author(s)
SR Manjunatha, Manjunath Gowda, Nataraja Karaba, KC Narayanaswamy and KS Jagadish

abstract
Crop plants adaptable for water stress conditions are gaining importance due to scarcity of water resource, so as mulberry in sericulture potential areas. In this context newly evolved drought tolerant mulberry lines namely, VR, ST, BT, MT and RD have been developed and silkworm bioassay was conducted on these lines utilizing V instar silkworms of hybrid PM X CSR2 with V1 as a check (wild type), at the Department of Crop Physiology, UAS, GKVK, Bangalore, during June 2016. Fifth instar silkworms were reared on these mulberry lines and their influence on silkworm growth and few economic traits were assessed. The results revealed that these lines had no deleterious effects on silkworm growth and cocoon yield. The food consumption and food digestion of the silkworms were normal on all the transgenic mulberry lines and no significant differences were observed though wild type (V1) registered better values. Similarly, Effective rearing rate (ERR) calculated based on the V instar initial number and V instar larval weight were on par in all the lines tested. However, wild type fared better than the transgenic line (100% ERR and 39.19 g/10 larvae). Among the cocoon characters, cocoon yield by number, single cocoon weight and pupal weight were on par in all the lines, while cocoon yield by weight, single shell weight, shell ratio and silk productivity were significantly different and the wild type recorded higher values of 1817.25 g / 1000 worms, 0.36g, 19.26% and 5.21 cg/day, respectively. These findings suggest that drought tolerant transgenic mulberry lines have no adverse effect on silkworms and line ST performed better than other transgenic lines evaluated, being next only to wild type (V1).