International Journal of Applied Sciences and Biotechnology

80-93

Authors: Ashish Ghimire, Krishna Raj Pandey, Yagya Raj Joshi, Sobita Subedi

Mushrooms are known for several nutritional and medicinal benefits and are cultivated worldwide. Several fungal contaminants of mushrooms have been serving as the major restraining factor in the growing mushroom industry for a long time. Fungal contaminants like Trichoderma spp., Mycogone spp., Lecanicillium spp., Cladobotryum spp., Coprinus spp., Sependonium spp., Sclerotium rolfsii, and Cephalothecum roseum among many, are found to infect mushroom crops at different stages from spawn run period to maturation of fruiting bodies. These contaminants may reduce yield and/or degrade the quality of fruiting bodies of the mushroom causing economic losses. These contaminants are usually peculiar in terms of their symptomatology on the substrates, disease cycle, epidemiological requirements, and yield losses. Most of these contaminants come from poorly sterilized substrates. Several sterilization techniques like steam sterilization, hot water sterilization, alkalinization, bleaching, and chemical sterilization can be employed to eliminate pre-existing contaminants and each technique has its own relative advantage over others. Besides, biological control involving botanicals and live antagonists can also be used as prophylactic sterilant or as therapeutic sprays. Biological control measures are friendly to the environment and human health. Unlike chemical fungicides (used as sterilant or spray), biological control measures don’t inhibit mushroom mycelial growth and even don’t raise the problem of pesticide resistance in pathogens. Roguing out of infected mushroom fruiting bodies or beds, mushroom house sanitation, and management of vector population are also equally important in preventing the spread of the fungal diseases of mushrooms.

98-106

Authors: Dipendra Regmi, Mukti Ram Poudel, Bishwas K.C., Padam Bahadur Poudel

Wheat is the principal winter crop in Nepal. Drought affects 44% of the lands of the total wheat area in the country with a yield loss of 15–20%. This research focuses to minimize this loss through the identification of high-yielding lines stable across the drought stress and irrigated environments. The experiment was conducted in Alpha Lattice Design with 20 genotypes replicated twice with five blocks per replication from November 2019 to April 2020. The findings showed that genotypes, environments, and genotype-environment interaction have a highly significant effect on grain yield and explained 28.95%, 52.57%, and 18.47% of variation on yield, respectively. The which-won-where model revealed elite line NL 1420 is the most responsive line in the drought environment, followed by BL 4407, while elite line NL 1179 is the most stable line in irrigated environment. The mean vs stability model with principal component 1 and 2 explaining 65.76% and 34.24% respectively, showed that elite line NL 1420, BL 4407, BL 4919, Bhrikuti are both high yielding and stable lines while line NL 1179, Gautam, and NL 1384 are less stable in both test environments. Similarly, the ranking genotypes model indicated lines close to the ideal line are NL 1420, BL 4407, BL 4919, Bhrikuti as the most representative line for genotype evaluation. Thus, elite wheat line NL 1420 and NL 1179 are recommended as specifically adapted to drought and irrigated environments, respectively, and elite line NL 1420, BL 4407, BL 4919, Bhrikuti are recommended for further evaluation for stability.

113-121

Authors: Susmita Adhikari, Binod Thapa, Laxmi Poudel, Prativa Paudel, Ujjwal Acharya, Bibek Acharya, Sidda Lal Bohora

The field experiment was carried out during winter of 2018/19 with two varieties (Unnati and Surkhet-Local) and three plant geometry (15cm × 10 cm, 30cm × 10 cm, 45cm × 10cm) in Randomized complete block design (RCBD) with four replications. Statistically there was no difference between two varieties while differences were found on different spacing and interaction between variety and spacing on final seed yield. High significant differences on seed yield was due to spacing and yield of rapeseed were higher at the 30 cm inter row spacing as compared to the 15 cm and 45 cm inter row spacing. Statistically significant effect was found on mean values of seed yield for interaction which showed that Unnati cultivar in 30 cm x 10 cm plant geometry had the highest seed yield (969.86 kg/ha) followed by Surkhet-local with spacing of 15 cm × 10 cm (843.75 kg/ha) and 30 cm × 10 cm (823.76 kg/ha). Yield of these varieties decreased as spacing is increased, thus sowing of Unnati should be done at cropping geometry of 30 cm × 10 cm and for Surkhet-local it should not be done beyond 30 cm inter row spacing to get the maximum potential yield.

128-132

Authors: Surendra K. Gautam, Yasha Baid, Pabita Thapa Magar, Tirtha Raj Binadi, Bishow Regmi

Green chemistry refers to the design of chemical product and processes that reduce or eliminate the generation of hazardous substances. Silver nanoparticles (AgNPs) were synthesized successfully from AgNO3 through a simple green synthetic route using Ageratina adenophora leaf extract which acts as both reducing and capping agents. As synthesized AgNPs were characterized with the help of X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. XRD study shows crystalline nature of silver nanoparticles and average particle size was calculated as 24 nm using Debye Scherrer equation. Functional group responsible for the reduction of silver ion was investigated using FTIR spectroscopy. Hydroxyl group, amine group, aliphatic amine group were detected from FTIR analysis. Further, the green synthesized nanoparticles were found to be highly toxic against bacteria: Bacillus subtilis and Escherichia coli showing zone of inhibition of 11 mm and 9 mm, respectively.

138-151

Authors: Pramod Gyawali, Saugat Khanal, Jhalak Raj Joshi

A field survey was conducted in two districts­­ of western hills of Nepal during July-August, 2020 to study about the practices of traditional methods of horticultural crop disease management. A total of 125 farmers, 10 traders, 5 agro-vets, and 3 plant clinical doctors from four local bodies of two districts; Palpa and Gulmi, were selected for the interviews which employed a pretested questionnaire. Descriptive statistics were used to analyze the data. Almost half of the farmers interviewed (48%) were found to have an average level of knowledge regarding the application of indigenous methods. Mixture of kerosene and ash, mugwort solution, plant residues, bovine dung and urine, chilli powder, papaya leaves, onion mixed with garlic, etc. were popular as traditional techniques to effective control of disease and pest. Scaling technique used in this study showed the lack of indigenous information as the most serious constraint in adoption of traditional means, followed by lack of advertisement, poor social perception of farmers, and weak cooperation among social and agricultural scientists. The study recommended that documentation and scientific validation of indigenous means and support from government and extension agents are necessary to encourage farmers using traditional means. This study examines traditional diseases/pests control strategies implemented by the ancients and presently adopted in ongoing practices.