RESEARCH CONCERNING THE ESTABLISHMENT OF THE BEST SIZE OF RACES POPULATIONS FROM THE GENE STOCK SP. BOMBYX MORI L.

Alexandra Matei, M. Androne, A. Popescu, D. Dezmirean, B. Vlaic

Abstract
The present technique utilized in sericultural genetic resources conservation, provides "in situ" silkworm conservation with the maintenance of small effectives as part of races using the selection based on mainly qualitative criteria (layings aspect and colour, larvae colour, cocoon shape and colour). Paper's aim is establishing the best size of gene stock populations based on quantitative parameters achieved in the conditions of different populations size, and on the other hand the estimation of an actual population size taking as criteria the increase of consanguinization by generation and the real number of males and females. As biological material 6 silkworm races were used: AC 29/T, AB, B1, AC/T, RG 90 si IBV. Adult free pairing was practiced. In the case of populations small actual size utilization, small values of quantitative parameters, conglomerate layings deposit, appearance of malformations at adults, are achieved. Minimum actual size of populations gene stock that allows a distant consanguinization (Df=0.50%) is of 100 individuals (50 females +50 males).

Key words: Bombyx mori L., population size, prolificacy, silk cocoons

CERCETARI PRIVIND STABILIREA MARIMII OPTIME A POPULATIILOR LA RASELE DIN REZERVA DE GENE SP. BOMBYX MORI L.

Alexandra Matei, M. Androne, A. Popescu, D. Dezmirean, B. Vlaic

Rezumat
Tehnica actuala utilizata in conservarea resurselor genetice sericicole prevede conservarea "in situ" a raselor de viermi de matase cu mentinerea unor efective mici in cadrul raselor si cu practicarea selectiei pe criterii mai mult calitative (aspectul si culoarea pontelor, culoarea larvelor, forma si culoarea gogosilor). Scopul lucrarii il constituie stabilirea unei marimi optime a populatiilor rezerve de gene pe baza parametrilor cantitativi realizati in conditiile unor marimi diferite ale populatiilor, iar pe de alta parte estimarea marimii efective a populatiei luand drept criteriu cresterea coeficientului de consangvinizare pe generatie si numarul real de masculi si femele. Ca material biologic s-au folosit 6 rase de viermi de matase: AC 29/T, AB, B1, AC/T, RG 90 si IBV. S-a practicat imperecherea libera a adultilor. In cazul utilizarii unor marimi efective mici a populatiilor (Ne=5-20) se obtin valori mici ale parametrilor cantitativi, depunere de ponte conglomerate, aparitia de malformatii la adulti. Marimea efectiva minima a populatiilor rezerva de gene care sa permita o consangvinizare indepartata (Df=0.50%) este de 100 indivizi (50 femele+50 masculi).

Cuvinte cheie: Bombyx mori L., marimea populatiei, prolificitate, gogosi de matase