莆田黑鸭青壳蛋遗传规律的研究

Study on Genotype of Blue Egg Shell in Pu-tian Black Laying Ducks

应用近交系数为12.5—25%的产青壳蛋的M和R家系与产白壳蛋N家系测交,获得产青壳蛋纯合型A和杂合型B.A型与N系杂交,其F_1全同胞女儿鸭全部产青壳蛋.B型与N系杂交的F_1有产青壳和白壳蛋.A型与N家系交配的后代(F_1)与N家系回交,产生的F_2产青、白壳蛋比率为1:l;A型与N家系交配的后代(F_1)自交,产生的F_2母鸭产青、白壳蛋的比率为3:1;A型自交及其后裔与N家系回交的母鸭全部产青壳蛋.上述的结果均符合质量性状的遗传规律,说明莆田黑鸭蛋壳色是由显性青壳蛋基因和隐性白壳蛋基因所控制,青壳对白壳为显性.

With coefficient of inbreeding being 12.5-25% , the M and R line duck which lay blue shelled egg was applied to test-cross with egg shell N line. As a result, both blue egg shell homotype A and heterotype B have been obtained. While crossing A type with N line, all their full F1 duck laid blue egg. According to probability analysis and principle of qualitative character determination, it is of 95 - 99% reliability for A type parents possessing homozygotle of dominant blue shell. Crossing B type with N line, full F1 duck laid both white and blue egg, so B type is a dominant heterozygote in terms of the mentioned principle above. Moreover, F1 from A cross N line was carried out back-cross with N line, the ratio of blue to white shell in F2 egg was 1:1, as self-crossing among F1 which become 3:1. And all full duck bred from either selfed A type or back cross between A selfed progeny and N line laid entirely blue egg. All the results mentioned above conform to the genetic law of qualitative character and elucidate that egg shell colour of Putian black duck is controlled by alleles with dominant blue and recessive white, therefore, blue shell dominanted over the white one.