Seed Production- Flowers
The production of propagating material like seeds, bulbs, live plants is being done conventionally and these materials are being sold. Successful nurserymen are making handsome money. There are a few nurseries reputed for true-to-type and reliable plant material.
In case of Orchids Seeds are non-endospermic or endospermic or endosperm nucleus and are produced in large numbers extremely light and with undifferentiated embryo. As many as 40,00,000 seeds/capsule are produced. The seeds are dispersed by wind. The orchid seeds being non-endospermic in nature cannot utilize their own reserves and hydrolyse larger molecules of starch or cellulose. Hence, under natural conditions seeds germinate after being affected by a fungus- the orchid mycorrhizia which supplies sugar to germinating seeds or orchids. As a result asymbiotic germination in the absence of sugar proceeds only upto the early protocorm stage.
Seeds from green pods are sown on the autoclaved media under aseptic conditions. After 15-20 days, the embryo start swelling and after 30-35 days, 2 leaf stage is achieved. At 4-leaf stage the seedlings are taken out from flasks and after thorough washing and are planted in community pots in 1:1 mixture of shredded tree fern fibre and charcoal.
Under north India conditions in the plains the best flowering has been observed during winter months i.e. from October to April. Land should be well prepared by ploughing it 2-3 times and 50 tons of well rotten farmyard manure should be well mixed/ha.
There are two common methods of propagation of marigold i.e. (I) by seeds; (ii) by cuttings. Crop raised from seeds is tall, vigorous and heavy bloomer; thus, it is preferred over cuttings.
Seeds of wide range of varieties of common species i.e. T. erecta, T.patula and T. tenuifolia are easily available and germinate quickly. Propagation through seed is advised. For better seed germination, optimum temperature range is between 18 to 300 C. for raising seedlings for one hectare, about 1.5 kg. Seed is required. Nursery beds of 3X1 m size are thoroughly prepared and mixed with 10 kg of well rotten farmyard manure per sq. m About 8 to 10 such beds are needed to raise seedlings for one hectare. Seeds can be sown preferably in lines or by broadcast method. In case of broadcasting care should be taken for proper distribution of seeds so as to have healthy seedlings. For this, thinning is an important operation in both the methods. Seeds need to be covered with light soil or sand or strained leaf mould and watering should be with rose can. For entire period, nursery should be kept moist but not wet and thus watered accordingly.
In case of Dahlia only dwarf bedding singles are usually grown from seeds. Plants of large flowering types raised from seeds show a heterogeneous mixture. From a strain of double, there will be a large portion of single and semi-double flowers, also greatly varying in height and colour. It is interesting to grow and test out seedlings from good varieties with the hope that new and better variety may result.
Sow the seeds thinly in shallow boxes or seed-pans containing porous soil, cover it with a layer of screened leaf mould and water through a find rose. Under tropical condition, sowing should be done in September-October and the seedlings will be ready for transplanting in three to four weeks.