105 

 Improved Technique for Corn Pollination. 



Paul Weatherwax, Indiana University. 



Many devices have been described for tlie control of pollination in 

 various plants, and a number of these have been found especially ser- 

 viceable in the extensive work that has been done in corn breeding. The 

 best points of two or three of these methods have been combined and 

 used successfully during the past year. 



The protection of the female inflorescence is made of an 8x12 sheet 

 of typewriter paper. Its construction can best be explained by reference 

 to the accompanying diagram. (Fig. 1.) Half an inch along one end 

 of the sheet is folded over and pressed down along AA; one side is sim- 

 ilarly folded along BB, and the other along CC. One of these latter folds 

 is glued down to the other, and the result is a long, flat envelope, open 

 at both ends and reinforced at one end by the half-inch fold. 



The glue employed may be any of the common brands that are pur- 

 chased ready for use; this can be rendered almost insoluble by the addi- 

 tion of a small quantity of any readily soluble chromate and drying the 

 pasted article in sunlight. To make the envelope waterproof, a solution 

 of hard paraflftn in benzole is applied with a tuft of cotton. The evapor- 

 ation of the benzole leaves the paper dry and smooth but impregnated 

 with paraffin. 



The manipulation of the device is simple. It is usually best to re- 

 move the lamina of the leaf in whose axil the ear is borne and to slit 

 its sheath down the sides. The reinforced end of the envelope is then 

 slipped over the ear and made tight by means of a tuft of cotton stuffed 

 in from below. The top of the envelope is folded over and fastened with 

 a paper clip, which is tied loosely to the stem of the plant. (See Fig. 2.) 

 When the silks have appeared, the clip is removed without untying from 

 the stalk, the pollen poured in, and the clip replaced. 



As the ear continues to grow, the string by which the clip is tied 

 slips upward on the stalk, and little further attention is required. The 

 tuft of cotton is compressed to make room for the increasing thickness 

 of the ear, until the latter is large enough to burst the envelope without 

 injury to itself. By this time the silks are usually no longer receptive. 



