2 BULLETIN 1062, IT. S. DEPARTMENT OF AGRJCITLTURE. 



designated as types A to F, inclusive (PI. I) . Where the starch zones 

 of the crowns and tips of the kernel were completely united and the 

 kernel was entirely opaque to transmitted light, it was designated 

 as type A, or starchy. Kernels of which three-fourths of the en- 

 dosperm was starchy were designated as type B. Kernels in which 

 half of the endosperm was starchy were classed as type C, and those 

 in which about one-fourth of the endosperm was starchy represent 

 type D. Kernels showing only a narrow band of starch at the crown 

 were designated as horny, or type E, and a few strains in which prac- 

 tically all of the endosperm was horny were designated as very 

 horny, or type F. These types are shown in Plate I. 



With this classification it was easy to separate the character of 

 starchiness from that of indentation, with which it has been too fre- 

 quently confused. Starchiness is characteristic of chaffy, immature 

 ears, but is not necessarily associated with normally matured ears 

 of rough indentation. Ear types commonly encountered are illus- 

 trated in Plate II. 



Most of the ears studied fell within the range of types C, D, and E. 

 Some strains averaged " C " in composition, and some northern In- 

 diana strains of Ninety-Day corn averaged " F " in composition, or 

 very horny. The larger, later maturing strains grown in the south- 

 ern part of the State seemed to show some tendency to be more 

 starchy than those grown in the northern part. 



RELATION OF ENDOSPERM CHARACTER AND EAR INFECTION. 



The results of a study of the relation of ear composition to ear 

 infection are shown in Table 1. This study was made upon repre- 

 sentative ears supplied to this office for germination and field experi- 

 ments during 1918 and 1919 by a number of the more prominent 

 seed-corn growers of Indiana. On the basis of character of endo- 

 sperm, the ears in each sample were separated into the two classes, 

 starchy and horny, the dividing line being placed arbitrarily between 

 types D and E. In studying the germination record of these ears, 

 all ears were considered infected the kernels of which were charac- 

 terized by growths of Fusarium spp., Diplodia zeae, or Penidllium 

 spp. when accompanied by disorganized tissue surrounding the scu- 

 tellum in each of duplicate germination tests made upon the lime- 

 stone-base table germinator, as described by Hoffer and Holbert. 1 



1 Hoffer, George N., and Holbert, J. R. Selection of disease-free seed corn. Ind. Agr. 

 Erp. Sta. Bui. 224, 16 p., 20 fig., 1918. 



