On The Inheritance Of Grey(dark) Plumage In Duck

Our studies on cross-breeding of Liancheng white duck×Baigai duck discovered that the down feather of many F₁ ducklings of is grey.So we supposed that the grey plumage of duck may be controlled by two loci gene.This study is based on generations of parents and F₁.Therefore,we designed nine test-groups of different genetypes to Observed the segregation ratio of different test-groups to check the judge.At the same time,we studied the relation between plumage color and some economy traits.The main results are as follows:1.Observing and recording the growth of down feather and the change of down feather color in different developing stages of ducking.Discovering that the plumage color of duckling(no white down feather) changed when the down feather sheded. Therefore,the analysis of plumage color on the basis of the down feather color may be wrong.The result of observing and recording showed that the earliest time to record the correct plumage color was after the sixth week.At that time the down feather had sheded.2.The genetic research of grey-dark plumage of duck.First,supposed that the grey(dark) plumage is controlled by two autosome genes(C and R);Then,we design some testing groups on the basis of parents and F₁ to check the suppose.The results showed that the segregation ratio of CcRr×CcRr was conformity to grey(dark): white=9:7(P＞0.60);the segregation ratio of ccRr×Ccrr was conformity to grey(dark): white=1:3(P＞0.50);the segregation ratio of ccRrxccRr was grey(dark):white=1:3(ratio of wrong was 0.5¹⁰=0.00098);the segregation ratio of CcRr×ccRr was conformity to grey(dark):white=3:5(P＞0.35);the segregation ratio of CcRr×Ccrr was conformity to grey(dark):white=3:5(P＞0.15);the segregation ratio of ccRR×CcRr was conformity to grey(dark):white=1:1(P＞0.45);the segregation ratio of ccRr×CcRr was conformity to grey(dark):white=3:5(P＞0.90);the segregation ratio of ccRr×Ccrr was conformity to grey(dark):white=1:3(P＞0.50);the segregation ratio of CcRr×CCrr was conformity to grey(dark):white=1:1(P＞0.55).Then the grey plumage of duck was controlled by two complementation loci genes.3.Discovering a new plumage color in F₂,it was dark plumage.The result of chisq-test of test-groups in which appeared dark duck showed that the segregation ratio of CcRr×CcRr was conformity to dark:grey:white=3:6:7(P＞0.85);the segregation ratio of CcRr×ccRr was conformity to dark:grey:white=1:2:5(P＞0.85);the segregation ratio of CcRr×Ccrr was conformity to dark:grey:white=1:2:5(P＞0.10);the segregation ratio of CcRrxccRR was conformity to dark:grey:white=1:1:2(P＞0.65);the segregation ratio of ccRrxCcRr was conformity to dark:grey:white=1:2:5(P＞0.95);the segregation ratio of CcRrxCcrr was conformity to dark:grey:white=1:1:2(P＞0.05).Then,one of the two loci genes had dose effect.4.The research of the relation between plumage color and economy traits.The analysis results of growth rate of different plumage colors showed that the early growth rate of white ducks was slower than grey(dark) ducks,but after six weeks,the difference disappeared gradually.The analysis results of abatage characters of different plumage color showed that it had no correlation between plumage color and abatage characters.