Effect of Nitrogen Rates on Leaf Quality of Two Cassava (Manihot Esculenta Crantz) Varieties as a Feed for Eri-Silkworm (Samia Cynthia Ricini Boisduval) Cocoon Production at Jimma, Southwest Ethiopia

Abstract

Limited research efforts have been made on cassava leaf usage for rearing eri-silkworm in relation to nitrogen fertilizer management. Hence, field and laboratory experiments were conducted at Jimma University (Ela-dale Site) during 2016 with the objective of determining the effect of nitrogen on leaf quality and identifying appropriate cassava variety for better leaf quality as a feed for Eri-silkworm performance. A 2x5 factorial experiment arranged in Randomized Complete Block Design (RCBD) with three replications was used. The treatments consisted of two cassava varieties (Kello and Qulle) and five levels of N (0,40,80,120 and 160 kg N ha-1) as Urea. For the laboratory experiment, to rear eri-silkworm, cassava leaves harvested from the field experiment (10 plots) were arranged in Completely Randomized Design (CRD) with three replications and their effect on Eri-silkworm performance assessed in terms of larval, cocoon, and post cocoon traits. Data were collected on growth attributes, leaf proximate analysis of cassava, eri-silkworms larval, and cocoon and post cocoon traits. Variety and nitrogen had variable in both laboratory and fields experiment including biochemical composition of leaves. Variety Kello was found to be superior compared to Qulle by revealing a silkworm rearing performance indicators of hatchability (90.23%), fecundity (366.2 eggs/female), shorter larval duration (18.46 days), better larval weight (6.27 gm), survival rate (92.66%), cocoon weight (3.44 gm), single shell weight (0.47 gm), pupal weight (2.96 gm) and effective rate of rearing (89%). Application of 160 kg N ha-1 gave highest hatchability (93.85%), fecundity (384.83 eggs per female), larval weight (6.5 gm), shell weight (0.51 gm), cocoon weight (3.66 gm), pupal weight (3.15 gm) and shortest larval duration (17.333 days). In terms of biochemical composition, kello leaves had higher moisture content (0.438%), ash (18.541%) and crude fat (16.69%). Higher crude fiber (16.248%) and total carbohydrate (27.234%) were obtained from Qulle variety. 160 kg N ha-1 gave the highest moisture (0.467%) and the lowest crude fiber (14.123% ). The highest leaf nitrogen content (4.802%) and crude protein (30.012%) was gained from the combination of kello and 160 kg N ha-1. In conclusion, variety Kello and 160 kg N ha-1 can be used for higher leaf yield, leaf quality and cocoon yield. Introduction In Ethiopia, agricultural production is of a subsistence nature. The agricultural production system is mainly rain fed and traditional, which is characterized by low input of improved seeds, fertilizer, pesticides and other technologies [1]. Poverty and increasing population pressure led to decline in land holding per household that eventually resulted in low level of production to meet even the consumption requirement of the households [2]. Poverty reduction and Increases in the unemployment rate due to increases in the population, therefore, requires income generation activities like mass rearing of silk producing organisms to obtain silk [3]. More than 85% of the Ethiopian population, which resides in the rural area, is engaged in agricultural production as a major means of livelihood [4]. The Ethiopian government’s development policy emphasizes agricultural sector development led industrialization. In 1996, the government initiated a food security strategy built around, increasing agricultural production at the household level, ensuring access to food for food deficit households, and strengthening institutional emergency response capabilities to achieve food security [5,6]. Sericulture provides gainful employment, economic development and improvement in the quality of life to the people in rural area and therefore it plays an important role to meet this policy. It provides employment at various levels [7]. In his review of sericulture Industry in India classified the employment generation pattern of the industry into two major types: (i) Direct Employment (a) Mulberry Cultivation; (b) Leaf Harvesting; (c) Silk Worm Rearing; (ii) Indirect Employment (a) Reeling; (b) Twisting; (c ) Weaving; (d) Printing & Dyeing; (e) Finishing; (f) Silk Waste Processing [8]; Sericulture is an agro-based industry. Sericulture provides economic development and improvement in the quality of life to the people in rural area and therefore it plays an important role in anti-poverty programme and prevents migration of rural people to urban area in search of employment. It can make employment up to 11 persons for every kilogram of raw silk produced; out of which more than 6 persons are women [9]. Estimated that one hectare of mulberry creates employment of 13-16 persons per year and their location specific analysis indicated that for a production of one kilogram of raw silk, 11 man days are required which can, in turn, employ 30 man days for production of silk fabric. Showed that 96.36 Derara Y1*, Sori W2, Nebiyu A2 and Mulat F3 1Department of Plant Sciences, Salale University, Ethiopia 2Department of Plant Sciences, Jimma University, Ethiopia 3Department of Plant Sciences, Mekdela University, Ethiopia Address for Correspondence Derara Y, 1Salale University, Department of Plant Sciences, P.O box 245, Salale, Ethiopia; E-mail: johnderara4@gmail.com Submission: November-26-2019 Accepted: January-02-2020 Published: January-04-2020 Copyright: © 2020 Derara Y, et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Journal of Plant Biology & Soil Health Avens Publishing Group Inviting Innovations Research Article Open Access J Plant Biol Soil Health January 2020 Vol.:6, Issue:2 © All rights are reserved by Derara Y, et al. Avens Publishing Group Inviting Innovations