Abstract
Flacherie virus (FV) is an important pathogen in the silkworm, which often gives serious damage to farmers for cocoon production. The inbred parents and F$_1$'s from an eight-parent diallel were examined to determine the inheritance of resistance to flacherie virus in the silkworm. Three resistant (R), two intermediate (M) and three susceptible (S) inbreds were used in the diallel with no reciprocals. Mean resistance was measured by survival rates of larvae which were fed on mulberry leaves sprayed with diluted mid-gut homogenate of FV infected larvae. Broad-sense heritability was obtained according to inbreds and F$_1$ family performance. Estimation of general (GCA) and specific combining ability (SCA) was made according to Griffing's Model 1, Method 2. Mean FV resistance of F$_1$ family displayed additive effect of the major gene, while heterotic effect was not significant. Considerable variation in FV resistance within F$_1$ groups of R$\times$S and S$\times$S indicated that action of minor genes for FV resistance may have been involved. FV resistance of inbreds perse and predominant effect of the major gene over minor gene(s) satisfactorily predicted the FV resistance of the hybrids. Broadsense heritability value of FV resistance on the basis of F$_1$ family performance averaged 93%, which suggested that environmental effects might have not been important in this experiment. GCA was highly significant for FV resistant among inbreds. GCA effect of 13.1 in Jam 108 was highest and -17.7 in Gyeongchu lowest. Effective selection for high FV resistance would be possible, using inbreds with high GCA effect and low GCA variance. SCA was significant among hybrids. High SCA effect in the hybrid of Geumho$\times$Mudeung (13.7) and Hansaeng #4$\times$Jam 115 (11.6) indicated that the interaction effect of minor genes for resistance to FV in the silkworm could be exploited by standard silkworm breeding procedures.
가잠의 바이러스성 연화병에 대한 저항성의 유전양식을 구명하기 위한 시험을 실시하여 다음과 같은 결과를 얻었다. 1. 유전력 검정 1) FV저항성의 주동인자는 불완전 우성에 의한 상가적효과를 보였다. 2) 미동인자의 효과는 특히 저항성이 강한 계통과 약한 계통과의 교배조에서 나타났다. 3) 유전력은 0.93으로서 거의 유전적 요인에 의한것이며 환경변이는 적다고 생각된다. 2. 원종간의 조합능력 검정 1) 일반조합능력효과는 고도의 유의차가 있었으며, 잠 108이 13.1로 가장 높았고 경추가 -17.7로 가장 낮았다. 2) 특수조합능력효과도 고도의 유의차가 있었으며, 금호$\times$무등에서 13.7로 가장 높았고 잠115$\times$경추에서 -14.8로 가장 낮았다.