Sunflower is a cross pollinated crop ,honey bees are pollinating agents.
The crop has got 2 types of flowers,ray and disc florets of seed set in disc florets which are bisexual but exhibit self incompatibility due to protoandrous nature of the flower.
Flower opening starts from outer whorl and proceed towards center of head .the head bloom within 5-10 days .The pollen grains are viable for 12 hours .Anthesis takes place at 5-8 am
In hybrid sunflower are produced by CGMS
Seeds are produced by transferring the pollen of male parent to female parent with the help of honey bees at 5hive/ha
Male and female parents are raised in 1:4 ratio under 400m isolation distance
Supplementary pollination:As in hybrids the pollen should be collected from the male parent first then the collected pollen should be transferred to female parents by using with the help of brush.
Principle of hybrid seed production:
Hybrid sunflower is produced by using cytoplasmic male sterility and genetic fertility restoration system
The male sterile line contains sterile cytoplasm and recessive gene for fertility restoration
This is maintained by a male fertile counter part which also contains recessive genes,but has fertile cytoplasm
For production of hybrid seed male sterile line is crossed with a fertility restoring line which has the dominant gene for fertility restoration,but may have either sterile or fertile cytoplasm.
The restorer line should Nick well with the A line to produce F1 hybrid seed
Season – October to November
Isolation distance -FS -600m,
CS- 400m
Seeds and sowing –
Seeds should be sown in ridges and furrows.
Male seeds should be sown one week before sowing of female seeds
Spacing- 60×30cm
Major pest – Grass hopper,cut worm, hawkmoth caterpillar
Major disease- Bud necrosis, Root rot
Management – chloropyriphos 20EC @2ml
Roughing:The male fertile parent in the female parent lines should be removed each day during the entire flowering period .This is best done in the morning hours before the bees have removed the pollen.Roughing for off types should be done in the similar manner as described for open pollinated varieties.
Harvesting: The male parent rows should be harvested prior to harvest of female rows to avoid contamination.No male parent heads should not be left with the female parent rows .other aspects of harvesting are as similar as described earlier for open pollinated varieties.
