... First Lessons in Poultry Keeping: Second Year Course... (Google eBook)

Front Cover
Farm-poultry Publishing Company, 1906 - Poultry - 160 pages
0 Reviews
  

What people are saying - Write a review

We haven't found any reviews in the usual places.

Common terms and phrases

Popular passages

Page 20 - In the case of each pair of characters there is thus one which in the first cross prevails to the exclusion of the other. This prevailing character Mendel calls the dominant character, the other being the recessive character.1 That the existence of such "dominant...
Page 21 - On the contrary the fifty cross-breds, as stated above, have mixed offspring. But these offspring, again, in their numerical proportions, follow the same law, namely, that there are three dominants to one recessive. The recessives are pure like those of the last generation, but the dominants can, by further self-fertilization, and examination or cultivation of the seeds produced, l>e again shown to be made up of pure dominants and cross-breds in the same proportion of one dominant to two cross-breds.
Page 21 - Hence it is seen that the 75 per cent dominants are not really of similar constitution, but consist of twenty-five which are pure dominants and fifty which are really crossbreds, though, like the crossbreds raised by crossing the two original varieties, they only exhibit the dominant character.
Page 20 - By letting the cross-breds fertilise themselves Mendel next raised another generation. In this generation were individuals which showed the dominant character, but also individuals which presented the recessive character. Such a fact also was known in a good many instances. But Mendel discovered that in this generation the numerical proportion of dominants to recessives is on an average of cases approximately constant, being in fact as three to one. With very considerable regularity these numbers...
Page 13 - This is the third step and the seventh mating in securing complete breeding of our new strain. ln all this we have not broken the line of sires, for every one has come from a group in which the preponderance of blood was that of the original sire. Nos. 2, 8, 13 and 18 are virtually the blood of No. 2. "We have reached a point where we may wish to establish a male line whose blood is virtually that of our original dam, and we now select from No.
Page 21 - The process of breaking up into the parent forms is thus continued in each successive generation, the same numerical law being followed so far as has yet been observed. Mendel made further experiments with...
Page 20 - This prevailing character Mendel calls the dominant character, the other being the recessive character." That the existence of such "dominant" and "recessive" characters is a frequent phenomenon in crossbreeding, is well known to all who have attended to these subjects. By letting the crossbreds fertilize themselves Mendel next raised another generation. In this generation were individuals which showed the dominant character, but also individuals which presented the recessive character. Such a fact...
Page 20 - Mendel discovered that in this generation the numerical proportion of dominants to recessives is on an average of cases approximately constant, being in fact as three to one. With very considerable regularity these numbers were approached in the case of each of his pairs of characters. There are thus in the first generation raised from the cross-breds 75 per cent. dominants and 25 per cent. recessives. These plants were again self-fertilised, and the offspring of each plant separately sown.
Page 20 - Length of stem, whether about (i or 7 feet long or about threefourths to 1 feet. Large numbers of crosses were made between pease differing in respect of one of each of these pairs of characters. It was found that in each case the offspring of the cross exhibited the character of one of the parents in almost undiminished intensity, and intermediates which "Comptcs Rendus, March 26, 1900, and Ber. il. Deutach. Bot. Gea, XVIII, 1900, p. 83. ''This conception of discontinuity !H, of course, pre-Mendelian....
Page 22 - ... there would be a very remote chance of such purity or fixity of type, whether of gamete or zygote. being detected. Dominance, as we have seen, is merely a phenomenon incidental to specific cases, between which no other common property has yet been perceived. In the phenomena of blended inheritance we clearly have no dominance. In the cases of alternative inheritance studied by Gallon and Pearson there is evidently no universal dominance.

Bibliographic information