Sunflower cultivation practices in Nepal

SCIENTIFIC NAME 

Helianthus annus 

Family : Asteraceae

CHROMOSOME NUMBER: 17 

❖ Sunflower is a common oilseed of India with wider utility. 

It is used as a source of edible oil, and as raw material for agro -based industry. 

It is a cross pollinated crop, insects (honey bees) are the pollinating 

agents. The crop has got two types of flowers viz. ray and disc florets. Seeds set in disc florets which are bisexual but exhibit self incompatibility due to protoandrous nature of the flower. 

• Open pollination under isolation is the common method of varietal 

seed production. • Varieties CO 1, CO 2, Morden, K1, K 2, EC 68414, EC 68415 

• In sunflower seed is multiplied adopting three generation system, as breeder seed, foundation seed and certified seed as the crop is often cross pollinated crop where the chances for genetic contamination is high. 

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Varietal Renovation Method (Pustovit Model) 

• In open pollinated variety, selection of superior plants are made based on the quality characters viz., plant yield, 100 seed weight and oil content. 

•The selected plants are harvested separately 

•Then they are raised in rows individually Seeds from promising plants are collected and this form the super-elite seeds. 

Causes for ill filled seed 

A. Pollination 

. It is a cross pollinated crop, normally the insect activity is less. For increasing the insect activity bee hives should be kept in the seed production plot in adequate quantities. The insect activity depends on the pollution and insecticides application. If insect activity is less that leads to poor seed setting and formation of ill filled seeds. 

B. Development of axillary flowers 

Normally the axillary flowering takes place during the summer because of the high intensity of light. So these type of axillary buds receive the nutrients and assimilate whereas the main head does not get the required quantity of assimilates for seed set there by ill fillings occurs. 

C. Self incompatibility 

• Presence of self incompatibility in sunflower also leads to poor seed set and ill filled 

seeds. 

Season And Land Requirement 

• April to May is highly suitable for irrigated seed crop. The flowering 

should not coincide either with rain or high RH as it will wash out the 

pollen and the maturation should coincide with dry weather. 

• Three to four ploughing and disking's are sufficient for preparing the land. 

• Soil should be moist at least 10cm deep before sowing and this condition necessitates good soaking rains or irrigation before sowing. 

• The land should be fertile and problem soils will lead to low pollen fertility and will adversely affect the quality and the seed set will be poor. 

• The previous crop should not be the same crop to avoid the occurrence of volunteer plants and if to be the same crop it has to be the same variety and should be certified and has to be accepted for certification. 

• The field should not have any volunteer plants. 

Field Standards (Isolation) Sunflower field should be isolated from contaminants as follows. 

Contaminants 

Fields of other varieties and the same variety not confirming to varietal purity requirements for certification and wild sunflower 

Foundation seeds (meters) Certified seeds(meters) 

400m 

200m 

In sunflower differential blooming dates for modifying the isolation distance 

is not permitted 

Seed and sowing 

• For production of foundation seed, breeder seed is used as the base material, while for certified seed, foundation seed should be used as the base material. 

• The seed used should be from authenticated source with tag and 

bill. 

• The required seed rate will be 8-10kg/ha or 3-4kg/ acre. (Morden 

80kg/ha) 

• The seeds are sown at a spacing of 30 x10 cm for the variety morden and at a spacing of 60x20 cm for other varieties and are dibbled at a depth of 2-4cm. 

• In the main field seeds are sown either in ridges and furrows or 

under beds and channels. 

Presowing seed treatment 

• The seeds are given with any one of the seed treatment or in 

combination. 

• Fresh seeds of sunflower exhibit physiological dormancy which could be broken by soaking the seeds in 300ppm ethrel for 8h or 0.5% KNO3 for 16h. Moist hydration of seed with water for 24h followed by dry dressing with thiram @2g kg-1 of seed improved 

the productivity of the seed. 

• Seeds are soaked in 2% ZnSO4 for 12h with a seed to solution ratio of 1:0.06 and are dried back to their original moisture content of 8 9% This management could be used both for dryland agriculture as well as gardenland. 

Nutrient application 

• At last ploughing apply 12.5 tonnes of compost per hectare. 

• The fertilizer requirement of seed crop is 80:40:40 kg of NPK, 

• In which 40kg of N and full dose of P and K is applied as basal, while 40kg of N is applied at the time of earthing up i.e. 40-45 days after crop growth. 

• The seed crop is also sprayed with 2% DAP or 20ppm NAA at 30 and 60 days after sowing. • In case of deficient soils the crop is sprayed with 0.5% Borax at 

button formation stage. 

Weeding 

• Apply of fluchloralin@ 21/ha as pre-emergence herbicide to control 

the growth of weeds up to 20-25 days. • One hand weeding is done at the time of button stage to keep the field free of weeds. 

• Weeding after head formation stage is not economical. 

• On organic production, 2 hand weeding at seedling stage and other at boot leaf formation will keep the field weed free. 

Supplementary Pollination 

• Due to lack of honey bees, seed setting will be poor. Hence critical or additional pollination is given to the crop for effective seed setting by Rubbing the heads of two neighbouring plants with each other. 

• It is done during mid flowering stage (i.e 58-60 days of planting for long 

duration varieties and 45-48 days for short duration varieties) at alternate 

days between 7-11 a.m for 2 weeks. 

• Hand pollination: The heads are rubbed with palm or muslin cloth so 

that pollination can be enahnced. 

In hybrids, the palm is first gently rubbed on the male parent flowers and 

then on the female line to transfer the pollen. 

Keeping of bee hives 5 ha-1 

• At head opening stage 2 % D.A.P and 20 ppm N.A.A. sprayed 2 times on 

30th and 60th day after sowing for effective seed setting. 

Irrigation 

• The crop should be irrigated once in a week for enhanced seed set 

and formation of bolder grains. • The critical stages of irrigation are primordial initiation stage, vegetative stage, milky and maturation stage. 

• If the irrigation is withheld in these stages seed set will be poor and 

seed size will be reduced. 

Pest and Disease management 

Common pests and diseases 

Cut worm 

White fly 

Thrips 

Tobacco caterpillar (Spodoptera litura) 

Capitulum borer (Helicoverpa armigera) 

Alternaria blight and leaf spot 

Rust 

Downy mildew 

Head rot 

Management techniques Chlorpyriphos (20EC) @ 3.75 l/ha 

Imidacloprid @ 0.1ml/lit 

Phosphomidon 0.03% 

Endosulphan 0.07% or NSKE 5% or Fenitrothion 0.05% 

Endosulphan 0.07% or Helicoverpa NPV @ 250 LE/ha. 

Mancozeb 0.3% 

Zineb 0.2% 

Metalaxyl 25WP 

Copperoxychloride@0.4% or mancozeb 0.3% combined with endosulfan (0.05%) 

Rouging 

•Plants rogued from their vegetative phase to harvesting, based on plant, height, head size, branching habit, number of heads and colour of seeds. 

Sunflower seed production Nugurusaichandan 

Factor 

Off types at and after flowering 

Objectionable weed 

Plants affected by downy mildew 

Plants infested with orabanche 

Field standards 

Foundation seed 

0.10% 

None 

0.050 % 

Certified seeds 

0.20% 

None 

0.50% 

None 

None 

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Seed Certification 

Number of Inspections: 

• A minimum of three inspections shall be made as follows: 

1. The first inspection shall be made before flowering on order to verify isolation, volunteer plants, and other relevant factors, 

2. The second inspection shall be made during flowering to check isolation, offtypes and other relevant factors 3. The third inspection shall be made at maturity and prior to harvesting to verify true nature of plant and other 

relevant factors 

Harvesting 

• Change of thalamus color from green to yellow is the visual 

symptom of physiological maturation. 

• Heads are harvested as once over harvest. 

Threshing and Drying 

The earheads are dried under sun and threshed with fliable stick for extraction of seeds The moisture content of seed at the time of threshing will be 15-18%. On large scale production sunflower threshers are used, but care should be given to avoid mechanical damage, which in turn will reduce the seed quality and storability. 

• The seeds are dried to 8-10 % moisture content either under sun or adopting mechanical driers for long term storage as the seeds is orthodox in nature. 

Seed treatment and Packing 

• The seeds are infested with several storage pests, to protect against these pests the seeds are given protective treatment with bavistin @2g/kg of seed. 

• Seeds are packed in gunny bag for short term storage while in HDPE 

and polylined gunny bag for long term storage. 

Storage Of Seeds 

• The treated seed can be stored up to 10 months provided the seeds are not infected with storage pests. Seed can be stored up to 2 years if the seeds are packed in 

moisture containers and are stored at low temperature. 

•The godown should be kept clean as the possibility of secondary infestation with Trifolium (red flour weevil) is much in these crop.