3. Differential dominance in number of kernel rows. - In the 1940 News Letter (14: 19-21), I reported differences in relative dominance of ten inbred lines of 12-row maize and of two 8-row inbred lines in crosses F3 and F4 cultures of the cross W-W × C-R of 12-row with 8-row lines. I now present further data on the crosses previously reported and tests of a few inbred lines not represented in the earlier report. The accompanying table includes the earlier as well as the later data.

Item
No.
Number of
cultures
Grade of
parent
Cob
color
Progenies Total Mean
grade
Pericarp-color grades
0 1 2 3 4 5 6
             
1 3 0 W 134 - - - - - - 134 0
2 2 0 R 116 - - - - - - 116 0
3 2 0 R 73 - - - - - - 73 0
4 1 0 R 51 4 - - - - - 55 0.1
5 1 0 R 32 6 - - - - - 38 0.2
      W 15 - - - - - - 15 0
6     R 2 10 - - - - - 12 0.8
      W 6 - - - - - - 6 0
7     W 13 19 6 1 - - - 39 0.9
8 1 2 W 6 8 16 12 - - - 42 1.8
      R 9 5 12 10 - - - 36 1.6
9 1 2 W 4 2 2 3 - - - 11 1.4
10 8 3 W 56 36 46 66 17 - - 221 1.8
11 1 3 R 2 1 2 3 13 5 - 26 3.5
      R 8 1 7 23 10 - - 49 2.5
12 2 3 W 9 2 3 6 2 - - 22 1.5
13 3 3 W - 14 17 29 8 - - 68 2.5
14 1 3 R - 6 16 13 11 - - 46 2.6
15 1 3 R - - 6 5 - - - 11 3.5
16 1 4 W 14 3 8 11 19 5 - 60 2.6
17 2 4 R 13 20 12 25 12 3 - 85 2.1
      R - 6 4 10 4 - - 24 2.5
18 1 4 W 10 - - - - - - 10 0
19 2 4 R - 6 9 19 29 9 - 67 3.6
20 1 4 R - - 3 21 12 1 - 37 3.3
21 4 4 W - - 7 76 70 2 - 155 3.4
22 2 4 R - - - 10 49 10 - 69 4.0
      W - - - 4 13 6 - 23 3.1
23 2 5 R 9 7 4 16 17 21 1 75 3.2
      W 7 2 4 8 2 - - 23 1.8
24 1 5 R - 2 8 9 16 8   43 3.5
25 1 5 R - - 2 3 7 6 - 18 3.9
26 1 5 R - - 1 10 12 9 - 32 3.9
      W - - 3 6 - - - 9 2.7
27 1 5 R - - - 1 8 16 - 25 4.6
      W - - - - 4 2 - 6 4.3
28 1 5 W - - - 3 12 5   20 4.1
29 3 5 R - - - 12 34 73 7 126 4.6
30 2 5 R - - - - 25 55 1 81 4.7
      R - - - 2 14 15 3 34 4.6
31 1 6 W - 1 2 6 - - - 9 2.6
32 1 6 R - - 1 3 9 34 12 59 4.9
33 2 6 R - - - - 12 42 33 87 5.2

 

Number of individuals and mean row number of F1 crosses
of 8-row with 12-row inbreds

12-row lines 8-row lines
1 51 Snf. W Y. Flr. Y. Flt. R. Flt.
             
VI  60- 8.9  54- 9.7           
IV  178- 9.1  72- 9.6           
III  75- 9.0  164-10.1           
VII  120- 9.2  91-10.1        194- 9.3  
2  346- 8.9  391-10.5  103-8.8  79- 8.8  114- 9.5  62-9.9
II  89- 9.7  129-10.1           
4  258- 9.4  177-10.6           
39  625- 9.6  716-11.4     213- 9.7     
G  93- 9.1  37-10.1  137-8.6  217- 9.4     
B  221- 9.1  284-10.5  144-9-0  151- 9.7  81- 9.5  
b  80- 9.8  58-10.4  78-9.2  87- 9.4     
c  91-10.5  88-11.1  76-9.6  81-10.3    
 
Averages of comparable means
    9.4  10.4           
    9.5  10.5  9.0        
    9.4  10.5     9.1     
    9.4  10.6        9.7  
    9.0  10.5           9.7
             

 

Key to line designations:

1. Luce's Favorite (Wiggans) VII. Early Pride
2. Onondaga White (Wiggans) R. Flt. Red Flint
4. Bloody Butcher (Wiggans) Snf. W. Sanford White
39. Golden Bantam (Purdue) Y. Flr. Yellow Flour
51. Golden Bantam (Purdue) Y. Flt. Yellow Flint
II. Westbranch B Segregates from crosses
of 8-row with
16-row lines
III. Queen's Golden G
IV. White Pop b
VI. Dutton's Flint c

 

Of the 8-row inbreds, Sanford White and Yellow Flour are somewhat more nearly dominant even than Luce's Favorite, while Yellow Flint and Red Flint are less nearly recessive than Golden Bantam. Similar differences are shown by different 12-row lines. Such differences are well illustrated by the following frequency distributions for number of kernel rows in crosses of two 12-row with two 8-row lines:-

 

Cross 8 10 12 14 Total Mean
 
1 with 2 199 144 3   346 8.9
1   39 151 437 37   625 9.6
51   2 61 183 145 2 391 10.5
51   39 13 196 497 10 716 11.4

 

That these differences in behavior are conditioned by gene differences rather than by cytoplasmic diversity is indicated by the fact that reciprocal crosses are essentially alike. The following data from reciprocal crosses are all that are now available:

 

Cross 8 10 12 14 Total Mean
 
2 × 1 69 58 2   129 9.0
1 × 2 79 55 1   135 8.8
 
39 × 1 65 227 19   311 9.7
1 × 39 70 187 10   267 9.6
 
39 × 51 9 135 371 5 520 11.4
51 × 39 3 32 67 3 105 11.3

 

It is not surprising that 12-row lines exhibit differences in relative dominance, because several of them at least are known to have different row-number genotypes. But 8-row types have been assumed to have the same genotype for number of kernel rows. Negative evidence in support of this notion is (1) Crosses of 8-row inbreds have not resulted, in my experience, in the production of other than 8-row types. (2) Crosses of 8-row with 12-row inbreds have not resulted in types with more than 12 kernel rows. It is, of course, conceivable that genes responsible for the 8-row condition may be alleles with the same effect on row number but with somewhat different dominance behavior.