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对现行家蚕品种进行遗传改良获得新的家蚕性连锁平衡致死系,是快速育成优良雄蚕品种的技术途径之一.建立了一种将性连锁平衡致死系限性卵色和致死基因导入现行家蚕品种的方法:通过雌回交把家蚕性连锁平衡致死系用于原种雌雄鉴别的限性卵色基因w3和控制一代杂交组合性比的2对隐性胚胎期致死基因l1、l2导入现行优良家蚕品种,即用现行品种的雌性与性连锁平衡致死系的雄性杂交,再用性连锁平衡致死系的雌性与杂交后代回交,以后多次用现行品种的雌性回交,再多代自交固定后育成具有现行品种优良经济性状的性连锁平衡致死系.采用该方法,将性连锁平衡致死系的限性卵色基因与胚胎期致死基因导入现行优良家蚕品种云蚕8A和云蚕8B中,并按云蚕7×云蚕8的组配方式配制雄蚕一代杂交组合,其雄蚕率达100％,与原杂交组合相比,虫蛹率、解舒率、干茧出丝率分别提高2.33、5.53、2.60个百分点,茧丝洁净达95.4分,表明该方法可用于创制经济性状优良的家蚕性连锁平衡致死系育种材料.“,”To breed new sex-linked balanced lethal silkworm (Bombyx mori) strain by genetic improvement on current silkworm variety is a fast way to obtain the excellent male silkworm variety.In this study,a new method was established for introducing the sex-limited egg color gene and balanced lethal genes into current silkworm variety.Egg color gene W3,and two recessive embryonic lethal gene l1 and l2 were introduced into current variety by means of female backcrossing.That is,female silkworm moths of current variety were used to hybrid with male moths of the sex-linked balanced lethal silkworm line,then the females of the sex-linked balanced lethal silkworm line were used to backcross with the above-obtained hybrids,and the filial generations were backcrossed repeatedly using females of current silkworm varieties.Finally,the new sex-linked balanced lethal silkworm strain with most traits of the current silkworm variety was obtained by multi-generations of self-bred.Thus,the sex-limited egg color gene and balanced lethal genes were successfully introduced into the current silkworm varieties Yuncan 8A and Yuncan 8B with excellent economic traits by this method.A male silkworm hybridized combination was prepared using the crossing mode of Yuncan 7 × Yuncan 8,in which 100％ male silkworm were achieved.Compared with the original hybrid combination,pupation rate,reelability and raw silk rate of dry cocoon of the new hybrid combination was increased by 2.33,5.53,2.60 percentage points respectively,and cleanness score was up to 95.4 points.These results indicate that the established method can be applied to create excellent breeding materials with sex-linked balanced lethal property.