家蚕限性黄茧品种与白茧品种组配四元杂交种研究

用改良成对家蚕限性黄茧品种 (中黄 B× 0 2、中黄 4×日黄 1)与现行强健、丝质优的成对白茧品种 (932× 75 32、芙蓉×湘晖 ) ,按现行四元杂交种的组配方式组配成四元杂交种 ,并进行饲养试验。结果表明 ,在正常季节 ,由 1对限性黄茧品种 (中黄 B× 0 2 )与 1对白茧品种 (“932× 75 32”或“芙蓉×湘晖”)组配成的四元杂交种 (“932 .中黄 B× 75 32 .0 2”或“芙蓉 .中黄 B×湘晖 .0 2”)与 2对白茧品种组配的四元杂交种“932 .芙蓉×75 32 .湘晖” (对照 )相比较 ,虫蛹率相似 ,万头产茧量增加 2 .2 2 %～ 4.2 8% ,万头茧层量增加 1.2 1%～ 3.86 %。白茧的一茧丝长、解舒率与对照相似 ,黄茧的一茧丝长 10 0 0 m左右 ,比对照短 10 0 m左右 ,解舒率比白茧差 2 0 %～ 30 %。说明成对限性黄茧种与成对白茧种组配的四元杂交种 (简称“2限黄 2白四元杂交种”)的综合经济性状可达到或超过现行实用四元白茧品种 (932 .芙蓉× 75 32 .湘晖 )的水平。“2限黄 2白四元杂交种”的杂交原种 8种组合中 ,有 4种组合 (即“限性黄茧 .白茧”)是雌茧黄色 ,雄茧白色 ,良种繁殖过程中利用这一特点鉴别雌雄工效比现行白茧品种提高 5倍左右 ,比斑纹限性品种提高 3倍左右 ,雌雄鉴别的准确率为 10 0 %。

Quaternary Hybrids between the Sex-limited Yellow Mulberry Silkworm Cocoons and the Commercial White Cocoons

The improved paired sex-limited yellow mulberry silkworm cocoon race (Zhonghuang B×02,Zhonghuang4×Rihuang1) and the strong commercial white cocoon race (932×7532,Furong×Xianghui) with high quality silk are hybridized in quaternary.The rearing experiment of the quaternaty hybrids is conducted.In normal season,there are similar larva-pura survival rates in both the quaternary hybrids(932·Zhonghuang B×7532·02 or Furong·Zhonghuang B×Xianghui·02) between one paired sex-limited yellow cocoon race(Zhonghuang B×02) and one paired white cocoon race(932×7532 or Furong×Xianghui) and the quaternary hybrids between two paired white cocoon races (932·Furong×7532·Xianghui) (as control);but the formers have 2.22% to 4.28% of increase of cocoon weight on per 10000 pupae,and 1.21% to 3.86% of increase of cocoon shell weight on per 10000 pupae. The length of filament,reelability rate of the white cocoons are similar to the control,but the length of filament of the yellow cocoons is about 1000 m,and about 100 m shorter than the control.The yellow cocoons are 20% to 30% lower than the white cocoon in reelability rate.It is suggested that the hybridization of the paired sex-limited yellow cocoons and the paired white cocoons could obtain the similar or better integrated economically characters than the commercial quaternary white cocoons such as 932·Furong×7532·Xianghui.It is found that the males are white and the females are yellow in the four out of eight hybrids between two sex-limited yollow cocoon races and two white cocoon races.In this way,it is easy and accurate to identify the gender of cocoons during rearing.The sexing efficiency for these quaternary hybrids is about 5-flod the commercial white coccons and about 3-fold the sex-limited marking races.