XI. 



MAIZE. 



IMPROVEMENT OF VARIETIES. 



251. Pollination. — Maize is said to be wind-fertilized, since 

 the extremely abundant pollen is carried long distances by the 

 wind and often deposited upon silks of ears quite remote from 

 the tassel bearing the pollen. Notwithstanding the large amount 

 of observation and experiment, the extent to which maize is 

 cross-fertiiized and to what extent it is self-fertilized in actual 

 practice has not been clearly established. It is believed by 

 many, however, that since the pollen appears to develop slightly 

 in advance of the silks of the same plant, and since the tendency 

 of the currents of air would be to carry the pollen away from 

 the plant producing it, that cross-fertilization is the rule and 

 self-fertilization the exception. It has been clearly established, 

 however, that both cross-fertilization and self-fertilization can 

 readily be effected. Artificial or hand pollination usually does 

 not produce as good results as when pollination takes place in 

 the natural way. 



The ovules are fertilized in order of sequence from butt to 

 tip. Since the tip grains develop last, the tip of the ear is the 

 most variable, due to variations in soil, cultural or seasonal 

 conditions. It is probable that the filling out at the tip of the 

 ear should be looked upon as the result of environment more 

 than as an hereditary or variety characteristic. (243) 



252. Influence of Current Cross. — The influence of pollen 

 upon the grain or fmit which immediately develops, called xenia, 

 has received considerable study especially in maize. That the 

 character of the male pollen may affect the endosperm of the 



