Studies were conducted on the effect of PFI-1 and Kanmasi mulberry varieties of Morus alba L. on the larval growth, cocoon characters and larval and pupal mortality of 6 silkworm strains of Bombyx mori L. Silkworm strains fed on the PFI-1 mulberry variety showed an increment of 9.91% and 0.936% in larval and cocoon shell weight and 3.681 and 3.0 in percent shell ratio and good cocoons and a decrease of 9.4 and 7.6 in percent larval and pupal mortality than those fed on Kanmasi mulberry variety.

The PFI-1mulberry variety, being better in all performances, is recommended for rearing silkworm for better cocoon quality.