BEGINNINGS OF THE HETEROSIS CONCEPT 29 



I cannot now determine, the corresponding sib crosses in Strain B were not 

 included in my 1909 report. The results were essentially the same as were re- 

 ported for the sib cross in Strain A. Selfed Strain B (see Table 2.4, family 

 C6.ll) showed average heights of plants 2.3 meters, and yielded 66 ears 

 weighing 13.0 pounds. The two sib crosses produced plants 2.5 meters tall 

 and yielded 89 ears weighing 28.5 pounds. Distribution of the grain-row 

 frequencies was closely similar in selfed and in sib-crossed Strain B, but sig- 

 nificantly higher in the latter: 



_, . Totals Averages 



Grain-rows 10 12 14 16 18 



Selfed 2 20 26 17 1 66 1.3 8 



Sib-crossed 3 15 45 18 8 89 14.2 



There was abundant evidence that the sib crosses showed a greatly re- 

 stricted advantage over self-fertilization. It was also clearly indicated that 



TABLE 2.4 



GRAIN-ROW COUNTS, HEIGHTS, AND YIELDS OF 

 WHITE DENT MAIZE GROWN IN 1908 



* The remaining nine rows were not measured and described, "for lack of time.' 

 lanlil^'' '''''"' ""'^"^ ^°"' ^^'' "^'^^ '■*' ''^'^^' ^""^ ^° '"""^ °^ ^''''"'' °^ ""'^'""^ °"'^' "'"^ twenty-rowed ear was used for 



