Method of Seed Production

Method of Seed Production

    Seed production
    • As with other biennial root crops, both seed-to-seed and root-to-seed methods can be followed in producing beet seed. Since the interior flesh colour is important, the root-to-seed method is followed greatly. The seed-to-seed method has certain limitations for its use as described under other root crops.
    Seed-to-seed method
    • This method is also known as in-situ or over-wintering method. It is much simpler than root-to-seed method because the roots are allowed to over-winter in the field where they were grown earlier and thus time and cost of labour is saved. The only drawback is the lack of thorough roguing. The stock seed used for seed-to-seed plantings should be taken from a crop which represents trueness-to-type and freedom from rogues of all kinds. The use of this method should be restricted to the production of only certified seed (market seed) as on the grower’s field negligible off-types do not matter much.
    Root-to-seed method
    • This is the specialized technique of quality seed production where the roots / stecklings of beet are grown first year in the same way as for market crop and in second year the selected roots are replanted in the well prepared field for the seed crop. This is the most satisfactory method of stock seed production and also followed in breeders’ seed and foundation seed production.
    • When the roots reach full size by the end of the growing season, they are either replanted immediately or stored in trenches depending upon the severity of winter (amount of snowfall). In areas of heavy snowfall like Kalpa (Himachal Pradesh), stecklings uprooted in November-December are stored in shallow trenches up to March by the time snow melts. The stecklings receive the necessary chilling during their storage in the trenches.
    • The stecklings should be larger in size as smaller ones get shriveled and dried in the storage. The depth of the trench should not be more than 45-60 cm otherwise the stecklings in the lower layer of storage pit get overheated and will be devoid of adequate thermal induction although they are well protected from freezing.
    • In Kullu and Srinagar, where the snowfall is light the roots are planted immediately after lifting. The merits and demerits of this method remain the same as with other root crops.
    Land preparation
    • The soil should be thoroughly prepared by ploughing the land about 4-5 weeks before sowing. Ploughing in June in temperate region before the rainy season starts, helps to take care of weeds and ease the preparation of field in July / August when rains actually start.
    Manures and fertilizers
    • Apply well rotten farmyard manure 10-15 tones / ha at least 4-6 weeks before sowing the seed. At the field preparation, 50 kg N, 50 kg P2O5 and 100 kg K2O should be incorporated thoroughly into the soil in the ratio of 1:1:2. Another dose of N 50 kg / ha is applied before initiation of root development. If the seed is to be produced by in situ method apply 10 tonnes farmyard manure, 50 kg P2O5 and 50 kg K2O at the field preparation.
    • Apply about 100 kg N in 2 equal split doses, first after 40 days when the new leaves start developing and the second at bolting of the crop. In the crop raised for steckling production, borax @ 20-25 kg/ha is helpful to prevent canker and internal breakdown as black spot or dry rot and the development of good quality roots.
    • In poor growth, 4-5 weekly sprays of 1-2% urea in the replanted crops are helpful to push up the growth.
    Spacing
    • For beet seed production, moderate-sized stecklings having a diameter of 5-7 cm are more preferable to either smaller or larger ones.
    • For raising of stecklings, 45 cm x 10 cm and for replanting stecklings 45 cm x 45 cm of 60 cm x 45 cm spacings are most suited.
    Seed rate
    • For in-situ method of seed production, seed rate of 5-6 kg/ha is sufficient. For raising stecklings, seed rate of 10-12 kg / ha is used and this will provide sufficient stecklings under better management to replant 7-8 ha of seed crop.
    Sowing time and replanting
    • The optimum time for sowing is the second fortnight to July in Kullu and Srinagar where the snowfall is comparatively low and root-to-seed or in situ method is followed.
    • Time of sowing influences size, shape and colour of foliage, and texture. The root develops good colour, texture and quality under cool weather conditions.
    • Under high warm weather, zoning is caused which is marked by the appearance of alternating light and dark red concentric circles in the root.
    • Roots developed at a relatively high temperature had poor colour and the roots become coarse with woody flesh, while those planted in cooler months had excellent colour and quality.
    • Hence, early sowings should be discouraged for seed crop.
    • ransplanting of mature best stecklings like other root crops, should be done in November or early December after which the temperature drops considerably.
    • Late planting results in the development of small seed-stalks with less number of branches and flowers.
    Bolting, flowering and seed-setting
    • Beet has only temperate types which bolt and produce seed only in response to low temperature. Sometimes premature bolting is there in the crop grown for stecklings. There can be two causes responsible for it: (a) seed produced in areas having long winters and short summer with good rainfall get vernalized during later stages of ripening. The stecklings raised from this seed go to bolting before attaining maturity: (b) if the temperature goes low (4.40 – 100C) for 15 days or more in the early stages of crop growth, some percentage of bolting is likely to occur in the field. This is particularly true in the case of the crop grown later in the season (October-November) in the plains of North India, which is vernalized during winter before reaching maturity.
    • Transformation from vegetative to reproductive phase takes place only when the plants after root formation are exposed to low temperature of 4.40 – 100C for 60-90 days, depending on the variety. Crop is allowed to over winter either in the field or in the trenches depending on the extent of snowfall. At lower temperatures induction period is reduced to some extent. Unless the chilling requirement is complete, a rise in temperature beyond 210C nullifies the effect of earlier cold period and causes reversion of reproductive processes to the vegetative phase. This is called devernalization. As this reversion is irreversible, such plants cannot be vernalized again and remain in the vegetative stage. Plants are conditioned for production of flower-stalks by low temperature treatment but the elongation of seed-stalks actually takes place under long photoperiods.
    Plant protection
    Pests
    • Leaf miner and flea beetle
    • Spray malathion 50 EC 2 ml/lit.
    Diseases
    Cercospora leaf spot
    • Spray Mancozeb at 2 g/lit.
    Rhizoctonia root rot
    • Spot drenching with Carbendazim at 1 g/lit.
    Harvesting
    • Ripened seeds sometimes shatter easily but if harvesting is done early in the morning when it is sufficiently moist the problem of shattering can be prevented. As ripening is uneven, 2 to 3 harvestings manually are often necessary. To prevent losses in shattering, the seed crop should be harvested when two-thirds of the seed on a branch are being ripened i.e. changing in colour to light brown.
    Seed yield
    • On an average 800 – 1,000 kg / ha seed yield can be obtained.
    Field standards

    Factor

    Foundation

    Certified

    Off types 0.10% 0.20%
    Roots of other varieties not conforming to varietal characteristics 0.10% 0.20%

    Seed standards

    Factor Foundation Certified
    Pure seed (minimum) 96% 96%
    Inert matter (maximum) 4% 4%
    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) 9% 9%
    For VP Container(maximum) 8% 8%

Last modified: Monday, 25 June 2012, 6:37 AM