Introduction The hybrid seeds are produced bycrossing female and male lines and harvestingthe seeds from female line. Maize hybrid seedproduction there is no male sterility system infemale plants.
Suitable climate• In Tamil Nadu, maize is cultivated during June – July, September – October and January – February seasons.• Sowing during November - December is suitable for seed production, since seed maturity stage will not coincide with rainfall.
Isolation distance• For this isolate the hybrid seed crop from fields of other maize varieties with same seed color by 200 m distance.
Land requirement• Well drained sandy red or black soil is suitable.• The selected fields should be free from volunteer maize plants.
Field preparation….• Plough the field five to six times to get fine tilt.• Spread 12.5 tons of FYM or composted coir pith and 10 packets of Azospirillum in the field.• Prepare ridges and furrows with 60 cm spacing.
Sowing operation• Seed rate Female -5kg/ha Male-2 kg/ha• Treat the seeds with Azospirillum.
Seed treatment• To control the fungal disease treat the seed with thiram at 2g kg-1 seed.• One day after treat the seeds with 600 g of Azospirillum with rice gruel and shade dry for 15 minutes.
Sowing• Ridges and furrows at 60 cm spacing is to be formed.• 2 seeds per hill on the sides of ridges adopting a spacing of 25 cm between the plant is sown.• During sowing, a planting ratio of 4 female lines and 2 male lines (4:2) should be followed. Four female line rows should alternate with two male rows.
Irrigation• Up to 30 days, less irrigation is given.• Then it is necessary to irrigate once in 10 days.• Smooth silk will emerge out from the cob after fertilization.
Fertilizer application• Apply 25 tonnes of FYM per ha.• Then apply inorganic fertilizers at 100 kg N, 100 kg P and 50 kg K per ha as basal dose.• On 20th and 40th day after sowing, apply 50 kg N and 25 kg P as top dressing.
Micronutrient deficiency• Zn and Mg deficiency occurs - leaves.• Apply ZnSO4 @ 20 kg ha-1 as basal fertilizer.• Apply micronutrient mixture @ 62.5 ha-1 mixed with 40 kg sand, after sowing the seeds.
Weed management• Two hand weeding on 25 days and 45 days after sowing.• After weeding, apply fertilizers as top dressing and do the earthing up operation.• Herbicides can also be applied. Spraying of Atrazin 500 g mixed in 1000 lit water and life irrigation on third day control the weeds.• Roguing
PLANT PROTECTIONINSECT CONTROL DISEASE CONTROL
Insect ControlShoot fly - 2ml of endosulphan in 1l ofH2O.Stem Borer - carbofuran granules @ 7.5kg per acre @ 2 granules per plant
Cob – female inflorescence Tassel – male inflorescence
DETASSELLINGRemoval of tassels from female plants immediately afteremergence
HARVEST• Judge the optimum harvest stage• Male lines – Harvested first• Female lines – Next• Hybrid seed – seeds from the female line.
COB SORTING• To maintain genetic purity• Remove very small sized seeds• Cobs – Difference in seed rows, seed number and colour.• Cobs – very less seeds
SHELLING• Separation of seeds from the cob• Moisture content * seed – 15% * cob – 25%• Mechanical damage – 18%
SEED DRYING• Reducing the moisture content• To retain their viability• Moisture content – 7%• Temperature – 40 C• Avoid - Drying under hot sun
SEED GRADING• To maintain the quality from one season to the next * Other crop seeds * Weed seeds (especially herbicide resistant weeds) * Straw, soil dust and other inert material. * Immature, shriveled, damaged, cracked, under sized or oversized seed• Yield = 1500 Kg /ha
SEED STORAGE• Captan 75%• Wettable powder @ 70 g per 100 kg seeds mixed in 500 ml water.• Package - Cloth bag or Vapour proof polyethylene bag.• Storage – 1 to 1 ½ years.
SEED CERTIFICATION• Genetic purity: Seed gives rise to a plant of the same varietal characteristics• Physical purity: Seed Is free from stones, broken seeds, straw bits and leaf bits etc.,• Physiological purity: Germination and vigour
Contd.,• Authenticated source• Isolation distance• Inspection• Seed samples• Certification tag - Blue
FIELD STANDARDS FACTOR MAXIMUM PERMITTED (%)Off types (%) maximum 0.5%Shedding tassel (%) maximum 1.0%