Stability of the crossbreeding effects obtainedby complete diallele design in silkworm(Bombyx mori L.)

摘要

Stability of crossbreeding effects in silkworm (Bombyx moriL.) was studied repeating a complete di allel cross over years. The examinedtraits were: raw cocoon weight in mg (RCW), cocoon shell weight in mg(CSW), length of the silk filament in m (LSF) and yield per one box of silk-worm eggs (Y/BE). Six lines were included in the study. Lines P14, P18 andP19 are of Chinese origin, monovoltine, with white cocoons. Lines P15,P16 and P17 were of Japanese origin, monovoltine, with white cocoons. Alllines were bred in the sericultural research station of the Agricultural Uni-versity, Plovdiv. Two basic models were applied for estimating heterosisand crossbreeding effects (Eisen et al., 1983; Griffing, 1956).In general, the estimates of the crossbreeding effects given by the model ofEisen et al., (1983) were confirmed by the results from the model ofGriffing (1956) (Tables 5 and 6). It gives highest estimates for the generalcombining ability of the lines P14 and P15. These results can be regarded to acertain extent as an approval of the Eisen's model estimates of direct, ma-ternal and heterosis effect of the lines. The estimates of the specific com-bining ability with the Griffing (1956) model are comparable for the perfor-mance of the crosses P14 x P18 and P17 x P19.