ANNUAL REPORT - Department of Biotechnology

quantitative trait loci (QTL) for cocoon weight,
cocoon shell weight and identification of DNA
markers linked to the QTLs in the silkworm (B. mori)
jointly at Andhra Pradesh State Sericulture Research
and Development Institute, Hindupur and CDFD,
Hyderabad. Two silkworm lines with lower (Nistari)
and higher (CSR2) quantitative traits for cocoon
weight and cocoon shell weight were selected as
initial parents for raising F-1 generation. Using the F-
1 population, eight back crosses (four each as direct
crosses and reciprocal croses) were made to
develop mapping population with linkage
disequilibrium. In addition, two F-2 generations were
also developed for raising bulked segregant
population. From each cross, individual cocoons
(both male and female) were assessed for the
desired traits. A network project on phylogeography
of tropical tasar (Antheraea mylitta) and muga
silkworm (A. assama) has been continued involving
three institutions: Seribiotech Research Laboratory,
Bangalore, Central Tasar Research and Training
Institute, Ranchi and Central Muga Eri Research and
Training Institute, Jorhat. Microsatellite analysis
carried out in muga silkworm populations indicated
genetic variability in hill populations in comparison
with the plain area populations. Tasar silkworm
populations exhibited intra-and inter- population
vaiability when amplified with SSR anchored marker
system.
Cocoon of different ecotypes of tropical tasar
silkworm (Antheraea mylitta)
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Development of control measures for major
diseases of silkworm
At Central Sericultural Research and Training
Institute, Mysore, a Bombyx mori gene that code for
antiviral protein has been partially characterized. The
partial sequence of gene (644 bp) encoding the
protein showed homology with NADPH
oxidoreductase and xanthine dehydrogenase
proteins.
Silkworm larvae fed on mulberry leaves
supplemented with Lactobacillus plantarum, a
probiotic showed significant increase in weigh of
larva, cocoon and pupa; including shell ratio and
pupation rate as compared to control groups at the
BAIF Development Research Foundation, Pune.
Feeding of silkworm larvae (III moult) with L.
plantarum and Sporobolomyces roseus and then
treating with Bm NPV showed significant increase in
larval weight and survival percentage as compared to
controls. Effect of probiotics varied among different
silkworm races when treated with Bm NPV. Studies
have also been initiated on epidemiology, spatial and
temporal dynamics of diseases of muga silkworm (A.
assama) alongwith the identification and
characterization of their causal agents jointly at
Assam Agricultural University, Jorhat and Central
Muga Eri Research and Training Institute, Jorhat.
Silkworm Genome Programme
Under the International Consortium on Lepidopteran
genome project, the muga silkworm (Antheraea
assama) transcriptome has been investigated by
generating over 35,000 ESTs which resulted in the
identification of over 8200 unique putative genes at
CDFD, Hyderabad. Functional annotation of these
revealed several genes that are involved in silk
production, circadian rhythm, sex determination,
immune response and also several novel tissue
specific genes. Digital differential display showed
over 1000 transcripts expressing only in testes.
Similarly, ESTs that code for fibroin and sericin were
also identified. Preliminary analysis of fibroin and
sericin shows that silk proteins of A. assama are quite
distinct from those of Bombycids. Comparative
Research and Development