Identifying parents and generating hybrids with high combining ability for yielding fresh cocoon and raw silk in silkworm (Bombxy mori L.)

ABSTRACT This study was carried out to identify parents and hybrids by determination of general combining ability (GCA), specific combining ability (SCA), and heterosis in pure lines and their hybrids, which were selected from our gene sources, to determine new hybrid combinations that could be alternative or higher in yielding compared with M × N hybrid used in production. Combining ability and heterosis effects were studied for the eight quantitative characters through line × tester mating design. Chinese origin lines (KZ, ZF) were identified as females and Japanese origin lines (BR, ZB) as males, and by these, four hybrids were derived. M, N, and their hybrid were both used as control genotypes and to calculate the heterosis and commercial heterosis as well. All the genotypes were reared in standard conditions, in three replications. ZF (for pupa survival rate) and ZB (for hatching and filament length) presented significantly higher and positive GCA effects. In addition, ZB had negative GCA effect for infertile egg rate. Effects of SCA were not significant for all the characters. In conclusion, ZF × ZB hybrid could have a potential for the higher cocoon and silk production in Turkey.

摘要 本研究旨在通过对本课题组基因种质资源中筛选出的纯系及其杂交组合的一般配合力（general combining ability, GCA）、特殊配合力（specific combining ability, SCA）及杂种优势进行测定，以鉴定亲本与杂交种，并筛选出相较于当前生产中应用的M×N杂交种更具替代性或产量更高的新型杂交组合。本研究采用测交系交配设计（line × tester mating design），对8个数量性状的配合力及杂种优势效应展开分析。试验选用起源于中国的品系KZ、ZF作为母本，起源于日本的品系BR、ZB作为父本，由此配制得到4个杂交组合。以M、N及其杂交种作为对照基因型，同时用于计算杂种优势与商业杂种优势。所有供试材料均在标准饲养条件下培育，设置3次重复。结果表明，ZF在蛹成活率上表现出显著正向的一般配合力效应，ZB在孵化率及丝长上的一般配合力效应显著为正；此外，ZB的非受精卵率一般配合力效应为负值。所有供试性状的特殊配合力效应均未达到显著水平。综上，ZF×ZB杂交组合在土耳其具备提升蚕茧与蚕丝产量的应用潜力。