author(s)
G Swathiga, G Umapathy, KT Parthiban and K Angappan

abstract
Ericulture is mainly confined to North-Eastern region of India. Eri Silkworm (Philosamia ricini) has several isolated populations, geographically separated (Eco races) in the states of Assam and Meghalaya. In the present study, different eco races of eri silkworm viz., Borduar, Barpathar, Khanapara, Mendipathar and Titabar were reared on five castor genotypes such as GCH 4, GCH 7, DCH 519, TMV 5 in comparison with local castor variety to record changes in the larval and cocoon parameters. The study revealed that, eri worms reared on the leaves of GCH 4 recorded significantly higher larval weight, larval duration, cocoon weight, cocoon yield, shell weight and shell ratio followed by DCH 519 and local castor variety. Among the eco-races, Borduar registered better in larval and cocoon parameters compared to other eco-races. The interaction between castor genotype x eri silkworm eco races, Borduar eco race of eri silkworm reared on the leaves of GCH 4 genotype found best for all parameters followed by GCH 4 x Titabar and the lowest was recorded in TMV 5 x Barpathar. It could be concluded that Borduar eco race of eri silkworm reared on GCH 4 castor genotype was found superior for the larval and cocoon parameters and same could be exploited for maximization of eri cocoon production.