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Updated: June 27, 2025
Thus we have a very important result for the breeder, for it enables him to work to a definite aim and combine certain desirable characters into a single form. The term mutation, as already intimated, has been given to this process of producing new varieties in this way. The kinds so produced are termed mutants, and at first they were hailed by enthusiastic scientists as "elementary species."
Overworking and other conditions tending to produce large eggs and females also throw white mutants and show other signs of weakness. Old females lay larger eggs than do young ones. These eggs produce more females. They store more material, have a lower metabolism and less oxidizing capacity than do the earlier male-producing eggs.
Rubrinervis is a mutation from Lamarckiana, chiefly distinguished by red midribs in the leaves and red stripes on the sepals. When propagated from self-fertilised seed it produced about 95 per cent. of offspring with the same characters, and the remaining 5 per cent. mutants, one of which was laevifolia which had been found by De Vries among plants growing wild at Hilversum.
Starting from this conception the pedigree of our mutations must be considered as only one small group. Instead of figuring a fan of mutants for each year, we must condense all the succeeding swarms into one single fan, as might be done also for Draba verna and other polymorphous species.
Not caring to confess a lack of close observation, the number of mutants in such cases is usually kept secret. At least this statement has been made to me by some of the horticulturists at Erfurt, whom I visited some years ago in order to learn as much as possible about the methods of production of their novelties.
The recognition of useful new varieties being thus made easy, the whole attention of the breeder is reduced to isolating the seeds of the mutants that are to be saved and sown separately, and this process must be repeated during a few years, in order to produce the quantity of seed that is needed for a profitable introduction of the variety into commerce.
This conclusion was strengthened by the results of the next three generations, which were made on a much smaller scale and yielded the same, or at least the mutants most commonly seen in previous years. Instead of giving the figures for these last two years separately, I will now summarize my whole experiment in the form of a pedigree.
Of course there are, and always will be, marked variations, mutants, or 'sports, but, nevertheless, natural inheritance is the master key to the improvement of every form of life; and it is an encouraging fact that some of the states, as Indiana, for example, have already adopted laws looking toward the reduction of the reproduction of convicted degenerates."
Why had they been blind to this obvious danger? Fortunately the anger and terror were assuaged. Observers soon discovered the mutants were sterile, incapable of reproduction. More than that: though the new clumps spread and flourished and grew rapidly, they lacked the tenacity and stamina of the parent.
The first is that there shall be marked changes in the environment so that the process of natural selection has full opportunity to do its work. The second is that numerous new forms or mutants, as the biologists call them, shall be produced. Both of these conditions are most fully met in large continents in the temperate zone, for in such places climatic variations are most extreme.
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