INHERITANCE OF ALEURONE COLOR IN MAIZE 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 265 



Merle C. Coulter 



Interested in the pedagogical value of plant genetics, the 

 writer was impressed with the fact that the bulk of our knowledge 

 comes from experiments with corn. An investigation was under- 

 taken, therefore, with no more definite object than to discover how 

 dependable some of these classic experiments actually are. During 

 three years of rather interrupted and limited investigation, this 

 undertaking, as might be expected, has been rewarded by numerous 

 results that have been interesting and suggestive, but by prac- 

 tically none that as yet can be regarded as conclusive. In view, 

 however, of the number of investigators, professional and amateur, 

 who are now interested in inheritance in corn, it is felt that a brief 

 statement of a few of the results may be useful. 



Technique 



The writer's experiences in matters of manual technique will 

 undoubtedly be of interest to amateurs. The grosser mechanics 

 of corn crossing are simple and familiar. The difficulties are 

 mainly two: (i) to avoid exposing the silks to chance foreign 

 pollen at the time the cross is made, and (2) to insure full pollination, 

 and hence full ears. It is common practice to remove, totally or 

 partially, the bag which covers the silks when the pollen is applied. 

 This involves momentary exposure of the silks to chance for- 

 eign pollen, plenty of which is almost sure to be circulating in 

 the air. Thorough distribution of the applied pollen over the 

 silks is then attempted by shaking the bag in some way. In the 

 hands of an experienced operator this method is not only adequate 

 but rapid. When the writer attempted this, however, the results 

 were not satisfactory. Less than half the ears were fully pollinated, 

 and there were quite a number of cases in which about 5 or 6 grains 

 of foreign pollen had evidently been admitted. For the second 

 season's work, therefore, a simple mechanical device was employed, 



407] 



(Botanical Gazette, vol. 69 



