PAPERS ON AGRICULTURE 89 



frequency distributions are represented graphically in Fig. 2, 

 the height of ear in inches being plotted as abscissae and fre- 

 quency as ordinates. The dotted lines represent the means. 

 It is easily seen that the parent strains scarcely overlap at 

 all, and that the cross is intermediate between them. The 

 coefficient of variability in respect to height of ear of the cross 

 is also intermediate between the coefficients of variability of 

 the parents. 

 INTERNODES 



Low Ear 

 Low Ear High Ear x 

 High Ear 



Average Number 4.91 10.23 7.36 



Number 4.91 10.23 7.36 



The number of internodes in the cross was intermediate 

 between those of the parents, the mean number of the cross 

 being 7.36 as compared with 4.91 in the low ears and 10.23 

 in the high ears. The height of ear is due not only to the 

 number of internodes, but also to the length of internode, and 

 in this respect the hybrid is likewise an intermediate, the aver- 

 age length of internodes in the hybrid being 5.32 inches, 

 whereas in the low ears it is 3.59 inches and in the high ears 

 6.65 inches. Fig. 3 shows graphically the relative heights 

 of ear in the three strains and also the average length of in- 

 ternode for each strain drawn to the same scale. 



An interesting difference resulting from the breeding for 

 high and low ears is in the time of maturity. Although no 

 attention has been paid to this character in making the selec- 

 tions, the low ears normally mature 10 to 15 days earlier 

 than the high ears. In 1914 the low ears required only 54 

 days from planting to produce tassels ; the high ears required 

 65 days, and the cross 56 days, showing it again to be inter- 

 mediate although favoring the Low Ear parent. 



YIELD 



Low Ear 

 Low Ear High Ear x 



High Ear 



Bushels per acre 48.4 44.4 66.4 



