4 ARTIFICIAL POLLINATION IX COEN. 



to reduce the chances of the silks receivinir foreign pollen. The 

 most effective is that proposed by Roberts.^ In his experimental 

 field the tassels are all bairged before they begin shedding pollen; 

 there is thns no pollen free in the air of the field, except the 

 small quantity that escapes Avhile making the hand pollinations. 

 The quantity of free pollen is furtlier reduced by an ingenious 

 method of applying the pollen by means of an insect-powder "gim" 

 or spring blower. By this method the pollen is distributed so per- 

 fectly that but a small part of the amount nsually required is suffi- 

 cient. Another precaution nsed by careful operators is to wash 

 their hands in alcohol after each pollination in order to destroy the 

 vitality of any pollen that might remain on the hands. 



EXTENT OF CONTAMINATION. 



Regarding the amount of foreign pollen that gains access to ears 

 pollinated in the ordinary way, East states that in 53 ears bagged 

 and the bags not removed 14 seeds developed and in 25 ears manipu- 

 lated as in pollinating but to which no pollen was applied 20 seeds 

 v>'ere formed." These figures are not very different from results ob- 

 tained bj^ the writers in using the same method. When lOG ears were 

 bagged and the bags allowed to remain, 10 seeds were produced on 

 5 ears. The operation of pollination applied to 23 ears, but without 

 the application of pollen, produced in all 1 seed. Our somewhat 

 more fa\orable results are probably the residt of bagging the ears 

 at an earlier date. 



DESCRIPTION OF THE NEW METHOD. 



The method here proposed involves the use of strong paper tubes 

 about -i inches in diameter and 40 inches long. Longer tubes are 

 sometimes necessary for very tall plants, and for short plants a piece 

 may need to be torn off. To apply the tubes, one end is pushed over 

 the tassel and wired firmly at a point just below the upper end of the 

 last leaf sheath. The other end of the tube is then brought down 

 and passed over the young ear and securely wired. (Fig. 1.) In 

 pulling the tube down to the ear the tassel will be bent to one side in 

 such a way that as soon as the anthers open the pollen falls down the 

 tube and comes in contact with the silks. To protect against any 

 foreign pollen which may be present on the tassel or ear when bagged, 

 the tubes should be put in place four or five days before the silks are 

 expected to appear. The greatest difficulty in applying the tubes is 



1 Roberts, H. F. A New Method of Corn rolliuation. American Breeders" Magazine, 

 vol. 2, no. 1, 1911, p. .j5. 



2 East, E. M., and Ilnyes. II. K. Inheritance in :Maize. r.ullitin liJT, ("onnecticut Agri- 

 cnltur.il Experiment Station, 1011, pi). .".O-Ml. 



[Clr. 89] 



