International Journal of Applied Sciences and Biotechnology

1-7

Authors: Roman Pandey

Black shank, caused by Phytophthora nicotianae, and Fusarium wilt, caused by the Fusarium oxysporium f. sp. nicotianae, are major diseases affecting tobacco crops globally. Phytophthora nicotianae is primarily found in tropical and subtropical regions and infects tobacco plants by producing zoospores that swim to root tissue and form cysts. Symptoms of black shank include root and crown rot, wilting, leaf chlorosis, stem lesions, and pith necrosis. Management strategies for black shank include cultural practices, chemical treatments, and host resistance. Chemical fungicides, such as metalaxyl or mefenoxam, oxathiapiprolin, and fluopicolide, can be used but there is a risk of fungicide resistance. Fusarium wilt is characterized by yellowing, drying, and death of leaves, leading to the death of the entire plant. Control measures for Fusarium wilt include plant resistance, cleanliness, crop rotation, nutrition, nematode management, and fumigation or biofumigation. The most successful control of Fusarium wilt has been through the use of resistant tobacco cultivars. The impact of rotation crops and resistant plants on the pathogen populations in the soil must be evaluated and soil pH and calcium levels may also impact the disease. The presence of the fungus in a field can last for several years without a vulnerable host.

15-24

Authors: Manoj Kumar Shah, Luma Nidhi Pandey, Rupa Bastola, Bimala Shah, Shatrughan Shah

This study was commissioned to assess studies on feeding resources and feeding management of goat in mid hills of Nepal. During the study, 162 goat farms located in Ghiring and Baradi of Tanahun districts in Nepal were surveyed, and a semi-structured questionnaire was administered to each farm. Farmers in this region prefer integrating livestock raising with crop production. The majority of the farms surveyed kept indigenous Khari goats, either in pure flocks or through crossbreeding. The types of goat farming were commercial (8.02%), semi-commercial (29.01%) and subsistence (62.96%). The nature of management practices for goat farmers was intensive (70.99%), semi-intensive (14.81%) and free range (14.20%). Farmers grazed their livestock in different locations, including their own land (48.77%), forests (22.22%), and other places (29.01%). The selection of fodder species by farmers varied depending on the availability of different species in the mid hills, reflecting differences in their perception and preference. Among the top fodder species highly preferred by the farmer in summer season are Ficus cunia followed by Bauhinia longifolia, Ficus hispida, Castanopsis indica and Ficus auriculata. Fodder species highly preferred by the farmers in winter season are Litsea polyantha followed by Drepanostachyum khasianum, Shorea robusta, Terminalia elliptica and Mangifera indica. Goat production is an essential aspect of subsistence farming, providing both meat and cash income. Consequently, this study recommends promoting locally preferred tree fodder species and supplementing them with feed during different seasons, based on their availability and local preferences. Such strategies can help to improve goat production and support sustainable livelihoods for farmers in the region.

30-36

Authors: Ram P Mainali, Sunmoon Jyakhwa

Nepal possesses a rich diversity of cucumber landraces and their wild relatives. The first step towards harnessing the potential of these landraces in crop improvement programs is to identify the amount of genetic variation present among them. This research aimed to evaluate 18 cucumber accessions collected from different regions of Nepal and assess their agro-morphological variation in terms of yield and yield-associated traits under polyhouse condition. A research trial was conducted using Randomized Complete Block Design with two replicates at the National Agriculture Genetic Resources Centre (NAGRC), Khumaltar in 2019. The accessions were characterized using various qualitative and quantitative descriptors, with six focusing on traits related to the fruits of the plant and three on phenology and morphology. The results revealed significant variations among the genotypes for all studied traits. Bhaktapur Local was an excellent genotype for recording yield and associated traits, like fruit dimension, number of fruits per plant and yield per plant, making it the most promising genotype, however, Genebank accessions, such as NGRC08671, NGRC07716 and NGRC08668 could be excellent choices for yield associated traits. Correlation analysis indicated a positive relationship between yield and fruit length, fruit width, and total number of fruits per plant, while vine length was positively correlated with the total number of fruits produced per plant. This study identified several genotypes with desirable traits for yield and yield-associated characteristics, which could be valuable in the development of high-yielding cucumber varieties with superior morphological and agronomic traits in the future.

42-53

Authors: Hamadou Abdou, Ekengele Nga Léopold, Mahamat Seid Ali Malloum, Dieudonné Bitom

The main objective of this study was to assess the level of metal contamination of the soils used in the cultivation of onions in the city of Abéché. Thus, 04 plots were carried out and monitored for a period of five years (05 years). Two traditional plots were chosen in the Arkou site; and two control plots were carried out in the Bagarine site. Soil samples were taken annually (2016 to 2020) after harvesting on a thickness of 0 and 20 cm. In each plot, thirteen (13) samples were taken. After quartering, one (01) representative sample from each plot was retained. The samples were analyzed by optical emission spectrometry at the Food Quality Control Center Laboratory (FQCCL) in Ndjamena. The determination of heavy metal concentrations revealed relatively low levels for Ni, Zn, Cu, Cr and Fe. These levels are generally lower than the reference values ​​for all the plots. Geoaccumulation indices (Igeo) and Contamination factor (Cf) revealed pollution indices. Pb and Cd show contaminations in traditional plots. The correlations (P < 0.05) observed in our study area are positive and significant. This study shows that the use of chemical inputs are sources of soil contamination by heavy metals.