2. Linkage data involving an and Ts3 or Ts6 - Striking differences between complementary crossover classes were reported by Emerson 1941 News Letter (p. 13-15). Those records may not have been wholly accurate for the following reason. Some of the Ts plants failed to develop ears since the tassels were not removed at the time of emergence. Classification of an from the tassel when combined with Ts is difficult. Therefore, similar progenies were repeated this summer and the classification of an based on the ear.

+ Ts3/an + + Ts3 ++ an Ts3 an +
1941, tassels removed 174 109 5 288
1940, tassels not removed 183 80 8 238
 
+ Ts6/an + + Ts6 ++ an Ts6 an +
1941, tassels removed 75 36 17 67
1940, tassels not removed 213 159 50 151

The results of both plantings are essentially alike. One may conclude that the unequal nature of the complementary crossover classes is not primarily due to inaccuracies of classification but rather to some other cause.

Using the totals of both seasons, the following ratios occur:

Ts3 cultures
 
370 Ts3 : 715 + D/PE = .9 for 1:2 ratio
546 + : 539 an D/PE = .4 for 1:1 ratio
 
355 Ts6 : 413 + D/PE = 3.1 for 1:1 ratio
483 + : 285 an D/PE = 3.3 for 2:1 ratio

In the Ts3 data, Ts3 is deficient while an is normal; whereas, in the Ts6 data, Ts6 is only slightly deficient and an greatly so. If these effects are due to an interaction between an and either Ts3 or Ts6 as Emerson 1941 News Letter (p. 15) suggests, the interaction is presumably different for the two tassel-seed genes.

M. J. Murray