No. 542] 



NOTES AND LITERATURE 



L13 



Purple and Non-Purple Aleurone Cells 



The experimental data relating to crosses between purple and 

 non-purple races indicate two factors, V and (/, which, when to- 

 gether, produce purple color in the aleurone layer. In some of 

 the non-purples used one of these factors was missing, in others 

 both. In certain combinations one of these factors alone pro- 

 duced faintly colored purple. In most of the crosses splashed 

 purple occurred, part, but not all, of the heterozygotes having 

 this peculiarity. It was not hereditary, but behaved in subse- 

 quent generations as pure purple. 



In one family red aleurone occurred in F 2 . It appeared to be 

 due to the interaction of two factors B and C. 



In one family of this cross (purple X non-purple) the F 2 gen- 

 eration gave purples, reds, and non-purples in the ratio 12 : 1 : 3. 

 The actual numbers were 1,843 : 188 : 545. The ratio 12:1:3 did 

 not occur in F 3 , but instead one fifth of the ears bearing F„ 

 grains gave the ratio 9:3:4. Several possible hypotheses to 

 explain these anomalous results are discussed and discarded, 

 amongst them Bateson and Punnet's hypothesis of the formation 

 of gametes in the ratio 1AB : laB : lAb : lab. The data from F, 

 agree best with the assumption that the constitution of the two 

 parent types was pcB and PCR respectively, but the F 2 ratio 

 is not explained by this hypothesis. The authors leave the ques- 

 tion as to the real explanation an open one. The reds in this 

 family were different in color from the reds of the family pre- 

 viously mentioned. Not only that, but all the F, reds found in 

 this family proved to be homozygous, indicating that both par- 

 ents possessed the factor B. 



Other families of this cross gave results that indicated the 

 presence in the non-purple parent of a factor which more or 

 less completely inhibited the development of purple. Some non- 

 conformable results were found, due probably to the presence of 

 other factors, one at least of which appeared to modify purple 

 by making it lighter. 



In the above crosses xenia was found as follows: when non- 

 starchy races were fertilized by pollen from starchy races (no 

 xenia appeared in the reciprocal cross) ; when non-yellow endo- 

 sperm is crossed with yellow endosperm. In this case xenia al- 

 ways appeared when yellow was used as the male parent. It 

 also appeared in the reciprocal cross when the grains of the fe- 

 male parent had extensive development of soft starchy endo- 

 sperm at the end of the grain, as in these cases the heterozygous 



