夏秋用家蚕品种7个数量性状的配合力与遗传力分析

采用8×8不完全双列杂交法(NC )Ⅱ,对来自不同生态区域的8个中系与8个日系夏秋用家蚕品种及其相应的64个杂交组合的全茧量、茧层量、茧层率、万蚕产茧量、万蚕茧层量、死笼率、虫蛹统一生命率等7个主要数量性状进行配合力与遗传力分析.结果表明:7个数量性状的一般配合力(GCA)和特殊配合力(SCA)方差达到了显著水平或极显著水平,它们的遗传由加性效应与非加性效应共同控制,但主要以加性效应为主;死笼率、虫蛹统一生命率、万蚕收茧量易受环境因素影响,全茧量、茧层量、茧层率、万蚕茧层量主要受遗传因素控制;茧层率、茧层量与全茧量属于遗传力高的性状,它们可在早期世代进行定向选择,死笼率、虫蛹统一生命率则因其遗传力低,宜在前期选择的基础上在中后期进一步加大选择压;中系品种C5与日系品种日3有较高的一般配合力效应,其组合日3×C5的特殊配合力效应也较高,是家蚕育种中理想的亲本材料

Combining Ability and Heritability Analyses of Several Quantitative Characters in Different Summer-autumn Varieties of Silkworm, Bombyx mori

The combining ability and heritability of eight Chinese and eight Japanese summer-autumn rearing silkworm varieties from different ecotopes and their 64 cross combinations were analyzed in an 8×8 incomplete diallel crossing design(NCⅡ) for the following seven quantitative characters: cocoon weight,cocoon shell weight,cocoon shell ratio,cocoon crop per 10 000 4th larvae,shell weight per 10 000 4th larvae,dead worm cocoon rate and larva-pupa viability rate.The results showed that variances of the general combining abilities(GCA) and special combining abilities(SCA) of the seven quantitative characters were significant or greatly significant,and all of these characters were controlled by both additive and non-additive effects with the additive effect the principal one.Dead worm cocoon rate,larva-pupa rate and cocoon crop per 10 000 4th larvae were mainly affected by environment factors,whereas the remaining quantitative characters were mainly influenced by genetic effects.Cocoon shell ratio,cocoon shell weight and cocoon weight were the characters with high heritability,and the directional selections for them could be conducted in earlier selections.In contrast,it was better to increase selection pressures in the middle and late selection periods for dead worm cocoon rate and larva-pupa rate because of their low heritabilities.Chinese variety C5 and Japanese variety Ri3 showed high GCA effects,and the combination Ri3×C5 showed high SCA effect,indicating varieties C5 and Ri3 were superior parent materials which would be used in future breeding programs.