Varietal Traits
“Liangguang No. 2” (932•Furong × 7532•Xianghui) (reciprocal cross), with a “Chinese–Chinese × Japanese–Japanese” parentage, is a bivoltine, quadripodal, four-way hybrid. In the reciprocal cross, the eggs are brownish-green with a pale yellow chorion; in the reverse cross, the eggs are purplish-brown with a white chorion, and the newly hatched larvae are dark brown. Hatching is uniform, the larvae are robust, and the strain exhibits good adaptability to various leaf qualities. Molting at each instar occurs uniformly, and mature larvae have a bluish-white body color. Both reciprocal crosses produce white-bodied silkworms that are stocky and voracious feeders; mature larvae emerge uniformly; cocooning is rapid; cocoon shape is long-elliptical with a slightly tight crimp and relatively large size; cocoon color is white; shrinkage and wrinkling are moderate; and silk quality is excellent. The strain demonstrates tolerance to high temperature and high humidity, is not particularly demanding regarding leaf quality, and can withstand coarse feeding. However, in the reverse cross, when young larvae are reared on relatively tender mulberry leaves under elevated temperatures, it may induce the occurrence of third-instar dormancy (dormancy behavior being influenced by both genetic factors and environmental conditions). Cocoon shell percentage is around 21%, cocoon filament length is approximately 1,050 meters, reeled filament length is about 700 meters, cleanliness scores 93–94, and the resulting raw silk grade is below 4A.
Key Points of Husbandry Techniques
1. Brooding standards: For eggs in stages B2 to D2, maintain a temperature of 24–25°C under natural light; for eggs in stages D3 to F5, maintain a temperature of 25.5–26°C, with timely egg wrapping, complete darkness, delayed photoperiod exposure, and early collection of the hatched larvae to prevent dispersal of the young silkworms. The brooding period lasts approximately 11 days.
2. Temperature and humidity standards: During the young-caterpillar stage (1st–2nd instar), the temperature should be maintained at a slightly higher level of 28–29°C, with a dry–wet temperature difference of 0.5–1°C; during the mature-caterpillar and pupal stages, the temperature is best kept lower, at 26–27°C, with a dry–wet temperature difference of 2.5–3°C, and high temperatures above 30°C should be avoided.
3. On the day of egg collection and during the 1st–2nd instar, use mulberry leaves that are moderately mature and slightly tender; avoid overly mature leaves. For robust silkworms, use leaves that are fully mature; do not feed them young or contaminated leaves. Control the amount of mulberry leaves provided to prevent excessive leftover leaves, which can lead to a cold and damp rearing environment.
4. The silkworms are vigorous and begin feeding early; ensure timely feedings, achieve uniform maturity, and distribute the mature silkworms evenly when transferring them to the rearing racks.
Care Instructions
1. On the day of ant collection, photoperiod induction should not be initiated too early; rather, ant collection should be scheduled appropriately in advance. Before each mulberry-feeding session, thorough bed leveling and expansion must be carried out.
2. Young silkworms should be fed leaves at the optimal maturity stage, while mature silkworms exhibit vigorous feeding; ensure they are fully satiated.
3. During the fifth instar, when high temperatures and high humidity prevail, it is important to enhance ventilation and dehumidification.
4. Ensure uniform maturity of silkworms and prompt cocooning; promptly transfer mature silkworms to the rearing racks, maintaining a loose stocking density to minimize double-cocoon defects, and ensure adequate ventilation and moisture removal within the racks.
