Production constraints in sunflower

Introduction

• Sunflower was introduced in India during 1969 and to start with four Russian varieties and one Canadian variety were evaluated in various parts of the country.
• The commercial cultivation of this crop started in 1972. Presently, the crop is cultivated in an area of 17.1L. hectares with a production of 9.4 L. tonnes .
• The crop is fourth most important oilseed crop in the country after groundnut, rapeseed-mustard and soybean.
• The phenomenal increase in area and production of sunflower in the country since its introduction is due to following merits of the crop.
• Wide adaptability or wide-ranging agroclimatic conditions and soil type.
• Short duration (90-100 days) which enables fitting in different cropping systems.
• Photo-insensitivity which enables its cultivation in rainy, post-rainy and spring/summer seasons.
• Availability of varieties/hybrids with diverse duration and high yield potential which enables the crop to fit into multiple and intercropping systems.
• Easy cultivation and crop management.
• High seed multiplication ratio of more than 1:80.Drought tolerance and the ability to revive rapidly after prolonged period of drought.
• Ideal crop for contingency plans.Remunerative market price.
• Good quality oil with high polyunsaturated fatty acids and non-cholesterol properties.
• The increase in the productivity of the crop during the last 7-8 years was mainly due to continuous increase in sunflower area in high productive zones in North India.
• If one considers the changes in sunflower productivity in traditional areas of Karnataka, Maharashtra and Andhra Pradesh (erstwhile) which account for nearly four-fifths of total crop area, the situation is really not gratifying.
• The crop suffers from major production constraints of different kinds mainly in these traditional areas.

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Planting material constraints

• Use of quality seeds of improved varieties/hybrids is an important input for high productivity.
• Presently, nearly 70-80 per cent of the crop area is covered by hybrids.
• Most of the hybrid seeds is produced by private industries where it is not possible to check the quality of hybrid seeds.
• Many unscrupulous producers sell seeds of poor quality to unsuspecting farmers leading to poor crop and yields.
• Likewise, with varieties, farmers tend to continuously use their own seeds leading to deterioration in the quality of seed.
• Although adequate quantity of breeder seed is produced, due to poor seed multiplication chain, the amount of certified seeds produced is not adequate.

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Crop adoption constraints

• The very advantages/merits associated with sunflower have in fact worked against the crop leading to poor productivity levels.
• The crop has been taken to marginal and sub-marginal lands of all types where it is possible to provide favourable environment for high productivity.
• Likewise, because of photo-insensitivity of the crop, we find the planting of crop by farmers at all times of the year in some areas which again is not ideal.
• Despite photo-insensitivity of crop, there are certain limits within which the crop needs to be planted for high yields.
• The planting time has to be adjusted in such a way during rainy season that flowering period does not coincide with continuous drizzling and cloudy weather that causes pollen indehsicence, poor seed set and low yields.

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Crop husbandry constraints

• This is one of the major production constraints specially under rainfed conditions.
• It is always a common sight to find gapy or crowded plants stands of sunflower on farmer's fields.
• Due to poor quality seeds or insufficient moisture, gaps are observed which lead to sub-optimum yield levels.
• If the germination is normal, with recommended seed rate one can expect at least 50 per cent more plants than the recommended plant stand.
• These excess plants need to be thinned in time which is normally not done by many farmers leading to low yields.
• Likewise, many times proper spacing, timely weed control are not followed which again reduce the yield levels.

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Nutrition constraints

• Sunflower is an exhaustive crop.
• The average nutrient removal by crop to produce a tonne seed yield of sunflower is 63.3 kg N, 19.1 kg P2O5, 122.6 kg K2O, 11.7 kg S, 68.3 kg Ca, 26.7 kg Mg, 47 g Zn and 1075 g Fe.
• However, in most cases, there is a large gap between nutrients applied and nutrients removed leading to depletion of soil nutrients and unsustainable production.
• This seems to be one of the probable reasons for a declining trend in yield of sunflower crop reported/observed in many traditional sunflower growing areas.
• If we visualise a farmer continuously growing sunflower for the last 20 years, with yield level of around 600 kg/ha, and without any application of potassium, nearly 1471 kg K2O/ha must have been depleted from soil.
• Similar depletion from soil resources is taking place to varying degrees with respect to many nutrients leading to unsustainable yield levels.

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Plant protection constraints

• Sunflower is affected by a large number of insect pests and diseases although only a few of them are economically important.
• In India, more than 50 insect species have been found feeding on sunflower.
• However, capitulum borer, Bihar hairy caterpillar, tobacco caterpillar, green semilooper, cabbage semilooper, leaf hopper, aphids, whitefly, cut worm and thirps are important insect pests.
• Losses up to 30% from seedling pests, 46% from sucking pests and 50% from inflorescence pests have been reported.
• Even defoliators can be very damaging sometimes.
• Appropriate management practices need to be standardised and practised to manage different insect pests.
• Among the diseases like downy mildew specially in Marathwada region of Maharashtra, alternaria blight and leaf spot (15-90% yield loss with 20-30% oil loss) are very important.
• In addition, diseases like powdery mildew, bacterial leaf spot, rhizopus head rots, botrytis head rot, root and collar rots, vascular wilts etc., may at times cause considerably yield losses.
• Sunflower is prone to severe damage by diseases especially during rainy season when there is high rainfall and high humidity, and any effort to stabilise crop productivity can not be successful until suitable disease management practices are followed.
• In addition to the above, parakeets, doves, crows, rats etc., also may cause severe damage on sunflower crop leading to poor yields.
• When the crop is taken on large areas, the severity of these problems will reduce although in off-season crop production, special efforts need to be made to protect the crop.

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Seed setting constraints

In sunflower more ill-filled grains are formed due to poor seed setting since this is highly a cross pollinated crop. The main reasons for poor seed setting are;

• Use of impure and qualities seed.
• Due to less population of honey bees impairs cross pollination.
• Due to heavy rains at flowering stage and high humidity pollen grains are washed off.
• Because of high temperatures prevailed at the time of pollination the pollen grains will be dried up.
• Due to lack of sufficient soil moisture at seed setting.
• Due to deficiency of phosphorus and micro nutrients.
• Excess nitrogen application.
• Due to insect, disease and bird damage.
• In sunflower, seed setting starts from periphery to centre of flower, which normally completes in 10 days. As seed setting is progressing the non-availability of both macro and micro nutrients is required proportions is one of the reason for poor seed setting.

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Steps to be taken up for proper seed setting

• Decide optimum seeding period in such a way that the flowering should not coincide with extremes of temperature, heavy rainfall and fog.
• Use only pure and quality seed of high yielding varieties or hybrids.
• Follow only recommended fertilizer schedule.
• Avoid excess use of nitrogen, see that there is no phosphorus deficiency. At the crop age of 30 days there should not be any deficiency of N. Rectify the deficiency of micro nutrients if observed.
• If sunflower is grown as rainfed rabi crop in heavy soils grow nearby fields of safflower or safflower as intercrop so that the activity of honey bees can be increased.
• Honey bees are attracted by yellow flowers and the honey dew available in flowers of niger. Hence grow niger around the field of sunflower so that fertilization can be improved.
• Establish more plant population per unit area, otherwise large sized flowers are produced cause poor seed setting in the centre of the flower.
• Grow the crop if possible east to west to avoid shading of one row on the other.
• Keep 2-3 honey bee colonies to activate honey bee activity and to increase crop pollination. It also gives additional income from honey.
• See that there should not be any moisture stress from bud formation to flowering and milking of seed stages.
• From flowering on wards necessary plant protection measures are to be taken and also bird scaring.
• During flowering period spray insecticides mostly during evening periods.
• Spray cycocel 50 ppm at 40 and 60 days age of crop to increase yield through better seed setting.
• Rub the flowers of opposite lines at flowering period between 8-11AM and 3-5 pm to obtain more cross pollination.
• Rub the flower with smooth cloth or cotton at flowering time between 8-11 am on every day or on alternate days for 10-15 days to increase cross pollination. This operation give 25% higher yield. At the time of rubbing if tobacco caterpillar or gram caterpillar observed on flowers better pick then and destroy to reduce the crop damage.

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