Page:Mendel's principles of heredity; a defence.pdf/79

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In the tenth generation, for instance, 2ⁿ - 1 = 1023. There result, therefore, in each 2,048 plants which arise in this generation 1,023 with the constant dominant character, 1,023 with the recessive character, and only two hybrids.

The Offspring of Hybrids in witch Several Differentiating Characters are Associated.

In the experiments above described plants were used which differed only in one essential character[1]. The next task consisted in ascertaining whether the law of development discovered in these applied to cach pair of differentiating characters when several diverse characters are united in the hybrid by crossing. As regards the form of the hybrids in these cases, the experiments showed throughout that this invariably more nearly approaches to that one of the two parental plants which possesses the greater number of dominant characters. If, for instance, the seed plant has a short stem, terminal white flowers, and simply inflated pods; the pollen plant, on the other hand, a long stem, violet-red flowers distributed along the stem, and constricted pods; the hybrid resembles the seed parent only in the form of the pod; in the other characters it agrees with the pollen parent. Should one of the two parental types possess only dominant characters, then the hybrid is scarcely or not at all distinguishable from it.

  1. [This statement of Mendel's in the light of present knowledge is open to some misconception. Though his work makes it evident that such varieties may exist, it is very unlikely that Mendel could have had seven pairs of varieties such that the members of each pair differed from each other in only one considerable character (wesentliches Merkmal). The point is probably of little theoretical or practical consequence, but a rather heavy stress is thrown on "wesentlich."]