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that close interbreeding lessens fertility, and, 1859 1860 1861
OMIT 1866 1869 1872

fertility, 1859 1860 1861
the vigour and fertility of the offspring, and on the other hand that very close interbreeding lessens their vigour and fertility, 1866 1869 1872

almost universal belief amongst breeders. 1859 1860 1861 1866 1869
conclusion. 1872

will 1859 1860 1861 1866 1869
if left to themselves, will 1872

be 1859 1860 1861 1872
have to be 1866 1869

their own individual pollen; and I am convinced that 1859 1860 1861
their own individual pollen; and 1866 1869
pollen from the same flower; and 1872

artificial 1859 1860 1861
the process of artificial 1866 1869 1872

may, 1859 1860 1861 1866
in contrast with those spontaneously self-fertilised, may, as 1869 1872

that close interbreeding lessens fertility, and, on the
one
other
hand
hand,
that an occasional cross with a distinct individual or variety increases fertility, that I
must admit
cannot doubt
the correctness of this almost universal belief amongst breeders. Hybrids are seldom raised by experimentalists in great numbers; and as the parent-species, or other allied hybrids, generally grow in the same garden, the visits of insects must be carefully prevented during the flowering
season;
season:
hence
hybrids,
hybrids
will generally be fertilised during each generation by their own individual pollen; and I am convinced that this would
probably be
be
injurious to their fertility, already lessened by their hybrid origin. I am strengthened in this conviction by a remarkable statement repeatedly made by Gärtner, namely, that if even the less fertile hybrids be artificially
fertilised
fertilised
with hybrid pollen of the same kind, their fertility, notwithstanding the frequent ill effects
from
of
manipulation, sometimes decidedly increases, and goes on increasing. Now, in artificial
fertilisation,
fertilisation
pollen is as often taken by chance (as I know from my own experience) from the anthers of another flower, as from the anthers of the flower itself which is to be fertilised; so that a cross between two flowers, though probably
often on
on
the same plant, would be thus effected. Moreover, whenever complicated experiments are in progress, so careful an observer as Gärtner would have castrated his hybrids, and this would have
ensured
insured
in each generation a cross with
a
the
the
pollen from a distinct flower, either from the same plant or from another plant of the same hybrid nature. And thus, the strange fact of
an
the
increase of fertility in the successive generations of artificially fertilised
hybrids,
hybrids
may,
as I
I
believe, be accounted for by
too close
close
inter-breeding
interbreeding
having been avoided.
Now let us turn to the results arrived at by
a
the
third most experienced hybridiser, namely, the Hon. and