276 
TABLE III: Seedling Progenies from Self- 
pollinated Normal Green Plants Heterozy- 
gous for Tall-dwarf and Green- 
Yellow Seedlings 
Pedigree Tall} Tall | Dwarf} Dwarf 
No. Green |Yellow | Green | Yellow 
3006 180 72 87 22 
3011 32 7 11 2 
Total 212 79 98 24 
Theoretical 232 78 78 26 
(9:3:3:1) 
Calculated 225 85 85 18 
on 1:1.4 
linkage 
of the theoretical on the basis of inde- 
pendent assortment. If this is a case 
of linkage, such a situation would be 
expected, since the tall and yellow 
characters came from one parent, while 
the dwarf and green characters entered 
from the other parent of the cross. 
If a linkage giving a gametic ratio 
of 1:1.4 is assumed, the calculated 
numbers agree more closely with the 
actual results. This indicates that 
the tall-yellow and dwarf-green gam- 
etes are produced approximately 1.4 
times more often than the tall-green 
and dwarf-yellow gametes. The num- 
bers are too small, however, for more 
than a suggestion of linkage. Further 
tests are being planned to determine 
this relation. 
It happens that the chlorophyll fac- 
tor involved in the dwarf-yellow cross 
is identical with the one in the dwarf- 
virescent-white cross discussed in the 
preceding section. In both cases it 
is the v factor (LLvv and llvv). 
In the dwarf-virescent-white cross 
there was no indication of linkage be- 
tween the chlorophyll factor v and the 
type of dwarf involved. In the dwarf- 
yellow cross however, there is a sugges- 
tion of a linkage between this same v 
and the semi-tall dwarf used there. 
This can only mean that the two sorts 
of dwarfs are genetically different and 
that their respective factors are located 
on different chromosomes. 
INHERITANCE OF ABORTIVE 
MAIZE 
In connection with the study of 
chlorophyll factors there occurred, 
GRAINS IN 
The Journal of Heredity 
among several self-pollinated ears of a 
certain cross, a single ear that showed 
an appreciable number of abortive 
grains. At first this was thought to 
be the result of poor pollen or imperfect 
pollination. But the recurrence of the 
phenomenon for two years dispelled 
this idea and suggested that some 
heritable factor was involved. 
Unfortunately no attempt was made 
in the earlier years to segregate and 
count the abortive grains. They were 
merely shelled off and planted with the 
normal grains. A marked deficiency 
in the percentage of germination was 
noted in these ears nevertheless. 
Last season, however, four self- 
pollinated ears and several crosses 
were produced. Three of the four 
selfed ears showed segregation into 
normal and abortive grains. The fourth 
was an entirely normal, well developed 
ear. Two ears (2208-4 and 2208-7) 
were photographed and appear in Fig. 
25 
The abortive grains are sharply dis- 
tinguishable from the normal ones. 
They possess no trace of an embryo 
and no endosperm tissue has developed ; 
they are merely shells made up of peri- 
carp tissue. Silks are nevertheless 
produced on them. The abortive grains 
are scattered more or less evenly over 
the entire ear. Their distribution and 
their proportion to the normal grains 
strongly indicates that they are in- 
herited as a simple Mendelian recessive 
character. 
Counts were made on the three ears 
and the number of normal and abor- 
tive grains on each are recorded in 
Table IV. 
TABLE IV: Showing Segregation into Normal 
and Abortive Grains of Three Self- 
pollinated Ears 
Pedigree Normal | Abortive| Dev 
No. Grains | Grains P. E. 
2208-1 229 86 1-.3 
2208-4 456 161 1.0 
2208-7 288 118 2.7 
Total 973 365 2.8 
Theoretical 1003 335 
(3:1) 
