家蚕二化性杂交品种部分数量性状遗传参数的初步评估

采用完全随机设计法根据10头老熟幼虫体重、全茧重、茧层量、茧层率（%）、存活率、万蚕茧层量和茧丝长等指标，对两对二化性家蚕Bombyx mori L. 杂交品系（SH6×NB₄D₂和CSR₂×CSR₄）杂交一代的22个子代个体进行了遗传参数估算，以缩小优质蚕品种的候选范围，并且计算出直接筛选的参数，如遗传力和遗传进度等，使这些信息可用于以筛选高产新品种为目的的育种和选择过程中。杂交子代2, 4, 5, 6, 7, 10, 14, 16, 19和20号个体在这几个指标中表现出显著的优越性。全茧重、万蚕茧层量和茧丝长的遗传力和遗传进度较大，可以简单地从表现型的差异对这些性状进行选择并取得遗传性状改良。其他几个指标(10头老熟幼虫体重、茧层量、茧层率(%)和存活率)的遗传力和遗传进度较低，对这些性状进行直接选择来改良品种的效果较差。

Preliminary evaluation of some biparental progenies of two bivoltine silkworm (Bombyx mori L. ) hybrids

Twenty two BIPs (biparental progenies) generated from two bivoltine silkworm ( Bombyx mori L. ) hybrids, viz., SH6 × NB4D2 and CSR2 × CSR4, were evaluated for their performance in seven metric traits (weight of 10 mature larvae, single cocoon weight, single shell weight, shell ratio (%), effective rate of rearing, yield/10 000 larvae (wt.) and filament length.The experiment was laid out in a completely randomized design (CRD) with three replications for each treatment. The aim was to short list promising progenies and to work out estimates of direct selection parameters like heritability and genetic advance so that the generated information is utilized for the formulation of effective breeding and selection procedures aimed at extraction of new and more productive genotypes. BIPs 2, 4, 5, 6, 7, 10, 14, 16, 19 and 20 displayed a significantly superior performance in several traits. Single cocoon weight, yield/10 000 larvae (wt.) and filament length exhibited moderate estimates of heritability and reasonable genetic gains indicating genotypic variability to be a major component of phenotypic variability; hence, scope exists to bring about improvement in these traits through simple phenotypic selection. The rest traits (weight of 10 mature larvae,single shell weight, shell ratio (%) and ERR) recorded moderate estimates of heritability and low genetic gains environmental variability to be a major component of phenotypic variability; hence, selection for these traits would be less effective.