Comparative Study of The Biological Indics of the Pure Races and Hybrid Combinations Among Them at IVth and Vth Stage at the Silk-Worm (Bombyx Mori L.)

I. Pasca, A.L. Marghitas, Dana Pusta, R Morar, D., Dezmireanu, A., Cimpean, R., Oroian, T., Oroian, A., Macri, A., Lapusan, C. Jecan


The purpose of our study was oriented towards a comparative study of the biological characteristics of the larvae from parental breeds and the hybrid combinations during the IVth and Vth period at the silk-worm (Bombyx mori L.) taking into account the fact that there is a positive correlation in the development of the larva and the sericigene gland’s mass from which the silk thread results.
Analysing the obtained data, results the fact that the hybrids have a longer larva length and the multiplication rata higher starting from hatching until the last stadium of the larva, compared to the parental breeds. In what concerns the medium mass of the last aged larva and the multiplication mass rata of the hatching until the final larva stadium the differences were minimised, resulting the fact that the length of the larva does not influence the mass of the it. Therefore it is to be noticed the fact that the hybrids achieve superior performances in a three days shorter period.
The length of the larva stage in parental breeds being of 28 days while in the hybrid combinations the length of the larva stage was of 25 days, in this respect reducing the productive performances, the growth period, and the amount of food increasing at the same time


larvae; hybridisation; cross; voltinism; parental

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