The institute conserves the genetic base of muga, eri and oak tasar sericulture — host plant morphotypes and plus-trees at the Conservation Centre at Chenijan, and twenty-six characterised eri eco-races at Lahdoigarh. This material is the raw stock for every breeding programme the institute runs, and for several it is the only surviving source.
Host plant germplasm — Conservation Centre, Chenijan
| Species | Morphotypes | Additional holdings |
|---|---|---|
| Som (Persea bombycina) | 14 | 182 plus-trees; 51 catalogued genotypes (PB001–PB051), of which four are tetraploids (PB009–PB012) |
| Soalu (Litsea monopetala) | 10 | — |
| Dighloti (Litsea salicifolia) | 10 | — |
| Mejankari (Litsea cubeba) | 4 | Host of the glossy white, highest-priced muga silk |
| Hybrids held | 18 | 14 S3 × S8 som hybrids and 4 dighloti × soalu hybrids |
Leaf yield across the eight isolated som morphotypes ranges from 2.55 to 3.60 kg per plant per harvest.
Selected som genotypes
| Selection | Genotype |
|---|---|
| Best polyploid | Gadadhar (PB012) |
| Best diploids | Naharpatia (PB003) and Kothalpatia (PB006) |
| Least susceptible to leaf spot | S3 |
| Released morphotypes | S-3 lanceolate and S-6 narrow ovate — 18–20 MT leaf/ha/year at 98.8 % palatability |
Muga silkworm biotypes
No ecorace is characterised in muga, unlike eri and tasar. What exists are morphotypes distinguished by larval, cocoon and moth colour, together with collected biotypes maintained off-site for hybridisation: Haflong green, a yellow mutant, Kokrapohia green and a wild hibernating type.
Wild stock outperforms cultivated stock on every measured character — about 300 eggs against 175, cocoon weight 4.5–8.55 g against 2.90–7.70 g, shell weight 0.60–0.96 g against 0.18–0.65 g. That gap is why the collected biotypes are held as breeding material rather than as a museum collection. Diapausing lines, which pupate November–March and emerge March–April, show higher cocoon and shell weight and are particularly useful in breeding. Full comparison on The Muga Silkworm.
Eri silkworm germplasm
Twenty-six eco-races of Samia ricini are characterised and conserved at CMER&TI, Jorhat, described against ten descriptors covering hatching, larval weight and duration, effective rate of rearing, fecundity, larval and cocoon colour, shell weight and shell percentage. Most produce white cocoons; Kokrajhar, Barpeta, Cachar and Rongpipi produce brick-red, and five further eco-races segregate for both. Six pure-line strains have been isolated on larval colour and marking — Yellow Plain, Yellow Spotted, Yellow Zebra, Greenish Blue Plain, Greenish Blue Spotted and Greenish Blue Zebra.
| Origin | Eco-races | Accessions |
|---|---|---|
| Assam | 18 | Borduar, Titabar, Khanapara, Dhanubhanga, Lahing, Barpathar, Diphu, Lakhimpur, Dhemaji, Kokrajhar, Cachar, Dhakuakhana, Jonai, Sadiya, Barpeta, Ambagaon, Rongpipi |
| Meghalaya | 5 | Nongpoh, Mendipathar, Adokgri, Genung, Tura |
| Nagaland | 2 | Chuchuyimlang, Dhansiripar |
| Manipur | 1 | Imphal |
| Arunachal Pradesh | 1 | Jona Kachari |
Full accession table, with larval strains and cocoon colour for each eco-race, on The Eri Silkworm.
Samia species of India
| Species | Status | Distribution |
|---|---|---|
| Samia ricini | Domesticated | Assam, Nagaland, Meghalaya, Manipur, Mizoram, Tripura, Arunachal Pradesh, West Bengal, Uttarakhand, Kerala, Maharashtra, Gujarat, Himachal Pradesh, Tamil Nadu, Andhra Pradesh |
| Samia canningi | Wild progenitor of S. ricini | North East, West Bengal, Uttarakhand, Kerala, Maharashtra, Himachal Pradesh, Jammu and Kashmir |
| Samia kohlli | Wild | Mizoram and Nagaland |
| Samia fulva | Wild, endemic | Andaman and Nicobar Islands |