BEGINNINGS OF THE HETEROSIS CONCEPT 



21 



of fluctuations of so definite and easily observed a quantitative character as 

 the number of the rows of grains on the ears. The crop was carefully har- 

 vested and placed in a crib. On November 7, 1904, I counted the rows of 

 grains on every ear, with the result shown in figure 2.1. The 524 ears ranged 

 over the seven classes from 10-rowed to 22-rowed. The most populous classes 



8 



10 



12 14 



NUMBER 



16 18 20 



OF GRAIN ROWS 



Fig. 2.1 — Frequency curve of grain-rows of 524 ears of white dent corn. The total progeny 



of presumably a single ear of corn received from the Crotty farm near Topeka, Kansas, and 



grown at the Station for Experimental Evokition in 1904. 



were the 14-rowed with a frequency of 201, and 16-rowed with 153 individual 

 ears. The mean was 14.85 ± .06. 



No photograph nor verbal description was made of the parent ear, since 

 there was no intention at the time of its planting to use it in a breeding ex- 

 periment. But its characteristics must have been accurately duplicated in all 

 of the crossbred families subsequently grown, as well as in most of the Fi hy- 



