The Effects of Cross & Self-Fertilisation in the Vegetable KingdomDarwin, Charles
Science
The Effects of Cross & Self-Fertilisation in the Vegetable Kingdom
Darwin, Charles
Fertilization of plants; Plants -- Variation; Pollination
CROSSED AND SELF-FERTILISED PLANTS OF THE SECOND GENERATION.
As in the last generation, many of the self-fertilised seeds germinated
before the crossed.
Seeds in an equal state of germination were planted on the opposite
sides of three pots. The crossed seedlings soon greatly exceeded in
height the self-fertilised. In Pot 1, when the tallest crossed plant was
10 1/2 inches high, the tallest self-fertilised was only 3 1/2 inches;
in Pot 2 the excess in height of the crossed was not quite so great. The
plants were treated as in the last generation, and when fully grown
measured as before. In Pot 3 both the crossed plants were killed at an
early age by some animal, so that the self-fertilised had no
competitors. Nevertheless these two self-fertilised plants were
measured, and are included in Table 6/77. The crossed plants flowered
long before their self-fertilised opponents in Pots 1 and 2, and before
those growing separately in Pot 3.
TABLE 6/77. Petunia violacea (Second generation).
Heights of plants measured in inches.
Column 1: Number (Name) of Pot.
Column 2: Crossed Plants.
Column 3: Self-fertilised Plants.
Pot 1 : 57 2/8 : 13 4/8.
Pot 1 : 36 2/8 : 8.
Pot 2 : 44 4/8 : 33 2/8.
Pot 2 : 24 : 28.
Pot 3 : 0 : 46 2/8.
Pot 3 : 0 : 28 4/8.
Total : 162.0 : 157.5.
The four crossed plants average 40.5, and the six self-fertilised 26.25
inches in height; or as 100 to 65. But this great inequality is in part
accidental, owing to some of the self-fertilised plants being very
short, and to one of the crossed being very tall.
Twelve flowers on these crossed plants were again crossed, and eleven
capsules were produced; of these, five were poor and six good; the
latter contained by weight 3.75 grains of seeds. Twelve flowers on the
self-fertilised plants were again fertilised with their own pollen and
produced no less than twelve capsules, and the six finest of these
contained by weight 2.57 grains of seeds. It should however be observed
that these latter capsules were produced by the plants in Pot 3, which
were not exposed to any competition. The seeds in the six fine crossed
capsules to those in the six finest self-fertilised capsules were in
weight as 100 to 68. From these seeds the plants of the next generation
were raised.
CROSSED AND SELF-FERTILISED PLANTS OF THE THIRD GENERATION.
TABLE 6/78. Petunia violacea (third generation; plants very young).
Heights of plants measured in inches.
Column 1: Number (Name) of Pot.
Column 2: Crossed Plants.
Column 3: Self-fertilised Plants.
Pot 1 : 1 4/8 : 5 6/8.
Pot 1 : 1 : 4 4/8.
Pot 2 : 5 7/8 : 8 3/8.
Pot 2 : 5 6/8 : 6 7/8.
Pot 3 : 4 : 5 5/8.
Pot 4 : 1 4/8 : 5 3/8.
Total : 19.63 : 36.50.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account