Leaf mineral composition of castor genotypes and its relationship with productivity of eri silkworms (Samia Cynthia ricini B.)
Kedir Shifa, Emana Getu, Waktole Sori
The growth, yield and reproduction potential of silkworms can be affected by their feed sources to a great extent. Minerals are among important biochemical components of leaves and they may have very big influence in productivity of silkworms. In the present study, eight different castor genotypes (Abaro, Acc 106584, Acc 203241, Acc 208624, Ar sel, Bako, GK sel and local genotype) were evaluated for their leaf mineral composition and effect on eri silkworms (Samia cynthia ricini B.) in Melkassa Agricultural Research Center (MARC), East- Shewa zone of Oromia Regional State, Ethiopia. Completely Randomized Design (CRD) with three replications was employed for carrying out feeding trial in a laboratory. The relationship of mineral components of leaves with silkworm parameters was also determined by using correlation coefficient analysis. Overall data Analysis was carried out by using SAS software at 5% probability level. Finally, the leaves of these genotypes showed significant differences among themselves in their mineral compositions. Their effect on rearing performance of eri silkworms was also statistically different when they were fed. Among castor genotypes tested, a genotype named Abaro found to be superior as compared to others by revealing a silkworm rearing performance indicators of 8.17 g matured larval weight, 3.344 g cocoon weight, 2.860 g pupal weight, 0.484 g shell weight and 14.487 % silk ratio, 74.68% effective rate of rearing (ERR), 76.079 % survival rate, 382.00 eggs as fecundity and 88.17 % hatchability of eggs. It was also found to constitute 4.125% nitrogen, 2.30% PPM phosphorus, 6874.5 PPM potassium, 102.033 PPM calcium and 13.467 PPM magnesium among foliar minerals. In addition, relationship of mineral constituents of castor genotypes with rearing performance of eri silkworms showed strong positive correlation of nitrogen and phosphorus contents with larval, cocoon and drainage parameters of eri silkworms. Therefore, it can be concluded that nitrogen and phosphorus contents of castor leaves will determine to the gains on important eri silkworm parameters when theses leaves served as feed sources. As a result, these minerals will be considered as basic parameters for evaluation of castor genotypes for eri silkworms rearing in the future.