The variability in cocoon shape is considered as an important parameter for evolving viable bivoltine silkworm hybrids of different crossing pattern and uniformity in cocoon shape helps in achieving improved reelability and uniform denier, the important post-cocoon quality parameters. In the present study, cocoon length, width, lengthwidth ratio, standard deviation and co-efficient of variation was assessed by utilizing the newly developed 21 each of different crosses of bivoltine hybrids (single, three- way and four- way crosses) along with control hybrids namely, (CSR2xCSR4) and [(CSR2xCSR27)x(CSR6xCSR26)]. The data revealed that wide variations in cocoon uniformity were observed among the different crosses of bivoltine hybrids. The study further revealed that the single-cross bivoltine hybrid, (CSR27xCSR26), three-way cross bivoltine hybrids, [(JPN8xCSR17)xD13] and [(D13xCSR26)xCSR17] and four-way cross hybrids [(JPN8xCSR17)x(D13xS9)] have recorded more cocoon uniformity.
Key words: Bivoltine hybrids, cocoon uniformity, single, three-way and four-way cross hybrids.
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