An Alternative
The homozygous recessive, white-glumed Chinese Spring
genetic stocks that were not nullisomic for Chromosome
I, but were nullisomic for some other chromosome that
does not carry the locus for glume color, segregated
3red:1white.
Nullisomic genetic stock for chromosome II that is
white glumed crossed to euploid Federation 41 that is
homozygous for red-glume color.
| |
male
21' haploid pollen |
| female
20' haploid egg |
F1
plant monosomic for chromosome II, but disomic for
chromosome I |
| |
male
R |
| female
r |
F1
plant Rr disomic for chromosome I |
F2 progeny from selfing monosomic F1 plant that
is disomic for chromosome I:
| |
male
R |
male
r |
| female
R |
RR |
Rr |
| female
r |
Rr |
rr |
F2 plants segregate 3:1 for glume color and all plants
are disomic for chromosome I.
Loci on non-homologous chromosomes segregate independently.
This is the reason why an F1 plant which is monosomic
for chromosome II will nevertheless segregate 3:1 for
a locus on chromosome I.
Data from Unrau(1950).
| Chromosome
tested |
red-
glumed |
segregating |
white
glumed |
x2
3:1 |
|
|
I |
528 |
0 |
38 |
100.93** |
| II |
637 |
0 |
193 |
1.35 |
| III |
628 |
0 |
219 |
0.33 |
| IV |
600 |
0 |
196 |
0.06 |
| V |
652 |
0 |
202 |
0.83 |
| VI |
748 |
0 |
228 |
1.45 |
| VII |
659 |
0 |
208 |
0.47 |
| VIII |
690 |
0 |
213 |
0.96 |
| IX |
248 |
0 |
73 |
0.87 |
| X |
797 |
0 |
248 |
0.89 |
| XI |
915 |
0 |
292 |
0.42 |
| XV |
708 |
0 |
224 |
0.47 |
| XVI |
814 |
0 |
264 |
0.15 |
| XVII |
1308 |
0 |
417 |
0.63 |
| XVIII |
578 |
0 |
174 |
1.39 |
| XIX |
679 |
0 |
212 |
0.69 |
XX
--------------
|
314
----------- |
0
-------------
|
99
---------- |
0.23
---------- |
|
The locus for red-glume color is located on chromosome
I.
