Central Sericultural Germplasm Resources Center

Hosūr, India

Central Sericultural Germplasm Resources Center

Hosūr, India
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Jingade A.H.,Central Sericultural Germplasm Resources Center | Vijayan K.,Academia Sinica, Taiwan | Somasundaram P.,Central Sericultural Germplasm Resources Center | Srivasababu G.K.,Central Sericultural Germplasm Resources Center | Kamble C.K.,Central Sericultural Germplasm Resources Center
Journal of Insect Science | Year: 2011

Silkworm genebanks assume paramount importance as the reservoirs of biodiversity and source of alleles that can be easily retrieved for genetic enhancement of popular breeds. More than 4000 Bombyx mori L (Lepidoptera: Bombycidae) strains are currently available and these strains are maintained through continuous sibling mating. This repeated sibling mating makes the populations of each strain more homozygous, but leads to loss of unique and valuable genes through the process of inbreeding depression. Hence, it is essential to maintain a minimal degree of heterozygosity within the population of each silkworm strain, especially in the traditional geographic strains, to avoid such loss. As a result, accurate estimation of genetic diversity is becoming more important in silkworm genetic resources conservation. Application of molecular markers help estimate genetic diversity much more accurately than that of morphological traits. Since a minimal amount of heterozygosity in each silkworm strain is essential for better conservation by avoiding inbreeding depression, this article overviews both theoretical and practical importance of heterozygosity together with impacts of inbreeding depression and the merits and demerits of neutral molecular markers for measurements of both heterozygosity and inbreeding depression in the silkworm Bombyx mori.


Jingade Anuradha H.,Central Sericultural Germplasm Resources Center | Vijayan K.,Research Coordination Section | Nair C.V.,Central Sericultural Germplasm Resources Center | Manjula A.,Central Sericultural Germplasm Resources Center
Emirates Journal of Food and Agriculture | Year: 2013

The purity of DNA is one of the major factors affecting the success of Genomic studies. Nucleic acid isolation from polyphenol rich plants fail to produce good quality DNA or RNA as polyphenols adhere and interfere with DNA during isolation. An improvised, simple and inexpensive protocol has been developed for extracting genomic DNA from Mulberry (Morus spp.). The purity of the DNA as revealed by the ratios of absorbance at 260/280 nm (A 260/280) and 260/230 nm (A 260/230) was closer to 2.0. Genomic DNA analyzed for analytical applications like restriction digestion and PCR amplification with molecular markers viz., Inter Simple Sequence Repeats (ISSR), Random Amplified Polymorphic DNA (RAPD) and Simple Sequence Repeat (SSR) primers further confirmed the purity of the DNA. A modified method of silver staining was employed for the resolution of SSR amplified products. Physiologically mature leaf was found more suitable for getting quality DNA in mulberry.


Jingade A.H.,Central Sericultural Germplasm Resources Center | Srinivasa Babu G.K.,Central Sericultural Germplasm Resources Center | Lekha G.,Central Sericultural Germplasm Resources Center | Nair C.V.,Central Sericultural Germplasm Resources Center | And 2 more authors.
Cryo-Letters | Year: 2013

Embryo cryopreservation offers a way to safeguard against unwelcome mutations and inadvertent selection that can change its unique genetic makeup. Having a genetic repository of the silkworm genetic resources would ensure preservation of original genetic makeup and will permit to study what genes may have been lost in the selection process. For cryopreservation of eggs and embryos of silkworm, the determination of embryonic stages is a prerequisite. This study reports microscopic observations on embryonic development. The embryonic stages in the dechorionated eggs were determined in parallel comparison with the embryos isolated from intact eggs of different developmental ages. © CryoLetters, businessoffice@cryoletters.org.


Krishnan R.R.,Central Sericultural Research and Training Institute | Sumathy R.,Central Sericultural Research and Training Institute | Ramesh S.R.,Central Sericultural Germplasm Resources Center | Bindroo B.B.,Central Sericultural Research and Training Institute | Naik G.V.,Central Sericultural Research and Training Institute
Crop Science | Year: 2014

Sampling core collections containing a diverse set of entries has been practiced over the last two decades for a number of crops and has become a vital component of modern day crop improvement programs. A diverse, multipurpose core collection should represent the maximum genetic diversity available in an entire germplasm collection with a small number of entries. Selection of genetically distant entries that represent the maximum diversity of the entire germplasm collection is a challenging task that has been improved over the years. In this study, we introduce the similarity elimination (SimEli) method to sample genetically distant entries for the development of core collections, which was used to sample a diverse core collection of mulberry accessions using phenotypic markers. The performance of the SimEli method was compared with that of the PowerCore algorithm for phenotypic markers and with that of the Core Hunter and genetic distance optimization (GDOpt) algorithms for simple sequence repeat (SSR) markers. The SimEli method effectively selected genetically distant entries, whereas PowerCore proved efficient for selecting outliers among a small number of entries. However, the SimEli method outperformed the Core Hunter algorithm in selecting distant entries with high mean and minimum entry to nearest entry distance values. The Core Hunter collections retained a greater number of alleles than did collections developed using the SimEli method only when increased weight was given to Shannon's diversity index when using Core Hunter. The SimEli method is more user-friendly, involves simple steps, and requires less computational time than other leading programs for the development of core collections. © Crop Science Society of America.


Gowda V.,Central Sericultural Germplasm Resources Center | Ashwath S.K.,Central Silkworm Central Sericultural Research and Training Institute | Kalpana G.V.,P4 Basic Seed Farm
Indian Journal of Sericulture | Year: 2012

In the present study, with the main aim of identifying the promising four-way cross bivoltine hybrid combinations with superior quantitative and qualitative traits, an attempt has been made to assess and evaluate newly developed four-way cross hybrids of bivoltine silkworm Bombyx mori L. Using oval and dumb-bell bivoltine foundation crosses, a total of 45 four-way cross hybrids were prepared, reared and assessed through multiple trait evaluation index (E.I.) along with the control (CSR2xCSR27) x (CSR6xCSR26). The data showed that21 double hybrids have mean E. I. values > 50, which were significantly higher when compared to the control, where the mean E.I. value was found to be only 44.15. The highest E.I. value of 56.11 was recorded in the four-way cross (CSR2 x JPN8) x (D13xSl) closely followed by 55.14 in (CSR2xCSR12) x (CSROxSl) and 54.61 in (CSR2xJPN8) x (CSR26xSl). Results of the present investigation have shown the prospects of identifying promising four-way cross bivoltine hybrids for commercil exploitation.


Gowda V.,Central Sericultural Germplasm Resources Center | Ashwath S.K.,Central Sericultural Research and Training Institute | Kalpana G.V.,P4 Basic Seed Farm | Rekha M.,Central Sericultural Research and Training Institute | Bindroo B.B.,Central Sericultural Research and Training Institute
Indian Journal of Sericulture | Year: 2014

Genotype-environment (G-E) interaction and stability parameters were analyzed for ten each of oval and dumb bell silkworm bivoltine breeds reared during three different seasons of the year. Quantitative economic traits viz., fecundity, cocoon yield /10000 larvae by number, cocoon yield /10000 larvae by weight, single cocoon weight, single shell weight, cocoon shell percentage, filament length, denier, raw silk percentage, renditta, neatness and boil-off loss were evaluated. The mean sum of squares (MS) for the breeds and environments was highly significant (p < 0.01) in both oval and dumbbell breeds in respect of all the traits except for renditta clearly indicating substantial variation among the breeds and seasons. However, the Genotype Environment interaction was found to be nonsignificant for all the traits among oval breeds, while among the dumbbells, only four traits, namely, cocoon yield /10000 larvae by number, cocoon yield/10000 larvae by weight, filament length and neatness showed significant G E interaction. Two stability parameters, viz., regression coefficient (bi) and deviation from regression (s2di) were analyzed in both oval and dumbbell breeds, which showed significant differences for most of the traits. Based on the values of the two stability parameters for the 12 economic traits and cumulative ranking, CSR2, JPN8 among oval breeds and CSR16 among dumbbell breeds were found to be stable breeds in the expression of quantitative traits irrespective of the seasons, while, S5 (oval) and BBE267 (dumb-bell) expressed less stability.


Krishnan R.R.,Central Sericultural Research and Training Institute | Naik V.G.,Central Sericultural Research and Training Institute | Ramesh S.R.,Central Sericultural Germplasm Resources Center | Qadri S.M.H.,Central Sericultural Research and Training Institute
Plant Genetic Resources: Characterisation and Utilisation | Year: 2014

The secret art of silk culture along with mulberry seeds is presumed to have spread from China to other parts of the world including India through the famous Silk Road. In this study, we investigated a set of 36 important mulberry genotypes (designated as 'breeders' collection') of historical importance that have been frequently used in Indian crop improvement programmes over the last five decades. This study is the first to employ a large number of microsatellite markers (140 screened; 70 used for profiling) to elucidate the diversity, structure and breeding history of mulberry. The cluster and STRUCTURE analysis corroborated with the known genetic relationships and origin. The groupings by STRUCTURE (k= 4) confirm parallel breeding efforts undertaken in the eastern, southern and northern regions of the country. The cultivar 'Mysore Local' shares a common parent with 'Berhampore Local', and this supports the historical records of its introduction from eastern India to the Kingdom of Mysore by the erstwhile ruler Tippu Sultan. The popular variety 'Kanva-2' shared a common male parent with the Japanese variety 'Kousen', supporting the contribution of exotic progenitors in Indian cultivars. The findings of this study will be useful in formulating new strategies for mulberry improvement and reveals the historical events of the introduction and spread of cultivated mulberry in the Indian subcontinent. © 2013 NIAB.


Rao Ananda A.,Central Sericultural Germplasm Resources Center | Vijayan K.,RCS | Krubakaran M.,Central Sericultural Germplasm Resources Center | Borpujari M.M.,Central Sericultural Germplasm Resources Center | Kamble C.K.,Central Sericultural Germplasm Resources Center
Journal of Horticultural Science and Biotechnology | Year: 2011

Nine isozyme patterns were studied to deduce the level of genetic diversity and inter-relationships among 14 species of mulberry (Morus spp. L) used in breeding programmes. -Esterase (EST), peroxidase (PoX), diaphorase (DIA), and polyphenol oxidase (PPO) produced 12 isozyme loci and a total of 22 alleles.The percentage of polymorphic loci and the average number of alleles per locus ranged from 50 - 75% and 1.336 - 1.667 respectively. Among 80 wild accessions of two wild and two domesticated species of Morus, 22 accessions of M. alba exhibited a higher number of polymorphic loci (75%), a higher polymorphic index (0.398), average number of alleles per locus (1.457), and expected heterozygosity (0.339) compared to the three other Morus species under study. Evidence for a higher rate of gene flow was found between populations of M. alba and M. indica compared to that between the other three species sampled. Phylogenetic clustering of the 80 wild mulberry accessions indicated three major groups. Accessions of the domesticated species grouped into one cluster, while accessions of the wild species grouped into one major and one minor cluster. Among all the isozyme loci, EST-2 was present only in polyploid species. The resolving power of isozymes was less than that of molecular markers, hence molecular markers should be used for phylogenetic studies in mulberry.


Saravanakumar R.,Central Sericultural Germplasm Resources Center | Ponnuvel K.M.,Central Sericultural Germplasm Resources Center | Qadri S.M.H.,Central Sericultural Germplasm Resources Center
Entomologia Experimentalis et Applicata | Year: 2010

Conservation of silkworm [Bombyx mori L. (Lepidoptera: Bombycidae)] germplasm aids in prevention of genetic erosion and race extinction. Multivoltine silkworm germplasm maintenance involves rearing five generations per year and this requires expenditure, manpower, and infrastructure, in addition to frequent exposure of the silkworms to diseases, pests, and predators. To minimize these problems, an alternative protocol was developed by way of induction of egg diapause in the multivoltine silkworms through rearing of the fourth and fifth instars at low temperature (18-20 °C) under regulated photoperiod (L6:D18). This method allowed induction of egg diapause in the selected races at levels ranging from 26 to 94% and the diapause-induced eggs were maintained under cold preservation conditions. The stability of genotypic characters was confirmed in the diapause-induced silkworm batches after the seventh generation, by comparison with control batches of silkworm using inter simple sequence repeat-polymerase chain reaction (ISSR-PCR). Analysis of Nei's genetic distance for the different races indicated no significant variation between control and diapause-induced races. This reveals that all the selected races maintained genetic stability even after the seventh generation at the phenotypic and molecular level. Hence, it can be concluded that induction of egg diapause is an appropriate alternative method to preserve multivoltine races for longer periods of time. © 2010 The Authors. Journal compilation © 2010 The Netherlands Entomological Society.


PubMed | Central Sericultural Germplasm Resources Center
Type: Journal Article | Journal: Cryo letters | Year: 2013

Embryo cryopreservation offers a way to safeguard against unwelcome mutations and inadvertent selection that can change its unique genetic makeup. Having a genetic repository of the silkworm genetic resources would ensure preservation of original genetic makeup and will permit to study what genes may have been lost in the selection process. For cryopreservation of eggs and embryos of silkworm, the determination of embryonic stages is a prerequisite. This study reports microscopic observations on embryonic development. The embryonic stages in the dechorionated eggs were determined in parallel comparison with the embryos isolated from intact eggs of different developmental ages.

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