3. Tassel-seed 3 and tassel-seed 6 - The results of tests reported in the 1940 News Letter by Lindstrom and by me suggest that Ts3 is between an and gs, while Ts6 is near bm2 and probably to the right. The records reported by Lindstrom, tho conclusive in showing that Ts6 is near bm2, are inconclusive with respect to whether Ts6 is to the right or the left of bm2. Where one region is as long as that between br and bm2 and the other as short as bm2 to Ts6, double crossovers are apt to be as frequent as are singles in the short region. My last year's records, involving an and either gs or bm2 are unsatisfactory because of the wide differences between complementary classes of crossovers. The records presented here are equally unsatisfactory for the same reason. They are given first in a table as 4- and 5-point tests with complementary crossover classes combined.

 

Four- and five-point tests with Ts3 and Ts6
 
  + : br + : br + : br + : br + : br + : an
  + : f + : f + : f + : f + : f + : gs
Regions + : an + : an + : an + : an + : an Ts6 : +
  Ts3 : + Ts3 : + Ts3 : + + : gs Ts6 : + + : bm2
  + : gs + : bm2   Ts6 : + + : bm2  

 

0 88 68 104 82 26 152
1 4 7 11 6 2 56
2 21 15 22 32 12 35
3 21 14 19 35 22 11
4 33 30   31 1  
1-2   1 1 16
1-3   5   1
1-4   2   2  
2-3   5 3 3  
2-4 3 9   16  
3-4 16 5   19  
1-2-3   4  
1-2-4   1  
1-3-4   1  
2-3-4 2 1   1  
1-2-3-4  
Total 188 151 170 235 67 271

 

Percent Recombination
 
br-f 42.1   br-f 5.9   br-f 11.9   br-f 6.8   br-f 4.5   an-gs 26.9
br-an 16.0   br-an 22.5   br-an 22.9   br-an 28.1   br-an 25.4   an-Ts6 33.6
br-Ts3 34.6   br-Ts3 34.4   br-Ts3 33.0   br-gs 46.3   br-Ts6 53.7   an-bm2 38.0
br-gs 42.0   br-bm2 44.4   f-an 20.6   br-Ts6 45.5   br-bm2 55.2   gs-Ts6 19.2
f-an 13.9   f-an 16.6   f-Ts3 27.1   f-an 23.0   f-an 23.9   gs-bm2 22.9
f-Ts3 32.5   f-Ts3 28.5   an-Ts3 17.1   f-gs 46.8   f-Ts6 52.2   Ts6-bm2 4.4
f-gs 41.0   f-bm2 41.1   f-Ts6 45.5   f-bm2 53.7  
an-Ts3 20.8   an-Ts3 13.3   an-gs 27.2   an-Ts6 39.6  
an-gs 30.3   an-bm2 36.5   an-Ts6 39.6   an-bm2 38.8  
Ts3-gs 28.7   Ts3-bm2 31.2   gs-Ts6 30.2   bm2-Ts6 1.5  

 

The data, as presented in the accompanying table indicate that js3 is between an and gs, and Ts6 near bm2 and to its left. The unsatisfactory nature of the data is well shown when arranged as 2-point tests involving an and either js3 or Ts6, as follows:

 

+  Ts3
an  + 

 

  +Ts3 ++ anTs3 an+ Total
 
  64 39 0 85 188
  56 16 4 75 151
  63 25 4 78 170
   
Total 183 80 8 238 509

 

Total Ts3 = 191, non-Ts3 = 318
" an = 246, non-an = 263

 

+ Ts6

an  +

 

  +Ts6 ++ anTs6 an+ Total
 
  77 80 13 65 235
  24 16 9 18 67
  112 63 28 68 271
   
Total 213 159 50 151 573

 

Total Ts6 = 263, non-Ts6 = 310
" an = 201, non-an = 372

 

In the cultures involving Ts6, an was strikingly and Ts6 somewhat deficient. In the Ts3 cultures, an was slightly and Ts3 decidedly deficient. The striking feature of these records, however, is the discrepancy between complementary crossover classes, ++ to an Ts6 being over 3 to 1 and ++ to an 10 to 1.

It seems likely that some, perhaps many, plants recorded as +Ts6 may have been an Ts6. The tassels were not removed and in many cases, ears failed to develop, and it is difficult to determine an from the tassels alone of Ts6 plants. With a3 and an, experience of some years has led me to question whether there may be an inhibiting effect such that, when heterozygous Ts3 and homozygous an are together, both characters generally fail to develop. But no adequate test of such a notion has been attempted.