5^6 
Journal of Agricultural Research voi. xxvii, No. & 
The biometrical constants for the characters considered are given in 
Table VIII, and the frequency distributions are shown in figures 77-106. 
In each graph the shaded portion represents the plants classed as 
brachytic. 
CORRELATION OF THE BRACHYTIC VARIATION WITH CHARACTERS OF 
MAIZE 
When the biserial correlations with type of plant are examined it is 
found that there are 17 coefficients in excess of 3 times the error, while 13 
are below this figure (Table IX). Of the 17, height and total sucker 
height should be eliminated, since these obviously are but other measures 
of the brachytic nature of the plants. Of the 15 remaining coefficients, 
13 are coherences representing a tendency for the brachytic type of 
plant to reappear in the F 2 accompanied by other maize characters. 
The two disherences are the negative correlations of brachytic type 
with central spike index and with the number of leaves on the best 
inflorescence. Thus the brachytic plants, which usually have central 
spikes longer than those of normal maize plants and very much 
longer than those of teosinte plants, are found in this second generation 
to have relatively short central spikes. The coefficient, however, is 
only slightly in excess of 3.5 times the error, and may be due to chance. 
The negative correlation with the number of leaves on the best inflores¬ 
cence seems incapable of a logical explanation, and must stand as a definite 
disherence. 
Table VIII .—Biometrical constants for the second generation of the brachytic X teosinte 
hybrid • 
Entire population. 
Brachytic group. 
Normal group. 
! 
j Difference. 
Fig. 
Character. 
Mean. 
b 
w 
Mean. 
b 
w 
Pk 
Mean. 
b 
P. E. 
Amount. 
w 
Ph 
Amount. 
Pk 
num¬ 
ber 
of fre¬ 
quen¬ 
cy 
poly¬ 
gon. 
Height. 
22. 75 
6.94 
0. 278 
11. 74 
2. 71 
0.309 
24. 29 
5-89 
0.253 
12. 55 
0.399 
3i- 
48 
83 
Total sucker height.. 
7.04 
6. 50 
. 260 
1. 70 
1.35 
. 154 
7- 77 
6. 62 
. 278 
6.03 
.318 
18.95 
84 
Number of suckers.. 
3. 26 
2.49 
. IOO 
1.60 
I. IO 
. 125 
3- 49 
2. 54 
. 107 
1.89 
. 165 
11. 21 
85 
Diameter of culm.... 
Leaves above upper 
23.56 
424 
. 170 
27.91 
4- 33 
•494 
22. 96 
3- 87 
. 162 
"-4-95 
. 520 
9. 
52 
77 
branch. 
Total number of 
1. 73 
.86 
• 034 
1. 56 
.82 
. 098 
i- 75 
.87 
.037 
• 19 
. 105 
1. 
81 
82 
leaves. 
26.44 
3- 36 
• 134 
27. 06 
2. 82 
.327 
26.35 
3- 44 
. 148 
• 7i 
• 358 
1. 
98 
79 
Central spike index.. 
Length of branching 
58. 61 
7. 82 
.352 
55- 59 
931 
1. 108 
59- 14 
7- 38 
• 369 
3- 55 
1.167 
3- 
04 
78 
space. 
Length of central 
I2.‘59 
3-33 
. 140 
13 -03 
2.99 
•353 
12. 53 
3*37 
• 152 
1 
• 50 
• 384 
1. 
30 
86 
spike. 
Number of tassel 
17- 58 
4- 13 
. 186 
17. 09 
5-68 
.676 
17. 67 
3- 79 
. 1901 
.5® 
. 701 
83 
80 
branches . 
Length of longest 
34- 27 
li. 25 
.472 
36. 27 
1 
11.36 
1. 340 
33*97 
11. 22 
.505 
— 2. 30 
1.432 
1. 
61 
87 
tassel branch. 
Leaves above best in¬ 
24- 15 
5-34 
. 230 
24. 79 
6. 67 
• 787 
24. 05 
5- 07 
.233 
— ■ 74 
. 820 
92 
81 
florescence. 
Leaves on best in¬ 
2. 89 
1. 00 
. 043 
2. 81 
.92 
. 109 
2. 90 
1. 02 
• 0471 
. 09 
. 119 
75 
89 
florescence. 
Length of best in¬ 
4.38 
1. 15 
.049 
3- 74 
1. 02 
• 123 
4-47 
i- 15 
• °531 
• 73 
. 134 
5* 
45 
90 
florescence. 
Length of ear stalk of 
26. 53 
17. 15 
• 737 
ax. 34 
7. 08 
. 842 
27. 28 
18. 05 
.830 
5- 94 
1.182 
5- 
02 
88 
best inflorescence.. 
Length of 9 portion 
of best inflorescence 
Number of branches 
19- 38 
16. 00 
.688 
13- 23 
5- 96 
. 721 
20. 26 
16. 83 
• 774 
7- 03 
1.058 
6. 64 
92 
a. 75 
2. 94 
. 126 
4. 26 
3-32 
. 402 
2. 53 
2, 82 
. 130 
— i- 73 
■ 423 
4.09 
9i 
on best inflorescence 
2-43 
2 44 
• 105 
2. 03; 
2. 63 
.318 
2. 48 
2. 42 
. mi 
•45 
.336 
1. 
34 
93 
