[Fecundity improvement and cocoon character of silkworm (Bombyx mori L.) through estradiol-17 beta spraying to mulberry leaf]
2003
Arthadi((Universitas Jenderal Soedirman, Purwokerto (Indonesia). Fakultas Biologi))
It has been demonstrated that estradiol-17 beta improved fecundity and cocoon quality when injected to the fifth instar larvae of Bombyx mori at the laboratory level (Keshan and Ray, 1998). However, injection is not a practical way of applying estradiol-17 beta especially at industrial level. This research, thus, aims to investigate the efficacy of estradiol-17 beta if administered by spraying the hormone onto the mulberry leaves provided to B. mori larvae, and to investigate what instar is the most appropriate stage to be treated with the hormone to result in the best fecundity and cocoon quality. Using Completely Randomized Design, treatments with a dosage of 1 micron gram estradiol-17 beta/gr body weight were applied to 20 individual samples of instar 2, 3, 4 and 5 with 5 replicates. The results showed that application of estradiol-17 beta by spraying onto the mulberry leaves was significantly effective. In term of fecundity, application of estradiol-17 beta to the fifth instar resulted in the highest average number of eggs (617.4), followed by the fourth (580), third (564) and second (538.2) instars respectively compared to the control (506.6). Consistently, the best cocoon quality was resulted from the hormone treatment on the fifth instar with the average silk fiber length of 720.0 m followed by the fourth (667.0 m), third (630.8 m) and second (615.6 m) instars respectively. On the other hand, all estradiol-17 beta treatments reduced the cocoon ratio and reliability.
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