Evaluation of promising castor genotype in terms of agronomical and yield attributing traits, biochemical properties and rearing performance of eri silkworm, Samia ricini (Donovan)

Castor (Ricinus communis L.) is an economically important plant for production of industrial oil as well as used as primary food plant for rearing of eri silkworm, Samia ricini (Donovan). The biomass yield of eight selected castor accessions were studied to find out a promising castor genotype in terms of growth and biomass yield, nutrient status, disease and pest resistant together with eri silkworm rearing performance. Among the selected accessions, Ac03 and Ac04 yielded an average of 344.70 g (±88.05) and 334.50 g (±60.62) of leaf biomass/plant respectively (mean 324.62 g; n = 8) and the yield was stable over the years (2007-10). However, in late winter, leaf blight and leaf spot disease were reported in all the castor accessions together with the infestation of hairy caterpillar (4.00-5.33%). The silkworm rearing performances were also better in Ac03 in terms of shell weight (0.50 ± 0.07 g; mean 0.42 g; n = 8), shell ratio (15.5%) and effective rate of rearing i.e. ERR (85.67). ERR of eri silkworm was influenced by biochemical compositions of leaves of different castor accessions. The weight of larvae and cocoons were significantly influenced by nitrogen and crude protein content of the foliages. Altogether, Ac03 and Ac04 castor genotypes were found to be better in terms of agronomical and yield attributing traits together with silkworm rearing performance.