Abstract:
In a study undertaken to evaluate the region and season specific multi x bi
and bivoltine hybrids of silkworm Bombyx mori, for commercial exploitation in
Kerala, six hybrids of silkworm were reared using K-2 and S-36 mulberry varieties
under Vellanikkara condition. The crosses used were PM x NB18, PM X NB4D2 and
their reciprocals, NB4D2 x NB18 and its reciprocal and PM as check.
The evaluation was carried out based on characters like leaf consumption,
larval duration and weight, cocoon and shell weights, shell ratio percentage, average
filament length, denier, reelability and renditta. The climatic factors were also
correlated with major economic characters of silkworm.
The present study confirms the superiority of bivoItine silkworm hybrids
like NB4D2 x NBI8 and NB18 x NB4D2 justifying their wide acceptance in states
other than Kerala. It is evident that if rearing is done in a systematic way, by strictly
adhering to the brushing period in correlation with the seasons and if the use of high
quality mulberry varieties is advocated these crosses will yield good returns in
Veil ani kkara.
Though the various economic parameters reflected a variable trend,
ultimately when the average filament length/g cocoon, shell ratio percentage and
cocoon weight were considered, the bivoltine hybrids performed superior to the
others.
