Propagation through seeds:
Propagation through seeds is one of the cheapest and easiest methods.
Som being a cross pollinated plant, sexual propagation introduces variability in the progeny and gives scope for selection of new varieties. It is suitable for large scale multiplication to build up stocks for preparation of grafts.
Comparatively long gestation period to provide leaves for silkworm rearing. The desirable traits of improved cultivars cannot be perpetuated.
Source and time of collection of seeds
Seeds of Som become mature in April to June in Assam and other N.E. states. Collect mature seeds from the plants during April and May in lower Assam and May and June in upper Assam and other N.E. states.
Viability of Som seed: There is no dormancy in Som seeds. Freshly harvested seeds have highest germinability. Seed is viable up to 10-20 days after harvesting of seed. The lose viability with the passage of time. The viability of Som seeds loses if preserved for a long period. Viability decreases after 20 days of storage till 45 days.
Selection of viable seeds: The seed quality can be selected by floatation test. Selection of healthy and viable seeds is done by floating the seeds in water. The healthy seeds sink and shriveled and unfertilized seeds float. The pulp of the seeds is washed off by kneading two or three times in running water and dried under shade for a few hours.
Storage of seed: The seeds may, however, be stored in moist seed beds for six to eight weeks under low temperature to prolong their viability. 10°C is the storage temperature of Som seed. It is desirable to predict the quality of the seeds in respect of germination capacity.
Raising of Som seedlings: Som seedlings can be raised by sowing seed in soil directly or in polytubes.
Pre treatment of seeds and Seed dressing:
Preparation of nursery Bed or Seed bed: Nursery can be prepared after monsoon from mature seed. Seedlings are available in plenty in a plantation before monsoon. Though seeds can be directly used for raising plantation, the present trend is it grow seedlings in the nursery and transplant them in the field to reduce the period of establishment and save wastage of precious seed material.
Layout of bed / Bed size
Seed sowing: Seeds are sown in lines in the prepared beds at a spacing of 15 cm in the row and 15 cm between rows at a depth of about 2-4 cm. Sow 2 kg seeds (approx.)/bed
Germination of Seed:Germination starts after 30-45 days of sowing. Germination of Som is 82% (average). Normally one seed gives rise to one seedling only but polyembryonate seedlings are also known to occur. In the polyembryonate seedlings, twins and triplets have been observed in Som which are rare occurrences. The frequencies of twins and triplets are 4.5% and 0.6% respectively. The twins and triplets after separation are capable of developing into independent plants.
Transplantation of seedlings to poly tubes:
Gap filling: Gap fills on the 10th day of sowing of seed on seed bed. Gap filling of seedling polytubes