The hybrids have the following advantages over open pollinated varieties
- Hybrids have high yield potential and are responsive to higher inputs.
- They are superior in their seed filling ability and are comparatively more self fertile.
- They are more tolerant to diseases and pests.
- They have higher drought tolerance.
- The production and availability of quality seed assumes tremendous importance for realising higher sunflower yield on a commercial scale.
- The production of high quality basic, breeder, foundation and certified seed of hybrids and their parental lines calls for careful planning and management on the part of the seed producer.
- Although sunflower thrives well on a variety of soils, well drained and neutral soils are best suited for its culture.
- The field selected for seed production should, however, not have been put under any sunflower crop in the preceding 2 - 3 seasons.
- The field should be thoroughly prepared to ensure even and weed free seed bed.
- Avoid low lying areas and make necessary provision for surface drainage through adoption of recommended soil and water conservation measures particularly in soils which are ill drained.
- Two to three ploughings followed by harrowing / planking in case of black soils should be adequate to achieve the required seed bed conditions.
- For case of irrigation, form ridges and furrows as per suggested spacings.
- The seed production plots should be kept free from weeds during the first 40 - 50 days of crop growth.
- This can be achieved by good seed bed preparation and timely weeding and interculture. For this purpose, give 2 hoeings at intervals of 15 days commencing from 15 - 20 days after emergence combined with manual weedings.
- Weeds can also be put under check through timely chemical weed control. Whenever necessary, apply prometryne or lasso (Alachlor) as pre - emergence spray @ 1 kg / ha in the former and 1.5 kg a.i. in the latter case immediately after sowing or on the next day.
- For better control of weeds ensure that there is adequate moisture in the soil at the time of weedicide application.
- All off types which do not conform to the specific population / parental line should be removed before flowering / pollination.
- Pollen shedders or male fertile plants in the A line which are easily identifiable by their dark anthers and sterile plants in the B line should be removed.
- To accomplish this, carry out the roguing operation 2 - 3 times preferably before anthesis.
- Apply irrigation as and when required at intervals of 6 - 10 days in light textured soils and 15 - 25 days in heavy textured soils.
- The actual timing and number of irrigations, however, depend on seasonal rainfall, soils and moisture status.
- Care should be taken to see that the crop does not suffer from moisture stress at critical crop growth stages viz., bud stage (30 - 40 days after sowing), flowering (50 - 65 days after sowing) and seed filling (65-95 days after sowing).
- Farm yard manure / compost 7 to 8 tonnes / ha.
- Broadcast well decomposed FYM / compost, 20 - 25 days before sowing and incorporate it thoroughly in the soil.
The recommended doses of nutrients for seed production plots are given below;
- Apply 50% of N and the entire dose of P2O5 and K2O at the time of planting preferably as band placement by the side of seed rows.
- The remaining 30 kg N/ha may be applied as top dressing in two equal splits of 15 kg / ha each, first at 30 - 35 days after planting and the second dose, a fortnight later.
- In order to minimize losses from seed borne diseases treat the seed prior to seeding with the recommended seed protectant viz., thiram / captan at the rate of 2.5 g / kg of seed.
- Wherever downy mildew is endemic use metalaxyl @ 6 g / kg of seed in place of thiram / captan
- .Dibble the seed at the stipulated intra and inter row spacings.
- Unless the quality of seed is exceptionally good and seed bed conditions optimal, plant 2-3 seeds / hill and then thin out all excess seedlings to maintain one healthy seedling / hill positively within 10 - 15 days after germination.
- Avoid placement of seed deeper than 5cm from the soil surface as it affects emergence and stand establishment.
- Normally freshly harvested sunflower seeds have a dormancy period of 45-50 days.
- The seeds will be ready for sowing after the expiry of this dormancy period.
- Although not feasible on commercial scale, the problem can be over come by treating the seed with ethrel solution (25ppm) equivalent to 40% by volume of seeds.
- Seeds can be soaked for a period of 6 hours and then dried in shade before sowing or can be sown directly.
- The best season for production of quality seed is rabi / summer in the conventional sunflower best and or spring in the Northern parts of the country.
- Optimum time of planting recommended for taking up seed production programmes in different season are as under:
|Conventional sunflower growing areas||Kharif||June-July:December - January|
|Nonconventional (Northern parts of the country)||Spring||Second fortnight of January to end of February|
|Spacing and seeding rates||Row to row Plant to plant within the row||60cm 30cm|
|Seed rate Parental lines||Female, Male||4 kg / ha|
|A line (female parent) production||1.25 kg / ha|
|R line (male parent)production||5 kg / ha|
|Open pollinated population/ varieties||5 kg / ha|
|Hybrid seed production||
Female (A line)
4 kg / ha
1.25 kg / ha
Spatial arrangement of male and female lines
- For both A line as well as hybrid seed production plots, plant one row of male after every 3 rows of female lines.
- In order to ensure adequate supply of pollen to female lines plant the first and last two rows of seed production plots with male lines.
- Alternatively, planting female and male lines in separate blocks in 3:1 proportion in the same seed production plots will help in avoiding mixtures in the hybrid seed.
- Sunflower is highly cross pollinated crop.
- Hence, maintenance of prescribed isolation from other sunflower varieties / hybrids for avoiding any possible contamination is one of the most important and basic requirements for any sound seed production programme.
- Ensure a minimum isolation distance of 1.5km in case of breeder and foundation seed production and 1.2km in case of certified seed production plots.
- This isolation distance suggested for breeder, foundation and certified seed production plots are much higher than those currently prescribed under seed certification (=600mts).
- Considering the role of honey bees in pollination, their flight range, problems encountered so far in maintaining the genetic identity and purity of parental stocks of commercial hybrids and the standards prevailing in other important sunflower growing countries of the world, the above isolation distances are, however, essential.
- Sunflower Management