|
|
|
Mendel took also from pea
plants
|
|
of a pure-breeding line
producing
|
|
seeds that have a green
colour and
|
|
a wrinkled shape the
pollen to
|
|
fertilize plants of a
pure-breeding
|
|
line producing seeds
that have a
|
|
yellow colour and a
round shape
|
|
and vice versa.
|
|
|
|
Dihybrid crosses of:
|
 |
pollen
plant |
ab |
| green
seed |
a |
| wrinkled |
b |
| |
 |
seed
plant |
AB |
| Yellow
seed |
A |
| Round |
B |
|
|
and vice versa (seed
plant 'ab' and
|
|
pollen plant 'AB').
|
|
|
|
With the seeds gained
from these
|
|
hybrids Mendel raised a
next
|
|
generation of plants
together with
|
|
new plants of the
parental (AB and
|
|
ab) generation. Now he
fertilized:
|
|
1. three hybrids
with 'AB' pollen,
|
|
2. three hybrids
with 'ab' pollen,
|
|
3. three 'AB' with the
hybrids
|
|
pollen and 4. three
' ab' with the
|
|
hybrids pollen.
|
|
|
|
The forms that can be
expected are
|
| 1. |
AB |
ABb |
AaB |
AaBb |
| 2. |
AaBb |
AaB |
ABb |
ab |
| 3. |
AB |
ABb |
AaB |
AaBb |
| 4. |
AaBb |
AaB |
ABb |
ab |
|
|
In proofs 1. and 2.
especially the
|
|
nature of the hybrid
germ-cells
|
|
are tested, and in 3.
and 4. that of
|
|
the pollen cells.
|
|
|
|
Notwithstanding some
set-backs in
|
|
the cultivation Mendel
harvested
|
|
the following
quantities of seeds:
|
|
1. -- 98 only round
yellow seeds;
|
|
3. -- 94 only round
yellow seeds;
|
|
2. -- 31 round
yellow,
|
|
26 round green,
|
|
27 wrinkled yellow and
|
|
26 wrinkled green;
|
|
4. -- 24
round yellow,
|
|
25 round green,
|
|
22 wrinkled yellow and
|
|
27 wrinkled green.
|
|
The next year results
of the plants
|
|
from these seeds were:
|
|
1. -- 90 plants and 3.
-- 87 plants of
|
|
which in
|
| proof
1. |
proof
3. |
|
| 20 |
25 |
were
round yellow |
|
|
(AB), |
| 23 |
19 |
round
yellow and |
|
|
green
(ABb), |
| 25 |
22 |
round
and |
|
|
wrinkled
yellow |
|
|
(AaB), |
| 22 |
21 |
round
and |
|
|
wrinkled
yellow |
|
|
and
green (AaBb). |
|
|
In proof 2.and 4. the
round and
|
|
yellow seeds produced
plants with
|
|
round
and wrinkled
yellow and
|
|
green seeds (AaBb); the round
|
|
green seeds produced
plants with
|
|
round and wrinkled
green seeds
|
|
(Aab); the wrinkled
yellow seeds
|
|
produced plants with
wrinkled
|
|
yellow and green seeds
(aBb); and
|
|
the wrinkled green
seeds produced
|
|
plants that all had
again wrinkled
|
|
green seeds (ab).
|
|
In numbers were
produced so:
|
| proof
2. |
proof
4. |
|
| 31 |
24 |
(AaBb), |
| 26 |
25 |
(Aab), |
| 27 |
22 |
(aBb), |
| 26 |
27 |
(ab), |
|
|
|
which means that also
these forms
|
|
appeared in nearly the
same
|
|
quantities as expected.
|
|
|
|
Mendel experimented the
same
|
|
way also with the other
phenotypic
|
|
characters with of
course similar
|
|
results.
|
|
|
|
This way Mendel could
induce
|
|
experimentally the
thesis that
|
|
hybrids do form germ-
and pollen
|
|
cells which are related
according
|
|
their nature in equal
quantities to
|
|
all constant forms that
arise from
|
|
the combination of the
phenotypic
|
|
characters united by
fertilization.
|
|
|
|
This proofed thesis is
than also a
|
|
sufficient explanation
of the variety
|
|
of forms, and their
quantitative
|
|
relations, of the
offspring of the
|
|
hybrids.
|
|
|
|
|
