NARAYANASWAMY, K. C.SREEJITH VAKAYIL2020-10-052020-10-052019-08-26https://krishikosh.egranth.ac.in/handle/1/5810152408The study on biochemical changes in thermotolerant bivoltine breeds during high temperature treatment and muscardine disease was conducted at the Department of Sericulture, UAS, GKVK, Bangalore using ten thermotolerant bivoltine breeds viz., B1 to B8, APS12 and APS45. The total protein content decreased from 24h pi to 120h pi in control and in worms exposed to high temperature, whereas in muscardine inoculation, it decreased from 24h pi to 72h pi and then increased at 120h pi. The total carbohydrates decreased from 24h pi to 72h pi and then increased at 120h pi, in control. The total carbohydrates in control was higher than other two treatments, except at 72h pi where muscardine treatment and high temperature treatment had higher carbohydrate content than the corresponding control. The total lipid content showed a decreased trend from 24h pi to 72h pi and then increased at 120h pi in control. The presence of 65kDa and 95kDa protein bands in B1, 80kDa and 70kDa protein bands in B2, 78kDa protein band in B5, 75kDa band in both B8 and APS45, recorded under both B. bassiana inoculation as well as high temperature treatment indicates that these proteins might be responsible for conferring dual stress tolerance. Larval and cocoon parameters suggested that B2 and B4 performed better for productivity characters while B1, APS12 and APS45 performed well for survival parameters under both muscardine disease as well as high temperature treatment. These breeds hold promise to further exploit their potential for evolving dual/ multiple stress tolerant silkworm breeds.EnglishThesis