Two local and important hybrids of silkworm, Bombyx mori L. were reared in three Egyptian governorates of Qalubyia, Giza and Sohag (Q, G and S). Fourteen parameters of 5^th instar duration (FD), whole larvae duration (LD), mortality percentage (MP), number of cocoon/liter (C /L), cocooning percentage (CP), duple cocooning percentage (DCP), cocoon crop by number (Crop/N), cocoon crop by weight (Crop/W) were recorded. Cocoon weight (CW), cocoon shell weight (CSW), pupae weight (PW), cocoon shell ratio (CSR), silk productivity (SP) for females and males were investigated. The results revealed that rearing silkworm was better in Qalubyia and Giza comparing with Sohag governorate. Some modifications for adjusting the rearing techniques, temperature and humidity to raise the silk production were recommended. As well as selections the hybrids suitable for Upper Egypt conditions.   
           Performances of hybrids characters are changed according to the environment changed.  The average of CW, CSW, PW, CSR and SP traits were better for both sexes in Qalubyia governorate. Hybrid of hy₁ was the best for CW, CSW, PW, CSR and SP traits for both sexes. Both of hy₁ and hy₂ were mostly the best hybrids in Qalubyia, Giza and Sohag of females and males. Evaluation index and subordinate function values depended on the hybrids which represented the genetic factor and the locations that represented the environmental factor and its interactions.