Browsing by Author "Alam, M. Shah"

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A Study of Fungal Diseases of Onion (Allium Cepa L.) with Special Reference to Purple Blotch
(University of Rajshahi, 2003) Tauhiduzzaman, Md.; Alam, M. Shah
Onion (Allium cepa L.) belonging to the family Alliaceae is one of the most important spice as well as vegetable crops of the world. Its origin is in Iran, Pakistan and the mountaineous region to the north of these countries (Purseglove, 1972). The primary center of origin of onion is central Asia and a secondary center for larger types of onion is Mediterranean regions (Mc Collum, 1976). Its use is neither limited to any climate nor associated with any nationality and it is probably as widely grown as any cultivated crop. The leading onion producing countries, in order of production are the United States of America, Japan, Spain, Egypt, Turkey and Italy (Jones & Mann, 1963). Onion is relatively high in food energy and is rich in calcium and riboflavin. It can be used as medicine. This crop can be grown over a wide range of conditions from sea level up to the elevation of about 1828 metre and from warm summer temperature of plains to cold weather down to a temperature of about l 6°C. However it is not suited to heavy rainfall and the rainfall should not exceed 762 mm during cultivating season (Aiyer, 1980). Onion grows in almost all districts of Bangladesh but widely cultivated in the greater districts of Faridpur, Dhaka, Rajshahi, Comilla. The onion cultivating area of Bangladesh covers 33000 ha. of land, total production 1,31,000 mt and total yield 3948 kg/ha (FAO, 2000). The local cultivars namely, Taherpuri, Jhitka, Salta, Kalasnagari and Faridpur bhati are mainly grown in the country (Rahim and Siddique, 1991). The crop suffers from many diseases (Meah and Khan, 1987; Ahmed and Hossain, 1985; Munoz et. al., 1984). Various kinds of diseases are found in the field as well as in the storage. About 45 different fungal and 5 bacterial species are reported to cause diseases of onion in the field. Five viral entities are also responsible for onion diseases in the field conditions, the percentage of infection and/or the extent ofloss due to diseases may vary from 0-100% (Harrison, 1954 and Vovk, 1959). A variety of disease and disorders affect onions and related crops in Ontario. Most of the diseases are caused by fungi or bacteria whereas disorders may be caused by adverse weather, air pollutions, soil conditions, nutritional imbalances and pest control products, sometimes several diseases and/or disorders can be present at the same time (J. Chaput, 1995). Purple blotch is one of the field disease caused by A/tern.aria porri (Ellis) Cif. is noted as the major disease in many onion growing countries including Bangladesh (CasteIJanos-Linares et. al., 1988; Rahman et. al., 1984; Ashrafuzzaman, 1977). Ahmed and Goyal (1988) mentioned that purple blotch, incited by A. porri is a major problem of onion (A. cepa) in India. The disease is a serious problem for seed production in tropical countries like Bangladesh (Rahman et. al., 1988; Anonymous, 1985). Initially symptoms appear on leaves or seed stalk as small water-soaked lesion that quickly develops white centers. As lesions enlarge, they become zonate and brown to purple, and are surrounded by a yellow zone. The lesion may be covered with brown to dark grey fruiting structures of the fungus. A few large or seed stalk and tissues distal to the lesions will die (Schwartz and Mohan, 1994). Purple blotch of onion causes breaking of floral stalks and thus the seed production is seriously affected. Damage of foliage and breaking of floral stalks due to the disease resulting in failure of seed production are common (Munoz et. al., 1984; Asrafuzzaman and Ahmed, 1976). The infected seed stalks break at the point where the lesion is developed (Singh, 1987). Under favorable environmental conditions for the disease complete failure of the crop may take place if appropriate control measures are not followed (Sharma, 1986).................................................
A Study on Aquatic Fungi in Diferent Water Bodies in and Around Rajshahi City
(University of Rajshahi, 2000) Das, Tapoti; Alam, M. Shah
The physico-chemical and biological conditions of three different sampling spots have been studied fortnightly from the month of November, 1998 to December 1999. Sampling spot one (SP-1) was situated on the northern side of the Rajshahi University Campus, behind the 3nl science building. Sampling spot two (SP-2) was polluted canal receiving effluent from the Horian sugar mills at Rajshahi. On the other hand sampling spot three (SP-3) was two kilometres away from SP-2 in the same canal receiving effluent from Katakhali Power Station at Rajshahi. These mixed effluent were discharged into the river Padma five kilometre from Katakhali Power station. The monthly mean value of different variables of three sampling spots were treated for each sampling spot.
A study on Black band disease of jute in the Northern part of Bangladesh
(University of Rajshahi, 2003) Ali, Md. Forman; Alam, M. Shah; Alam, M. Shahidul
Black band disease of jute ( Corchorus capsu/aris L. and C. olitorius L.) caused by lJoflyodip/odia theobromoe Pal. was studied during .lune' 1999 to October'200 I in Northern part of 13angladesh. The per cent or disec1sed jute plants were ranged between 19-27%. Optimum conidial germi1rntion of B. theobromae occurred al 25°-30°C, at pH 6 to 7 and at RH l 00%. The l'ungus prefer 1.5% glucose and l: l 5 (w/v) concentrations of cowclung sqlution for its conidial germination. Whereas, 1% KNO3 and NaNO3 salt solution gave better germination or conidia. The fungus freely germinates higher (93%) in river water compared lo those from other sources of waler. The highest mycelial growth c1nd dry weight orB. theobromac> was observed in PD;\ and lowest in Richard's medium. On the other hand. formation of conidia showed reverse effect in both the media. When the l'ungus was cultured on 20% cowdung medium showed better growth. 3%concentration of boron had good elTect on mycelial growth of B. rheobromae. Mustard oil cake is more favorable for the mycelial grovvth of B. theobromae than that or Linseed oil cake. Among the dirlercnt plant extracts tested, Datura mete/ medium showed better inhibition in culture. The growth or the llmgus was found to be affected by the different light conditions and heller growth was recorded in continuous light condition. -------
An integrated approach to the control of purple blotch of onion seed-crop.
(University of Rajshahi, 2000) Hossain, Md. Mozaffar; Alam, M. Shah
Onion (Allium cepa L.) is an important and widely used spice of Bangladesh. It is also used as vegetable all over the world. In Bangladesh, the greater districts of Faridpur, Pabna, Rajshahi, Dinajpur, Jessore, Dhaka and Camilla are the major onion growing areas. Its present production is around 1,48,000 mt against the requirement of one million ton estimated on a modest requirement of 25 g/capita/day (Hossain and Islam, 1993). The local cultivars namely, Taherpuri, Jhitka, Salta, Kalasnagari and Faridpur bhati are mainly grown in the country (Rahim and Siddique, 1991 ). The crop suffers from many diseases (Meah and Khan, 1987; Ahmed and Hossain, 1985; Munoz et al., 1984). Among them purple blotch caused by Alternaria porri (Ellis) Cif. is noted as the major disease in many onion growing countries including Bangladesh (CastellanosLinares et al., 1988; Rahman et al., 1988; Meah and Khan, 1987; Bose and Som, 1986; Ahmed and Hossain, 1985; Munoz et al., 1984; Ashrafuzzaman, 1977). Ahmed and Goyal (1988) mentioned that purple blotch, incited by A. porri, is a major problem of onion (Allium cepa) in India.
Design of a Broadband Single Mode Hybrid Plasmonic Waveguide Incorporating Silicon Nanowire
(Optical Materials Express, 2020-01-03) Hasan, K. B. M. Rakib; Islam, Md. Asiful; Alam, M. Shah
In this work, we proposed a hybrid plasmonic waveguide for bulk index sensing, which is compatible with Mach-Zehnder interferometer sensing arrangement. The modal properties of the guiding geometry are investigated using the finite element method. This waveguide supports a long-ranging hybrid plasmon mode, which is highly confined in nanofluidic analytic channel due to the optical capacitance effect. Thus, an improved bio sensing performance is demonstrated with high Figure of merit at the telecommunication wavelength. The sensing performance is also analyzed here for a broad range of operating wavelength in order to examine the multi wavelength operability of the proposed hybrid plasmonic waveguide biosensor.
Incidence of Red Rot Disease of Sugarcane in Thakurgaon and Rajshahi Areas with Especial Reference to Ecological Factors
(University of Rajshahi, 2006) Kabir, Md. Humayun; Rahman, M. Shamsur; Alam, M. Shah
A set of biotic and abiotic habitat factors that determine the distribution, growth and reproduction of species. Physiochemical I. e. abiotic factors are fundamentally important. They vary from place to place. For each abiotic factor, a species possesses an amount of tolerance within which it can grow and reproduce. Different sugarcane varieties display different sets of tolerance ranges and these are reflected in their forms and functions i.e., in their vegetative organs. That is why ecologists pay greater attention to the vegetative parts of plants than to their floral ones, as the floral parts remain unchanged even under diverse habitat conditions. According to Moore et al. (1986) any adaptation of sugarcane to any environment induces morphological, anatomical, pathological and physiological changes. According to Stocker (1960) the structural modifications occur in nature due to the scarcity of water. Water and light greatly influence the external and internal structure of sugarcane as well as their physiological process. Sugarcane varieties that prefer wet/or moist habitats are hygrophytes and those that can adjust 1.0 drier habitats are xerophytes. Most of the xerophyte’s arc· sun loving and are known as helophytes, while most of the hygrophytes are shade loving and are known as schizophytes. Species without any Eco phenic and/or ecotype variations are adapted only to a fixed combination of environmental factors and have very narrow ecological amplitude, while those with much variation can fit into a wide range of habitat conditions and hence have wide ecological amplitude (Daubenmire, 1959). Wild uncultivated-sugarcane appears to have broad ecological amplitude. About 300000 species of plants have so far been identified in our planet, while tens of thousands more remain undiscovered. Of these only 1500 species (about 0.5%) are nurtured for food, fodder, fiber, timber, medicine, sugar, beverage and flowers.