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Chattopadhyay S.,Regional Muga Research Station | Chattopadhyay S.,Central Sericultural Research and Training Institute | Sangma C.D.,Regional Muga Research Station | Tikader A.,Regional Muga Research Station | And 2 more authors.
Tropical Plant Pathology | Year: 2014

Som (Persea bombycina) is an economically important tree used as food source by the muga silkworm, Antheraea assamensis. Phyllactinia leaf spot (PLS), caused by Phyllosticta persae, affects all som cultivars during June to September (rainy season) and is responsible for foliage losses up to 26%. Information about the effect of this disease at the farmer level and host resistance is lacking. PLS severity was assessed in six major sericulture areas of Assam, India. Furthermore, eight clones were evaluated for resistance in experimental field trials. Disease incidence and severity index (DSI), area under disease progress curve (AUDPC), apparent infection rate, lesion diameter and frequency all indicated differences among clones. DSI and AUDPC values were 3.6 fold and 4.2 fold higher in the most susceptible accession M-8 compared to M-5. High broad sense heritability (h2 = 0.80) of DSI suggested an additive nature of resistance. Correlations of DSI (r range: 0.55 to 0.91) with other parameters provided a good empirical evidence of obtained PLS responsiveness. M-5 showed partial resistance on the basis of all measures and appeared as the most diverse accession based on Euclidean distance. These results suggested that clone M-5 may be a potential source of resistance for use in PLS breeding programs. © by the Brazilian Phytopathological Society.

Tikader A.,Central Silk Board | Saha R.K.,Research Extension Center | Chattopadhaya S.,Regional Muga Research Station | Biswas N.,Research Extension Center
Indian Silk | Year: 2012

Muga culture hitherto restricted to Assam, is being popularized in the areas with similar climatic conditions like Coochbehar of West Bengal which is endowed with food plantations in the forest areas, with the focus on augmentation of food plantation and creation of infrastructure under CDP in the last two Plans. The article presents the scenario of muga culture and the developmental activities initiated in the area that have started yielding encouraging results.

Tikader A.,Regional Muga Research Station | Gogoi A.K.,Regional Muga Research Station | Pachuau L.,Regional Muga Research Station
Indian Silk | Year: 2012

It is often said that sericulture comes to the rescue of the farmers in distress and rightly so, in case of Shri Holiram Rabha, a farmer from a remote village in Assam. He hardly believed that taking to muga culture and muga seed production would change his destiny. Thanks to his hard work, commitment and dedication; today, he is a successful muga sericulturist, and life has changed for the better for him.

Singh G.R.,Regional Muga Research Station | Kiran Kumar K.R.,Central Tasar Research and Training Institute | Sinha A.K.,Central Tasar Research and Training Institute
Indian Silk | Year: 2012

Virosis caused by CPV is causing higher mortality in tasar culture. Different preventive methods presently adopted are having their own limitations as tasar culture is done outdoors. CTR&TI, Ranchi has come out with a botanical formulation "Jeevan Sudha", the lab and field trials of which have shown promising results in effectively controlling the disease.

Tikader A.,Regional Muga Research Station | Gogoi A.K.,Regional Muga Research Station | Phukan J.C.D.,Research Extension Center
Indian Silk | Year: 2012

Meghalaya, ideally endowed with the conducive climatic conditions for muga culture has the culture of sericulture and silk, as its heritage. Of late, thrust has been given on creation of required infrastructure and skill development. Presented here is a detailed profile of the muga culture in the state.

Sahu A.K.,Regional Muga Research Station | Bindroo B.B.,Regional Sericultural Research Station | Gogol P.R.,Regional Muga Research Station
Indian Silk | Year: 2010

A comparison of complete indoor rearing performance of four wild genetic stocks of muga silkworm during December-January 2007 with the outdoor rearing during the same period is discussed. During the Jarua pre-seed crop 951 dfls were brushed on Soalu plants after adopting all recommended prophylactic measures starting from pre-treatment of plants and maintenance of hygienic conditions in the rearing field. The disinfected Soalu leaves / twigs were allowed to surface dry and placed in wide mouthed earthen pots filled with sand upto 2/3 level and water. The pot with the Soalu twig and the worms thereon were covered with a perforated polythene cubicle till second instar, only to maintain optimum relative humidity level. ERR was recorded as 80.77%, 67.75%, 69.72% and 61% in Aa00-1, Aa00-2, Aa00-3 and Aa00-4, respectively with a larval period of 38 days as against 45-50 days in general outdoor rearing during the Jarua crop. Muscardine incidence was not recorded in the indoor reared worms.

Chattopadhyay S.,Central Sericultural Research and Training Institute | Chattopadhyay S.,Regional Muga Research Station | Ali K.A.,Central Sericultural Research and Training Institute | Doss S.G.,Central Sericultural Research and Training Institute | And 5 more authors.
AoB PLANTS | Year: 2011

Background and aims Micro-morphological characteristics can influence fungal infectivity. We sought links between micro-morphology and resistance to powdery mildew in mulberry with the intention of assisting selection of disease-resistant lines. Methodology Over 3 years and under field conditions, we evaluated 30 lines of mulberry with contrasting susceptibilities to powdery mildew (15 resistant and 15 susceptible). Disease severity was related statistically to stomatal area, stomatal density, stomatal index, upper and lower cuticular thicknesses, leaf thickness and trichome density. Principal results Differences between lines were significant (P < 0.05) for all characters studied. Variation between the resistant and susceptible groups was statistically highly significant (P < 0.01) for stomatal index, stomatal area and trichome density. The powdery mildew-resistant group was distinguished by 17.4 % lower stomatal density, 12.5 % smaller stomatal index per unit leaf area, 20.0 % greater trichome density and 18.0 % higher stomatal area compared with the susceptible group. Trichome density was negatively correlated with disease severity index and with the accumulative area under disease progression curves. Stomatal density was positively correlated with both measures of disease severity. Although stomatal area was negatively related to disease severity index (r = -0.28; P < 0.05), the correlation was weak. There was no statistically significant relationship between stomatal area and the accumulative area under disease progression curves. The germplasm was partitioned into seven sub-groups based on hierarchical cluster analysis derived from pooled disease severity index scores and three highly significant micro-morphological characters. Eighty per cent of the resistant germplasm accumulated in three cluster components (A1, A2 and B2) characterized by high trichome densities and a high stomatal density and stomatal index. © The Authors 2011.

Chattopadhyay S.,Regional Muga Research Station | Tikader A.,Regional Muga Research Station | Das N.K.,Central Sericultural Research and Training Institute
Photosynthetica | Year: 2011

Nondestructive approach of modeling leaf area could be useful for plant growth estimation especially when number of available plants is limited and/or experiment demands repeated estimation of leaf area over a time scale. A total of 1,280 leaves were selected randomly from eight different morphotypes of som (Persea bombycina) established at randomized complete block design under recommended cultural regimes in field. Maximum leaf laminar width (B), length (L) and their squares B 2, L 2; leaf area (LA), and lamina length × width (L×B) were determined over two successive seasons. Leaf parameters were significantly affected by morphotypes; but seasons had nonsignificant impacts on tested features. Therefore, pooled seasonal morphotype means of each parameter were used to establish relationship with LA. L and its square L 2 did not provide accurate models for LA predictions. Considerably better models were obtained by using B (y = 2.984 + 7.9664 x, R 2 = 0.615, P≥0.001, n = 119) and B 2 (y = 12.784+ 0.9604 x, R 2 = 0.605, P≥0.001, n = 119) as independent variables. However, maximum accuracy of prediction of LA could be achieved through a simple linear relationship of L×B (y = 8.2203 + 0.4224 x, R 2 = 0.843, P≥0.0001, n = 119). The model (LA:L×B) was validated with randomly selected leaf samples (n = 360) of som morphotypes and highly significant (P≤0.001) linear function was found between actual and predicted LAs. Therefore, the last model may consider adequate to predict leaf area of all cultivars of som with sufficient fidelity. © 2011 Springer Science+Business Media B.V.

Sahu A.K.,Regional Muga Research Station
Indian Silk | Year: 2010

The bamboo mountage was fabricated adopting the principle and design of the box type mountage, at the cost of Rs.550. The bamboo mountages were supplied to Research Extension Centers located at North Lakhimpur, Assam; Coochbehar, West Bengal; Tura, and West Garo Hills, Meghalaya for assessing its performance at farmer's level. The procedure involves maintaining at least 3 replications of the bamboo mountage and the control for comparison and keeping the bamboo mountage vertically for overnight after mounting the silkworms, for equal distribution in the chamber. About 90.18% of space in the spinning hall could be saved in case of the bamboo mountage for mounting 1000 worms as compared to Jail. Bamboo mountage eliminates the escape of worms unlike Jali. The ripe worms can easily find anchorage for spinning without wasting silk; thus, forming quality cocoons with higher rate of cocooning.

Chattopadhyay S.,Central Sericultural Research and Training Institute | Chattopadhyay S.,Regional Muga Research Station | Ali K.A.,Central Sericultural Research and Training Institute | Doss S.G.,Central Sericultural Research and Training Institute | And 5 more authors.
Journal of General Plant Pathology | Year: 2010

Powdery mildew caused by the ascomycete Phyllactinia guttata (syn. P. corylea) is a major foliar disease worldwide of the unique mulberry (Morus spp.) for silkworm feed. Genetic resistance to powdery mildew, the most sustainable and economical strategy for disease control, is still elusive for tropical mulberry. About 147 germplasm sources, representing 18 countries of origin, were screened for resistance to P. guttata in six seasonal fields and greenhouse trials after exposure to natural and artificial inoculum, respectively. In the field, the level of plant responsiveness to disease was assessed from 30 to 62 days after pruning in each season as variations in the disease severity index (DSI), disease incidence (DI%) and area under the disease progress curve (AUDPC). These measures differed significantly among the germplasm. Of 147 germplasm sources, ~6.8% had useful resistance (two high and nine moderately resistant) to the powdery mildew pathogen on the basis of DSI. The AUDPC values were 13.5-fold higher in the most susceptible accession-(Philippines) than the least responsive (Vietnam-2). The results of DSI were strongly correlated with the obtained DI values (r = 0.92; P < 0.01) and AUDPC (r = 0.89; P < 0.01). Moreover, field screening results were highly correlated (R2 = 0.839) with values from the greenhouse evaluation using artificial inoculum. However, the DSI values in field and greenhouse screenings for three sources (Non-nayapati, Nao-khurkul and Tista Valley) varied significantly. A relatively low disease reaction of 09 resources (Vietnam-2, Ankara and 07 others) using different assessment scales after natural and artificial inoculation prove, for the first time, that they have potential in breeding for resistance in tropical mulberry to powdery mildew. © 2010 The Phytopathological Society of Japan and Springer.

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