摘要
蚕品种夏芳的卵色为黑褐带绿色 ,卵壳为淡黄色。在应用中出现了卵色不纯 ,区间和区内卵色驳杂。区间差异 ,其代表型变异卵色为棕褐色 ,蛾区内较一致 ;区内有差异者主要表现为正常型与果绿色的深浅对比 ,其中多数是后产下卵的内环少部分卵粒颜色浅 ,也有随机分布者。经采用后代鉴定法和杂交试验研究 ,结果 :①同蛾区内卵色的深、浅对比差异在后代没有明显的遗传趋向 ,并非单一的卵色遗传因素引起 ;②代表型变异卵色———棕褐色由隐性基因控制 ,表现母性遗传 ,并区别于家蚕的其它母性遗传卵色 ,可能为一新的家蚕母性遗传卵色基因。此外 ,滞育性较弱容易产生生种 ,也是导致夏芳在整体上卵色驳杂表现的一个因素。提出淘汰变异卵、纯化品种性状的方案为 :①直接在母种中选除具有变异卵的蛾区 ;②对表型为标准性状的母种蛾区 ,在蛾区半保留条件下 ,用同蛾区交配法进行后代鉴定 ,或测交法结合次代鉴定进行区别 ,以基因型为 + /+的半蛾保种或繁育原种 ,淘汰基因型为 + /b及b/b的蛾区。同时 ,注意综合选择 ,加强催青温度控制和饲养规范等技术措施。
The silkworm race 'Xiafang' is characterized by greenish dark brown egg and light yellow egg shell. Impurity occurs in commercial production and mosaic colors appear in eggs between or within egg batches. For inter-batch differences, the typical variation in egg color is tannish brown with fairly uniform tint within the batch. Intra-batch differences manifest themselves in the contrast between the different shades of green, usually with lighter color for the eggs laid later, and random distribution may also be possible. Offspring identification and hybridization experiments show that the contrast of light and dark color of eggs within the batch is not caused by a single factor for it does not show a distinct tendency in inheritance and that the typical variation in egg color, i.e. tannish brown egg, is controlled by a recessive gene and characterized by maternal inheritance. This recessive gene seems to be a new gene of egg color of maternal inheritance as it is distinguishable from other known genes of maternal inheritance. In addition, another factor that has resulted in the mosaic color of eggs in Xiafang may be the fact that this race is weak in diapause. Two approaches are recommended in this paper to eliminate the variant eggs and purify the race: a ) Directly eliminate the batches with variant eggs; b ) Reserve half of the batches with standard phenotypic characters, and make offspring identification with intra-batch mating or make test crosses in combination with identification of the next generation. In this way, the original race is maintained or multiplied with the half batches of the genotype +/+, and the batches with a genotype of +/b or b/b are eliminated.
出处
《蚕学通讯》
2002年第4期7-13,共7页
Newsletter of Sericultural Science
基金
四川省蚕种管理总站立项资助
关键词
卵色变异
遗传特性
选择方法
夏芳品种
家蚕
silkworm race variant in egg color inheritance selection method
