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Sunflower

Sunflower was considered as an ornamental flower until 19th century after that it was cultivated as an oil seed plant in Russia.
The sunflower is a member of the compositae family. The commercial varieties cultivated for seed purposes are grouped under Helianthus annuus variety macrocarpus. The cultivated sunflower contains 34 somatic chromosomes (2n=34).


Utilization

Sunflower is mainly used for the extraction of oil. Defatted meal is the main by product of sunflower oil extraction and it is rich in protein and certain minerals. Defatted meal is mostly fed to animals and birds. The large seeded non-oil seed varieties normally provide feed for birds and also used as whole roasted seeds similar to peanuts. After dehulling, the kernels are sold as confectionery nuts.


Nutritive value

Sunflower oil has high level of linoleic acid. Linoleic acid is required for the cell membrane structure, cholesterol transportation in the blood and for prolonged blood clotting. Sunflower oil helps to reduce the serum cholesterol levels. The presence of trypsin inhibitor has been observed in sunflower seeds. However, the activity of the inhibitor is extremely low. The inhibitor is heat-liable and inactivated easily.

The chemical composition of sunflower seed is comparable to that of groundnut. However, the composition varies widely due to genetic and environmental factors. A proximate composition of sunflower seed is presented in Table 1.

Proximate composition (% of sunflower seeds)

Constituent

%

Protein

20.8

Lipid

54.8

Carbohydrates

18.4

Ash

3.9

(Source: Gopalan et al. (1982). Nutritive value of Indian foods)

Most of lipids in the seed are present in kernels (87%) followed by embryo (74%) and least in the hull. The dehulled seeds (kernels) contain more oil than the whole seed. Sunflower oil is primarily comprised of palmitic, stearic, oleic and linoleic acid. It contains more unsaturated fatty acids than other oil seeds such as soybean, peanut and cotton seed.

Recommended Varieties

No recommended variety is available. Spain, Sunfola, CO-2 and ANK-7 are identified as promising lines.
Field Establishment


Climatic requirements

Sunflower can be grown successfully in the dry zone as a rainfed crop in 'maha' season or as an irrigated crop in 'yala'.


Soils

Sunflower grows well on a wide range of well-drained soils from sandy loam to heavy clays.


Land preparation
Till land to a depth of 15-20 cm thoroughly.

Seed rate
13-16 kg/ha

Time of planting
Plant in late 'maha' (early January)
Irrigated planting can be sown in April to July

Planting and spacing
Between rows - 60cm
Within the row - 25 cm
Thin to one plant per hill when seedlings are about 2 weeks old.

Crop Management

Fertilizer use

Fertilizers are necessary for good yields. Nitrogen, the most important nutrient, is stored in the main stem and withdrawn when needed. Phosphate and potassium have an appreciable effect on yield only if sufficient nitrogen is available.

Basal- apply the following formulations and rates.

Urea - 50 kg/ha
TSP - 120 kg/ha
Muriate of Potash - 60 kg/ha
Top dressing - apply 50 kg/ha of urea at 4 and 8 weeks after germination.

Irrigation
Sunflower is more tolerant to drought than most crops but seed yields are higher under irrigated condition during flower development (about 7-8 weeks after emergence), rapid plant growth utilizes more moisture. To avoid moisture stress during this stage, the crop should be irrigated weekly if rain does not occur that often.

Weed control
One weeding at 2 weeks after planting is usually sufficient. Crop should be kept weed free for the first month after emergence.
Pest and diseases

Pest
Leaf-eating caterpillar (Spodoptera spp) is the only major pest damaging the crop during the vegetative phase of the crop. There are also few minor pests spp occur in the crop.

Disease
A fungal disease (Phoma) is observed when relative humidity is high. The disease damage the crop severely.

Pollination
Sunflower is cross-pollinated, normally by large insects such as honey-bees and wasps. Therefore, it is essential to introduce bee-hives to sunflower cultivation.

Harvesting & Post-harvest Technology

Yield
Rainfed 1-1.2 t/ha
Irrigated 1.8-2.5 t/ha

Harvesting

Most heads turn yellow at maturity
Harvest after petals drop but before seeds shatter.
After heads are dried in the sun, seeds can be separated easily by hand or multi-crop thresher with the capacity of 900 kg/ha.


Post-harvest handling

Drying of seeds is the first step in sunflower seed processing. The moisture content of freshly harvested sunflower seeds may be as high as 20%. To ensure safe storage, the seeds must be dried to less than 10% moisture. Sunflower seed is decorticated before the oil is extracted to ensure that the cake is a nutritious animal feed.

Extraction of oil from sunflower seeds or kernels can be done using general equipments and operating conditions used for soybean or other oil seeds. The extraction of oil from sunflower is done by mechanical extraction, prepress solvent extraction and direct solvent extraction methods.Sunflower oil usually does not require extensive refining as it contains relatively low
levels of free fatty acids, phopholipids, tocopherols, pigments and sterols.

 

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