A NEW SERIES OF HYBEIDS BETWEEN DIVERSE TYPES. 21 



borne on tubercles, the leaves are few and very long and slender, 

 the tassel is frequently unbranched, the spikelets are in groups of 

 four or more instead of two, and the clusters are opposite each other 

 instead of alternate. Even the root system is distinct from that of 

 any of the common varieties of the United States, being spread out 

 near the surface of the ground where the only available water is to 

 be secured in the regions where this type is native. Many varieties 

 inside this type differ among themselves much as the classes of flint, 

 dent, and pop corns differ from each other. In fact, a closely similar 

 series exists in this tropical type, there being varieties which judged 

 by the ears, would be classed as flint and others as pop and dent corns. 



Wliile this type is one of the most distinct, many other tropical 

 forms possess characters and habits that are entirely absent or only 

 faintly indicated in United States varieties. Peculiarities of other 

 tropical types will be, mentioned in connection with the different 

 crosses that are about to be described. 



With a view to securing types adapted to sections of the country 

 where United States varieties are unsuccessful, a considerable series 

 of tropical types and varieties has been brought together. In the 

 season of 1908 about 75 crosses were made among these tropical 

 varieties, and also between them and several United States varieties. 

 A number of these hybrids were grown in the summer of 1909 at 

 Lanham, Md., a few miles from Washington, D. C. The parent 

 varieties of 16 of these crosses were included in the plat and their 

 behavior noted in comparison with the crosses. The experiment 

 was considered as merely preliminary and but 16 hills of each 

 variety were grown. Wliile this number is altogether too small to be 

 conclusive as a comparison of the values of the different crosses, 

 the results as a whole are very significant as an illustration of the 

 general value of first-generation hybrids. It becomes evident that 

 the increase in vigor that earlier experiments have proved to be the 

 rule with crosses of more or less closely related strains has also a very 

 wide application among even the most primitive, unselected, and 

 diverse types of corn. In 14 of the 16 crosses the yield exceeded 

 the average of the parents. In 12 cases it exceeded the yield of either 

 parent, the average increase for the whole series being about 53 per 

 cent. 



In the following brief account of the hybrids and their parents, 

 the descriptions will for the most part be confined to the usually 

 recorded characters of height, yield, and character of the ear, which 

 data are sufficient to make the results of this experiment comparable 

 with those previously reported. Detailed observations of the behavior 

 of the parental characters in these and other hybrid combinations 

 have been made, but are not needed for the purpose of this report. 



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