Seed Production

SEED PRODUCTION

SEED PRODUCTION
Land requirements
  • Land to be used for seed production of Brussel’s sprouts should be free from volunteer plants.
Climatic Requirements
  • Brussel’s sprout thrives best in a relatively cool, moist climate with moderate rainfall, well distributed during the growing season.
  • It can withstand frost in the head stage.
  • It requires a dormant period of cool temperature for initiation of seed stalks and flowers.
  • Cool temperature, however, is effective only after stem has attained at least 1cm diameter. In temperate climates, this occurs during the winter after the first season growth.
  • Flowering and seed production follow in the second year.
  • Headed plants form seed stalks when exposed to mean temperature of about 2.22oC to 10oC for 42-56days to eight week.
  • In India, seed production of Brussel’s Sprout is possible only in hilly areas.
Isolation Distance
  • Foundation seed :1600m
  • Certified seed :1000m
Methods of Seed Production
  • Being a biennial, Brussel’s sprouts require two seasons to produce seed.
  • In the first season, the heads are produced and in the following season seed production follows.
  • The seed crop can be left in-situ or replanted during autumn.
  • In-situ method is usually followed for certified seed and the latter for nucleus seed production.
  • In In-situ method, the crop is allowed to over winter and produce seed in their original position i.e. where they are first planted in the seedling stage.
  • In the transplanting method, the mature plants are uprooted.
  • After uprooting, the plants are immediately reset in a well prepared new field.
Methods to produce seeds of Brussel’s sprouts:
  • Seed production of Brussel’s sprout is same as that of cabbage except that in-situ (seed-to-seed) method is followed since the plant does not withstand planting.
  • However the plant with earthen ball may withstand planting well.
  • After transplanting, the crop is allowed to over winter in the field.
  • Flowering and seed- setting take place in spring-summer (from mid march to mid may).
  • The plants after receiving the vernalization stimulus bolt and flower in the spring when the temperature rises.
  • The flower stalk arises from the terminal growing point and also from some of the upper sprouts.
  • First the main flowering stalk with branches develops from the terminal bud and the other flowering branches come from the axillary buds i.e. sprouts.
  • Therefore, do not harvest the upper sprouts to allow more number of flowering branches. Flowering takes place from April to May.
  • The ways and means to enhance seed set are similar to those followed for other crops.
Roguing
  • The first roguing is done at the time of handling of mature crop.
  • All off type plants, diseased, or otherwise undesirable types are removed at this stage.
  • The second roguing is done before the heads start bursting.
  • The loose leaves, poorly heading plants and those having a long stem with heavy frame must be rogued out at this stage.
  • It is highly undesirable to keep such poor plants in the seed plots.
  • Subsequent roguing for off-types, diseased plants, plants affected by phyllody, black leg, soft rot or leaf spots should be done from time to time as required.
Brief Cultural Practices (In-situ method)
Time of Sowing and Transplanting
  • The sowing time of different varieties should be so adjusted as to complete head formation by the end of October or first week of November, when the mean temperature falls to 10oC or below, at this temperature, the heads stand best for over wintering.
  • Early varieties should be sown from mid July onwards and transplanted when the seedlings are four to six weeks old, during the second fortnight of August.
  • This sowing time must be strictly adhered to, as the crop from early sowing has matured heads during September (20oC).
  • The heads sometimes get infected with bacterial stalk rot, which is very severe.
  • The late crop, planted during September does not form heads and bolts directly during spring and the seed grower is not able to ascertain purity of the crop.
  • The mean temperature of 22.5oC, 20oC and 14oC of August, September and October, respectively afford optimum requirements for growth and head formation.
  • The late transplanted crop starts head formation during spring and continues up to June and usually does not produce seed stalks.
Preparation of land for transplanting
  • Prepare the land to a fine tilth by repeated ploughing and harrowing followed by levelling.
Source of seed and seed rate
  • Obtain nucleus/breeder/foundation seed from source approved by a seed certification agency.
  • For main season and late varieties take 375-400g seed/ha and for early varieties, 600-750g seed/ha.
Method of raising nursery
  • The seeds are sown in raised nursery beds in a similar manner as described earlier in commercial production of Brusse'ls sprouts.
Transplanting
  • Four to six weeks old seedlings are transplanted.
  • Transplanting should preferably be done in the evening and the field irrigated immediately afterwards.
Spacing
Nutrient management
  • Brussel’s sprouts grow satisfactorily only when the supply of organic matter is liberal.
  • For good crop, apply 20 to 25tonnes of farmyard manure per hectare at the time of land preparation.
  • Apply half dose nitrogen (50 kg/ha), 200kg/ha phosphorous and 100kg/ha of potash by drilling, or by broadcasting, sufficiently before transplanting the seedlings.
  • Give another dose of 50kg/ha nitrogen as surface application at the time of seed stalk emergence during April.
  • Extra application of nitrogen may be given as and when there is a need before flowering starts, depending upon the condition of the crop.
Irrigation
  • Brussels’s sprout requires a regular supply of moisture.
  • Irrigate the crop as frequently as required.
  • Heavy irrigation should, however be avoided when the heads have formed.
  • A sudden heavy irrigation after a dry spell may cause bursting of head.
Hoeing and weeding
  • At least three weddings and hoeings till the end of October are essential.
  • One weeding and earthing up during November-December and the second during March when seed stalks have emerged, control weeds and also help in proper drainage during winter and thereafter.
Staking
  • After the flower stalks are sufficiently developed, staking is necessary to keep the plants in an upright position.
Handling the mature head
  • After the planted crop has fully developed, crop with good heads is selected at the end of autumn and these plants are marked for seed production.
  • Handling of plants can also be done carefully so that good and true to type plants are selected for seed production.
Harvesting and threshing
  • Brussels sprout starts seed stalk elongation by the end of March when the mean temperature rises to 10-13oC.
  • Flowering and pod formation starts during the last week of April at mean temperature of 13-18oC.
  • By last week of May, the crop is in full flush of flowering and fruiting.
  • The ripening of pod commences at the temperatures below 20oC during June and July, the maturity of crop is delayed at least by a fortnight and the harvesting may continue up to July end.
  • To avoid shattering of seeds, the whole crop is harvested in two or three lots with sickles.
  • Generally, the plants are harvested first by hand when the pod colour is brown and about 60-70per cent of the rest of the crop changes to yellowish brown, it is harvested completely and piled up for curing.
  • After 4-5 days of curing, is then threshed with sticks and sifted with hand sifters.
  • After thoroughly drying seeds are cleaned and stored.
SEED YIELD
  • 300-400kg per hectare.
SEED CERTIFICATION STANDARDS
Field Inspection
  • A minimum of three inspections should be done first before the marketable stage, the second at the marketable stage and the third at flowering stage.
A. Field standards
a. General requirements
Isolation distance
  • Seed fields should be isolated from the contaminants as shown in the table:
Contaminants
Minimum distance(meters)
Foundation Seed Certified Seed
Fields of other varieties 1600 1000
Fields of the same varieties not conforming to varietal purity 1600 1000

b. Specific requirements

Factors
Maximum Permitted (percent)
Foundation Seed Certified Seed
Off types 0.10 0.20
Plants affected by seed Borne diseases ( Black leg, Black rot, soft rot) 0.10
0.50

B. Seed standards

Factors

Standards for each class
Foundation Seed Certified Seed
Pure seed (Minimum ) % 98
98
Inert matter (maximum ) % 2
2
Other crop seed (maximum in ) number/kg 5
5
Weed seeds (maximum ) number/kg 5
5
Germination (minimum) %
65
65
Moisture (Maximum ) % 7
7
For vapour proof containers (Maximum %) 5
5



Last modified: Thursday, 21 June 2012, 5:38 AM