柞蚕全茧量雌雄开差率的主-微位点组遗传分析

Genetic Analysis on Major-minor Locus Groups Controlling the Difference Rate of Female and Male Cocoon Weight in Antheraea pernyi

为探索柞蚕全茧量雌雄开差率的遗传特点,选择全茧量雌雄开差率有显著差异的5个柞蚕品种为亲本,按Griffing方法Ⅱ设计组配成15个双列杂交组合(10个杂交组合和5个亲本)进行完全双列杂交试验。应用数量性状主-微位点组分析法解析发现5个柞蚕亲本间的全茧量雌雄开差率由1个主位点组与微位点组控制,主位点组与微位点组的遗传率分别为37.18%和16.01%,主位点组的加性效应为-2.55%,显性效应为-3.43%。其中,亲本品种582的全茧量雌雄开差率最小,含有1个可以使全茧量雌雄开差率缩小的纯合加性(++)主位点组,杂交组合582×抗大的全茧量雌雄开差率最小,含有1个可以使全茧量雌雄开差率缩小的杂合显性(+-)主位点组。杂交组合全茧量雌雄开差率的遗传构成包括主位点组杂合显性效应或主位点组纯合加性效应、微位点组杂合显性效应和微位点组纯合加性效应,不同杂交组合上述3种效应所占的比率不同。亲本间全茧量雌雄开差率的主、微位点组及其遗传构成的解析,阐明了其杂交组合全茧量雌雄开差率的遗传特点,可作为柞蚕优良品种选育及杂交组合选配的理论依据。

To explore the genetic characteristic of difference rate of female and male cocoon weight in tussah silkworm, 5 varieties with significant difference in female and male cocoon weight were selected as parents to prepare 15 diallel cross combinations （including 10 F1 crosses and 5 parents） according to Griffing II pattern for conducting the complete diallel crossing tests. By employing major-minor locus group analysis for quantitative characters, the difference rate of fe- male and male cocoon weight between the 5 parental strains was found to be controlled by one major locus group plus minor locus groups. The heritability of major locus group and minor locus group were 37.18% and 16.01% respectively. The additive effect of major locus group and dominance effect was -2.55% and -3.43% respectively. Parent 582 had the lowest difference rate. It contained one homozygous additive （＋＋） major locus group which can narrow the difference rate of female and male cocoon weight. Its cross combination 582 x Kangda had the lowest difference rate of female and male cocoon weight, which contained one heterozygous dominance （＋-） major locus group. The genetic component ofcross combinations included heterozygous dominance effect of major locus group or homozygous additive effect of major locus group, heterozygous dominance effect of minor locus group, and homozygous additive effect of mi- nor locus group. The proportion of these three effects was different among different cross combinations. Our analysis on major-minor locus groups and their genetic componentthat control the difference rate of female and male cocoon weight between parental strains elucidated the genetic charac- teristics of the difference rate of female and male cocoon weight between various cross combinations, providing reference for selection and preparation of cross combinations in breeding excellent tussah silkworm varieties.