Seed Production of Vegetable, Tuber and Spice Crops

Hybrid seed production

Hybrid seed production

• The planting ratio of female and male parents adopted for hybrid seed production is normally 5:1 or 6:1.For production of hybrid seeds, crossing programme is done using emasculation and dusting methods as followed in tomato.
Emasculation and pollination

• Emasculation is done in the afternoon hours. Of the four types of flowers, only the flower buds having long or medium style are emasculated. In brinjal, flowers appear both as solitary or in cluster, in the noncluster fruited cultivars, generally single flower in a cluster of 3-5 is long or medium styled. After selecting the long or medium styled buds, the corolla is opened gently from the side, length of the style is glanced and then the anthers are picked off separately by upward pull with the forceps. The emasculated flowers are protected by thin cotton wool.
• Using a needle, the anther cone is carefully removed without disturbing the style. These emasculated flowers have to be covered by butter paper bags. Similarly the flowers of male parent from which pollen is going to be collected have to be bagged on the previous day evening. Next day morning by 6 am the flower buds are collected before opening. Anthers are separated and kept in petridish covered by glass. These petridishes are kept against sunlight to facilitate dehiscence of anthers and release of pollen grains. The butter paper cover on the emasculated flower is removed and the pollen is transferred to the stigmatic surface with the help of a camel hair brush or by smearing the dehisced anther on the stigma. A part of sepals of the pollinated flowers are cut with the help of a scissors for identification mark that they are hybridized flowers. After hand pollination these flowers are rebagged. Since the stigma is receptive for 4 days, the bags should be removed after about 8-10 days only when the fertilized ovary will prominently seen. After full maturity and ripening of the fruits, seeds are extracted. On an average a quantity of 400 kg of hybrid seeds can be obtained from one hectare.
Male sterile lines

• Use of male sterile lines reduces the cost of seed production. In brinjal functional male sterile mutants was also reported. This is at a recessive character determined by single gene. It is therefore, easy to transfer this character into desirable standard varieties to be used as female parent for hybrid seed production.
Harvesting and processing

• Harvesting is done when fruits are fully ripe (when the fruits turn into yellow colour) i.e., 45 days after flowering. The harvested fruits are to be graded for true to type and off type and fruit borer infested fruits are discarded. The graded fruits are cut in 2 3 pieces or whole fruits will be put in a cement tank with water and crushed manually and then allow it for fermentation for 1 2 days. Then the floating pulp portions are to be removed, the seeds settled at the bottom should be collected and washed with water and then the seeds are treated with commercial Hydrochloric acid @ 3 5 ml/kg of seed. The mixture is kept for 10 15 minutes with frequent stirring. Then the treated seeds are to be washed with water for 3 4 times. Afterwards seeds are dried under shade for 2 3 days over a tarpaulin and followed by sun drying for 1 2 days to reduce the seed moisture content to 8 per cent. Then the seeds are cleaned and graded with BSS 12 sieve. The processed seeds are treated with fungicides or Halogen mixture @ 5g/kg of seed.
• To upgrade the seed lot water floatation technique and specific gravity grading are commonly used. Seeds can be stored in aluminium foil pouches by which the viability can be maintained upto 18 months under ambient condition, by dressing the seeds with 2 g of thiram / kg of seed.


Optimum stage of harvest

Seed treatment

• Seeds must be treated with fungicides before storage. The seeds may be treated with Captan or Thiram @ 4g/kg of seeds. The seeds can also be treated with halogen mixture @ 5g/kg of seed and it is an ecofriendly seed treatment.
Storage containers

• Seeds could absorb moisture from atmosphere. Hence storing seeds in the coastal region (or) river sides we should use moisture vapour proof containers i.e. 700 gauge polyethylene bags. For seed storage every time new containers must be used.
Seed Yield

• 100-200 Kg/ha
Seed Standards (Variety & Hybrid)

Factors	Foundation & Certified
Pure seed (mini)	98%
Inert matter (maxi)	2%
Other crop seeds (maxi) no/kg	None
Weed seeds (maxi)	None
Germination (mini)	70%
Moisture (maxi)	8%
For VP container (maxi)	6%
Genetic purity required for tomato & brinjal hybrids	90%