MAIZE WITH SILKS MATURING BEFORE THE TASSELS. 5 



we have unwittingly progressed thus far may it not be possible to 

 proceed to the still more desirable condition of proterogyny % 



Self-pollination, while less desirable, is at the same time less 

 precarious than cross-pollination. It seems to be an inefficient 

 arrangement to have the opportunity for the deleterious (but rela- 

 tively more certain) self-pollination precede the opportunity for 

 the advantageous (but more precarious) cross-pollination. If the 

 conditions could be reversed by having the plants moderately pro- 

 terogynous, the proportion of cross-pollinated seed would be greatly 

 increased, while if by any chance the silks failed to receive foreign 

 pollen, pollen from the same plant would be forthcoming as a last 

 resort, and the danger of poorly filled ears would be avoided. 



The advantages of proterogyny in maize appear so important 

 that the effort has been made to develop this habit in some of the 

 improved varieties. Occasional proterogynous plants are to be 

 found in most varieties, and wherever such plants have been observed 

 in our experiments seed has been saved and planted the following year. 



In many instances it was found, however, that the proterogyny 

 was only apparent, resulting from an abnormal development of the 

 staminate flowers, and many of the plants noted as proterogynous 

 proved to be sterile as far as the production of pollen was concerned. 

 As with other characters that result from injury or abnormal condi- 

 tions, proterogynous variations of this nature have been found 

 to be inherited very imperfectly, if at all, and little progress has 

 been made by this method. The discovery of a variety that appears 

 to be regularly proterogynous makes the outlook for improvement 

 in this direction much more hopeful. 



Two ears of a red pop corn, purchased at Granada, Spain, by Mr. 

 Waiter T. Swingle, of this Bureau, in January, 1912, and planted at 

 Lanham, Md., the following spring, produced plants, nearly every one 

 of which was proterogynous. 



The ears of this variety are so small that the variety will probably 

 be of no economic importance except perhaps as a pop corn. The 

 subsequent behavior of the variety can not be safely inferred from 

 its behavior the first year, but that the proterogynous tendency exists 

 to a marked degree seems certain, and to attempt its transfer to our 

 improved varieties would seem well worth the effort. The present 

 account is published in the belief that those interested in developing 

 new types of maize will find valuable breeding material in this strain. 

 Only a small quantity is on hand, but a few seeds can be supplied to 

 those wishing to make a study of this variation and to assist in deter- 

 mining its economic importance. 



The improvement of maize varieties should be looked upon as a local 

 problem. The acclimatization of an improved variety is likely to 

 entail nearly as much time and labor as the original work of improve- 



[Clr. 107] 



