Leaf position of mulberry (Morus alba L.) affects silkworm growth, silk cocoon yield and quality

Mulberry plant (Morus alba L.) have long recognized as a main food plant for silkworm (Bombyx mori L.) worldwide, so the quality of mulberry leaves is essential factor for successful silkworm industry. This research examined the effects of mulberry leaf positions on yield and quality of silkworm cocoons. Leaf positions were ranked from shoot tip to base of the branch with youngest fully developed leaf ranked as + 1 leaf. Silkworms were fed by 4 respective mulberry leaf position treatments: T1—top leaves (from the + 2 to + 4 leaves); T2—middle leaves (from the + 5 to + 7 leaves); T3—basal leaves (from the + 8 to + 10 leaves), and T4—mixed leaves (mixture of all leaves). Here, we showed that silkworms fed by top leaves (T1) exhibited higher larvae weight, and produced higher cocoon weight, shell weight, and cocoon yield than those fed by other leaf position treatments. These results were attributed by the high moisture and protein content in tender leaves, which helped to increase the weight of larvae, leading to higher cocoon weight, shell weight, and cocoon yield. However, silk quality was found to be superior when larvae were fed with middle leaves (T2) due to high leaf dry weight and carbohydrate content. Consequently, middle leaves were recommended for achieving both optimal yield and quality of the silk cocoon.