1!. V. T. — 709. 



AN IMPROVED METHOD OF ARTIFICIAL POLLINA- 

 TION IN CORN.' 



INTRODUCTION. 



Tn the breeding- of corn, if accurate records regarding parentage 

 are to be kept, all pollinations must be done by hand. In the 

 merhods of study now popular many pollinations are self-pollina- 

 tions ; that is, it is necessary to place the pollen of a plant on the silks 

 of the same plant and protect the silks from all other pollen. By 

 the methods usually employed it is impossible to be cei-tain that all 

 foreign pollen is excluded. This uncertainty prevents the placing 

 of confidence in the ancestry of plants that exhibit unexpected 

 characters. 



From Avhat is known of reversions and mutations the appearance 

 of characters assumed to be absent from the parents, though of rare 

 occurrence, must still be considered. A technique so faulty that the 

 evidence on this point can not be relied upon removes all hope of 

 touching some of the most vital problems in heredity and renders all 

 data regarding the absolute purity of the germ cells valueless. It is 

 believed that the method here described makes it possible to place 

 the same confidence in the self-pollination of corn as in plants which 

 are not wind-pollinated. 



METHODS USUALLY EMPLOYED. 



The usual method of making self-pollinations is to inclose the tas- 

 sels and young ears in strong papei- bags. When pollen has accu- 

 mulated in the bag surrounding the tassel and the silks have emerged 

 from the young ear. the bag containing the pollen is removed. The 

 ear is then uncovered, the pollen dusted over the silks, and the bag 

 replaced on the ear. During the operation the silks are necessarily 

 exposed for a shoil tini(> to any j^ollen that may be floating in the air. 

 A number of refinements have lieen devised by different operators 



^ For the oricinal siifrgpstion of tho motliod hore described, the writers? are indebted to 

 Dr. L. J. r.riKgs. of the Bureau of I'lant Industry. 



[Cir. S9] 3 



