Study of thirty-one economically important traits in twenty silkworm <i>Bombyx mori</I> varieties

Abstract

The aim of this experiment was to study thirty-one economically important traits in twenty silkworm Bombyx mori breeds varieties. These varieties included 31, 1005, 113 (2029), 153 (Xihang-1), 5118 × 10133-3-3, F6 × 101, 1433-15, 1126 (111), 113-K, 1003-4, M2-6-18 (109), M2-6-22 (107), 151 (103 × M-1-1), Xihang 2/3, M-1-1 × 103, 7409, 107-K, 103, T5-M and 101433-1-4. Rearing of young silkworm instars was performed by feeding with chopped leaves and by using paraffin paper as a coverage while to the last instars, entire leaves and branches were administered. Rice straw was used as cocoon frames for spinning in each replication separately. Seven days after the starting of cocoon spinning, obtained cocoons were gathered and sorted on the basis of form, thickness, clarity, etc., into four classes including good, middle, double and low cocoons. The ratio of each cocoon class was calculated for each replication separately. The data obtained for different parameters were subjected to analysis of variance (ANOVA) to determine if the differences found among treatments were significant. Following ANOVA, Tukey’s studentized range test in a complete randomized design was used at p < 0.05. Obtained results showed that among studied varieties, the highest level of percentage of hatchability was observed in 107-K (97.77%), while 1003-4 variety (63.07%) remained at lower level than other varieties. Meanwhile, among studied varieties, the highest level of good cocoon number belonged to Xihang-1 (328.33), and 109 variety (159.67) remained at the lowest level with respect to other varieties (p < 0.05). Also, the highest level of good cocoon weight belonged to 1003-4 (341.83 g) and 7409 variety (194.09 g) remained at the lowest level in comparison to other varieties (p < 0.05). Finally, it is shown that the highest level of cocoon shell percentage belonged to 111 (1126) (23.11%) and 113-k variety (18.10%) remained at the lowest level as compared to other varieties (p < 0.05).

Keywords: Silkworm, performance, germplasm, cocoon, fecundity, disease