Breeding and the Mendelian discovery / by A.D. Darbishire ... with illustrations in colour and black-and-white.

  • Arthur Dukinfield Darbishire
Date:
1911
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Breeding and the Mendelian discovery / by A.D. Darbishire ... with illustrations in colour and black-and-white. Source: Wellcome Collection.

    164/370 page 102
    102 BREEDING 3. Green round — (i) Pure to colour and shape 1 (ii) Pure to colour but not to shape . 2 Pure to colour and shape 1 It will be observed that there is only one pure breeding representative of each of the four categories yellow round, yellow wrinkled, green round, and green wrinkled. The ratios in the above may be arrived at by multiplying together the ratios in which the parti¬ cular characters which make up each combination occur separately, having regard to the question whether the character is in a pure or hybrid state. Thus, when a yellow is crossed with a green the second hybrid generation is composed as follows : 1 pure yellow, 2 hybrid yellow, 1 green, in every four ; and the second hybrid generation from a cross between a round and a wrinkled has the following composition : 1 pure round, 2 hybrid round, 1 wrinkled, in every four, on the average. The com¬ bination of these six classes will, therefore, occur in the following ratios :— [1. Yellow round]— Pure yellow and pure round . 1x1 = 1 Pure yellow and hybrid round . 1x2 = 2 Hybrid yellow and pure round 2x1 = 2 Hybrid yellow and hybrid round 2x2 = 4
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