beards and stems of susceptible cultivars.
Symptoms
The appearance of elevated, oval shaped, reddish brown spots on the wheat tillers and/or peduncle. Infection will take place when dew and/or misty wet conditions are accompanied by temperatures of 15°C to 24°C.
Due to its preference for higher temperatures, stem rust usually appears later in the season when the wheat plant is already in the grain filling stage. Under favorable conditions for the development of stem rust an entire yield loss can occur.
Control
Chemical control of stem rust can only be successful if the tiller area is covered properly with the fungicide. The risk of rust infection can be minimised by planting resistant cultivars

Yellow spot (Tan spot)
Symptoms
Tan-brown flecks turning into yellow-brown oval-shaped spots/lesions surrounded by yellow margins may expand into 10-12 mm in diameter. Large lesions coalesce with dark brown centres. Spot develops on both sides of leaves. Temperature from 20ºC to 30ºC and free moisture favours disease development.
Control
In susceptible cultivars yellow spot can cause up to 30% yield losses. A break from wheat-on-wheat (crop rotation with non-host crops) can reduce the risk of yellow spot. Sow resistant varieties.
GLUME-BLOTCH
Glume-blotch is caused by a fungus and symptoms may appear on the leaves and ears. Conditions favorable for disease development include periods of six to seven hours of dew and/or rain accompanied by high humidity and temperatures above 7°C. Glume blotch is at its most damaging when infection occurs between flag leaf emergence and flowering.
Symptoms
The appearance of brown spots on the ears. Lesions usually appear on older leaves, are brown, lens shaped and encircled by necrotic and/or chlorotic leaf tissue
Control
Cultivar resistance.
Crop rotation. Removal of harvest residue by ploughing or burning. Chemical control can help to control the disease.
FUSARIUM HEAD BLIGHT:
Fusarium head blight is caused by fungi of the genus Fusarium where Fusarium gramenearum is identified as the primary disease-causing organism under local conditions. This disease is especially prevalent in irrigation systems where wheat is alternated with maize, but can also occur during wet seasons under dry land conditions.
Symptoms
Infection of one or more glumes in the spike during flowering and further spreading of the fungus to adjacent glumes can cause parts of the spike turn white or "bleach" and die off early. The result is no grain at all or small, shrivelled kernels on infected parts of the ear. Under wet,humid conditions, there may be a pink discoloration of infected parts of the ear due to fungal growth.
Control
The crop rotation with non-host crops as well as the destroying of wheat and maize stubble. Preventative ear spraying during flowering can help to lower the infection to inhibit disease development LOOSE SMUT
This fungal disease appears in all wheat production regions. Loose smut development is favoured by cool, humid environmental conditions which lengthen the flowering period of the plant.
Symptoms
Infected spikes are visible as black to dark brown spore masses which have replaced the spikelet. When spores have been blown or washed away only the rachis remains
Control
This disease can be avoided by the use of certified seed that has been treated with a fungicide.
HARVESTING OF WHEAT
Modern and traditional methods of wheat harvest technology often depend upon the scale of production. However, in many small-scale farming situations, reaping by hand-cutting of plants or cycling, stooking, shocking, sheaving, and stacking of straw is common.
Wheat should be harvested without delay when it reaches maturity and begins to dry down to market moisture contents. Wheat grain must be harvested before shattering, pre-harvest sprouting, bird damage or weathering, to minimize pre-harvest losses, yet must be dry enough for storage. Alternately, grain may be harvested at moisture content higher than is safe for storage, by reaping or swathing the grain and allowing it to dry in windrows, sheaves, stooks, shocks or stacked.

HARVESTING TECHNIQUES

 Reaping by hand-cutting of plants
 By using Combine harvesters
Combine harvester is a machine which combines three separate functions of Reaping, threshing, cleaning (winnowing) into a single piece of equipment.

POST-HARVEST OPERATIONS
Transportation
The harvested wheat can be transported home after or before being threshed by either carts or Lorries depending on farmer’s resources
Threshing
Can be done on the farm or at home depending on the scale of production as well as distance from farm to home.
The next activity is threshing, upon need of grain for food or sales, by stationary mechanical threshers or on oxen-trodden mud-packed threshing floors. During threshing, cracking and breaking the grain should be avoided since damaged grain invites greater damage from storage moulds and insects, and reduces marketability.
Winnowing
Winnowing is done by tossing the grain into the air where by chaff and empty grains will be blown away by a moving air (wind).
Packing and Storage
On-farm storage of grain is common for smaller scale farmers, whereas direct sales to cooperative, government or private elevators are the norm for larger producers.
STORAGE PESTS
Confused flour beetle (Tribolium confusum)
Beetles and larvae feed on undamaged and broken kernel. Common mill pest. Flour develops sharp odour if badly infested.
Khapra beetle (Trogoderma granarium Ev).
The larva is a very serious stored product pest, the beetle does no damage. The grains are often hallowed out until only the husk remains.
Rats (Rattus spp.)
Rodents feed on whole and broken grains, flour etc. They spoil more wheat than they eat by contaminating it with hair, urine and faeces.

ECONOMIC IMPORTANCE OF WHEAT

Globally, wheat is the leading source of vegetable protein in human food, having higher protein content than either maize (corn) or rice, the other major cereals. Straw utilization has become increasingly important in the economic value of wheat production. There are many uses of wheat straw such as; residue for conservation tillage, landscaping, residue to reduce soil erosion during road or building construction, mushroom production, horse bedding, hay feeding and others.
In terms of total production tonnages used for food, it is currently second to rice as the main human food crop and ahead of maize, after allowing for maize's more extensive use in animal feeds. Wheat grain is a staple food used to make flour for bakery purposes. It is also fermented to make beer and biofuel
Wheat is planted as a forage crop for livestock and its straws can be used as construction materials for roofing thatch. It provides vitamins, minerals, protein and starch.
The processed wheat products.



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