Evaluation of Castor (Ricinus communis L.) Accessions as feed for Eri-Silkworm (Samia cynthia ricini Boisduval) larval performance and Cocoon Production at Jimma, South West Ethiopia

Abstract

In the development of sericulture, the quality of feed plays a remarkable role for growth and development of silkworms and ultimately on the economic traits of cocoons. The present study was undertaken to evaluate thirty two castor accessions for their leaf yielding performance and suitability as feed for eri-silkworm rearing at Eladale Research Station of Jimma University College of Agriculture and Veterinary Medicine, South West Ethiopia. Thirty two castor accessions were evaluated in randomized complete block design. Suitability of the castor accession as feed for eri-silkworms was evaluated in CRD under laboratory condition. Bothe experiments were replicated twice. Castor accessions showed significant variation both at field and laboratory experiment including biochemical composition of the leaves. Among castor accessions tested, Acc219668 registered 13890.9 kg/ha of fresh leaf yield. Higher disease severity (48.21%) was recorded on Acc219662/1. In terms of biochemical composition, higher nitrogen (3.90%) and protein (24.42%) was recorded from Acc219662/1 while high phosphorus (1.99%), fat (1.26%) and moisture (83.14%) content was recorded from Acc 200361and highest carbohydrate (52.15%) was recorded from Acc200355. However, high ash (22.9%) and fiber (24.01%) content were recorded from Acc 219647. Furthermore, significant and positive correlation coefficients were observed between erisilkworm traits and nitrogen, protein, moisture, phosphorus, fat and carbohydrate content of the leaves. On the other hand, negative association was observed among ash and fiber contents of the leaves and eri-silkworm traits except for larval duration. Moreover, in silkworm rearing performance shorter larval duration 17.5 days, higher larval weight 7.6gm and higher fecundity 351.45 eggs/female was noticed from Acc 200361 while higher hatchability (96.75%) recorded from Acc201067. In addition Eri-worms fed on leaves of Acc 200361 were found to be superior in terms of cocoon weight (3.55 gm), shell weight (0.51 gm), shell ratio(14.33%) and ERR (98.6%). Therefore, Acc 200361 which was comparatively the best in its agronomic performance and superior for all eri-silkworms traits was recommended for future research and development work. Future studies should conduct on these accessions to see their seed yielding performance and oil quality in relation to silkworm rearing. In addition, studies should be continue giving more emphasis to multi-location evaluation of this castor accession to understand how these accessions react to diverse growing areas.