Buletin USAMV-CN, 63/2006 (125-129) ISSN 1454-2382 ASPECTS CONCERNING THE CORRELATION BETWEEN SOME BIOLOGICAL AND TECHNOLOGICAL TRAITS IN MULBERRY SILKWORM (Bombyx mori L.) Paşca, I., L.Al. Mărghitaş, R. Morar, Dana Pusta, Antonia Odagiu University of Agricultural Sciences and Veterinary Medicine Cluj – Napoca, Mănăştur St., No. 3 – 5, 400473 Cluj – Napoca, Romania, nicupasca@personal.ro Key words: digestibility, chrysalides, cocoon, incartment, fibroin Abstract: The identification of the mulberry silkworm breeds, which within optimal rearing conditions led to maximum performance with a minimum feed consumption, was the aim of our study. We recorded he coefficient of consumption and digestibility reported to the biological indices of the larvae. These traits were compared to the biological indices of both crude and dry cocoon. The results analyzes show no positive correlation between consumption and biological indices of the larvae (length, weight) and between the traits of the crude cocoon (weight of the crude cocoon, incartment, and silk percent) and indices of the dry cocoon (weight of the dry cocoon, wire length, wire weight, and fibroin content), except one breed (AC) which recorded the biggest values in majority of traits, less the coefficient of consumption and silk content. INTRODUCTION Obtaining a big production of dry cocoons with a highest silk percent, fiber weight and length is the aim of the intensive rearing of mulberry silkworms (Bombyx mori L.). The identification of the influence of the biological material, coefficient of consumption and digestibility, and larvae development within the same feeding, maintaining and microclimate conditions on these traits was the aim of our study. MATERIAL AND METHOD The biological material was made up of four mulberry silkworm breeds: China White (AC 29 ), Baneasa 1 (B 1 ), Cislau White (AC) Baneasa White (AB). Optimal microclimate conditions were supplied during entire period of the larvae stage, function of the larvae age. During growing stage, the light recorded variations between 15 lux in I st and II nd age, 10 lux in III rd and IV th age and 5 lux during V th age. The light intensity decreased during the last larvae stage due to the larvae sensitivity to light and their preparing for cocoon making. The thermic comfort of the silkworms depends on both temperature level and humidity from growing spaces. The temperature supplied during larvae stage recorded values between 26 – 27 0 C in I st age, 26 – 27 0 C in II nd age, 25 – 26 0 C in III rd age, 23 – 24 0 C in IV th age, 22 – 23 0 C in V th age and humidity recorded variations between 85% in I st age and 65 – 70% in V th age. The carbon dioxide recorded values under 0.003% during entire growing stage. The feeding (mulberry leafs – stain Ukraine 107) was administered at the same time intervals (4 hours), progressively function of age, smashed during first three ages, and whole during forth and fifth ages.