Method of Seed Production

Method of Seed Production
    Seed production
    • The seed production is taken in the hills for European types and in the plains for Asiatic types.
    • European types require high chilling of 4 7° C for a period of about 2 months.
    • The summer and low rainfall of hills especially during flowering and seed setting stages are beneficial.
    Method of seed production
    • 1. Seed to seed (In situ method),
    • 2. Root to seed (Transplanting of cut root)
    • Stages of seed production Breeder seed→ Foundation seed →Certified seed
    Varieties
    • Ooty 1, Pusa kesar, Zeno, Panvers, American beauty, Imperator
    Hybrids
    • Pusa hybrid 1
    Season
    • The ideal season for sowing to take up seed production is July August
    Land requirement
    • There are no specific requirements, but the land should be free of volunteer plants.
    Isolation requirement
    • The minimum isolation distance required for carrot seed production is at least 1000 m for foundation and 800 m for certified seed production.
    • Because of the high possibility of cross pollination, isolation distances for commercial seed crops should be 1000 m. For nucleus seed the distance should be at least 1600 m.
    • In areas that specialize in carrot seed production the different cultivars within the same type can be zoned; this minimizes cross pollination between the different types.
    • Cultivated carrots cross pollinate very readily with the wild carrot and this must be taken into account when choosing sites for seed production.
    • Contamination of seed crops by wild carrot pollen is a major reason for genetic deterioration of seed stocks in some areas.
    Seed production methods
    • There are two methods of seed production.
    Seed to seed method
    • The crop is sown as per climatic conditions of the area. For temperate varieties in Himachal Pradesh sowing is done in the month of October and November. Crop is left in the field for flowering and seedling. The roots cannot be inspected (or) rogued.
    Seed rate
    • 2 3 kg/ha. Row spacing of 50 90 cm are used with a sowing rate of 2 3 kg per hectare. Soaking seeds in water for 72 h with a change of water every 24 h leached off the inhibitors will improve germination.
    Root to seed method
    • This system is similar to raising carrot crop for fresh roots as far as timings are concerned but the plants (steckling) are raised in beds and transplanted in the spring. Depending on local customs and winter conditions and stecklings are either left in situ during winter or lifted in the late autumn and stored until replanting in the spring.
    • The transplanted steckling rows are 75 cm apart with 30 cm between plants. The seed rate is 6 8 kg ha. Raising stecklings that are later transplanted from their beds offer the opportunity for roguing plants with undesirable root or foliage characters while lifting and planting.
    Roguing
    Minimum of 3 field inspections should be done at 20 30 days after sowing, when roots are lifted and replanted and flowering stages. Roguing should be done based on the root colour, shape, skin colour, flesh colour of the root and bolting characters and removed.
    Field standards
    Contaminants Minimum distance (meters)
    Mother root production stage foundation certified Seed production stage Foundation certified
    Field of other varieties 5 5 1000 800
    Fields of the same variety not conforming to vareital purity requirements for certification 5 5 1000 800


    Seed to seed production
    • Very little if any roguing can be done when the crop is grown on without lifting. But plants bolting early and those with a typical foliage characters should be removed. If the crop is lifted and replanted it is rogued as described below for root to seed, but very little confirmation of root type can be done.
    Root to seed production
    • During the first year growing season. a) Remove plants displaying typical foliage, remove plants bolting in the root development stage. b) After the roots have been lifted inspect for trueness to type, according to root shape, colour and size, discard roots showing poor colour, green shoulder, incorrect colour, off coloured shoulders (purple, green), split or fanged roots or those with rough surfaces.
    Hybrid seed production in carrot
    • The production of hybrid seed by hand emasculation and pollination is not possible commercially as the flowers are very small and single pollination gives only one or two seeds. In carrot, the inflorescence is compound umbel.
    • Sufficient buds in the female parent at peak stage of flowering are emasculated and the remaining young ones are removed. Then a cloth / paper bag is placed over the umbel of male parent and shaken to dislodge the pollen onto the sides of the bag. This bag is then used to enclose the emasculated umbel of the female parent. Apart from this, daily for a few days in the morning, the male umbel is gently rubbed over the female to ensure cross pollination. Sometimes when the pollen parent possesses some dominant marker gene with the help of which the hybrids can be distinguished in the seedling stage, it is not necessary to emasculate the flowers.
    Hybrid seed production
    • In the heterosis breeding programme 3 lines are used, namely the male sterile line (A), male fertile sister line (B) and the pollinator line (C) that is male fertile has a good combining ability with the male sterile line. The male sterile and pollinator lines are grown in alternate rows of 4:1 or 8:2 and the hybrid seed is harvested from female line only.
    Manuring
    • First season: A light does of 20 25 tons of FYM per ha should be applied before field preparation.
    • Nitrogen 75 kg/ha (35 kg basal + 35 kg top dressing)
    • Phosphorus 50 kg/ha (basal)
    • Potash 50 kg/ha (basal)
    • Second season (During transplanting)
    • Farm yard manure 10 to 15 tons /ha
    • Nitrogen 50 kg (25 kg at pre bolting + 25 kg before flowering)
    • Phosphorus 50 kg (basal)
    Supplementary pollination
    • Since the honey bees are important pollinating agents. It is advisable to place beehives in the large seed fields or near by the field to increase the pollination. It is necessary when the temperature is below 15°C. Spraying of 150 ppm NAA at bolting stage also improved the seed setting percentage.
    Pest and disease management
    • The major pests in carrot are Carrot Weevil, Spotted leaf hopper and rust fly. These can be controlled by spraying Malathion 5% dust or Carbaril @ 5 kg/ha.
    Nematode
    • Application of neem cake @ 1 ton/ha at planting to control root knot nematode, Meloidogyne spp.
    Diseases
    Leaf spot
    • Spraying of Mancozeb at 2 g/lit.
    Harvesting and processing
    • The crop matures unevenly. Seeds are harvested when the secondary umbels (heads) are fully matured (brown) and the tertiary umbels are beginning to turn brown. Hence 2 to 3 picking may often be necessary. After drying seed heads are threshed, cleaned and rubbed by hand to remove the bristles. The seeds are dried to 8% moisture content and treated with Bavistin @ 2 g per kg of seed.
    • Size grading of seeds with BSS 12 wire mesh sieve or density grading at 0.5 inches of water pressure found to be optimum to upgrade carrot seeds.
    Removal of bristles in carrot seed
    Figure 2. Removal of bristles in carrot seed
    Seed standards: (Variety & Hybrid)
    Factors Foundation Certified
    Pure seed (minimum) 95% 95%
    Inert matter (maximum) 5% 5%
    Other crop seed (maximum) (no./kg) 5/kg 10/kg
    Total weed seed (maximum) (no./kg) 5/kg 10/kg
    Germination(minimum) 60% 60%
    Moisture (maximum) (normal container) 8% 8%
    For VP Container(maximum) 7% 7%

Last modified: Monday, 25 June 2012, 6:36 AM